Category Archives: Computing Aboard

Navigation Via PC or Tablet Computer

A long-time cruising friend recently asked: “I’ve been researching a replacement for my circa 2000 RayMarine navigation system.  Clearly, there are any number of commercial systems that integrate chart/radar/depth, etc.  However, I’ve been looking at PC or laptop alternatives.  I’m curious as to what folks may be using out there, i.e., iNavx, etc.”

There are three mix-‘n’match categories of “navigation equipment” that combine into solutions that address this question:

  1. a full suite of made-for-purpose navigation equipment sourced from a major manufacturer of marine products (ComNav, Furuno , Garmin, Lowrance, Raymarine, Simrad, Sitex, etc.), or
  2. a network-connected combination of selected made-for-purpose marine navigation equipment and general purpose PC/tablet computing equipment running navigation software, or
  3. stand-alone PC/tablet computing equipment running navigation software (apps).

In 2017, all three alternatives are possible.  Options are listed above from most expensive to least expensive.  Items 1 and 2 are equally functional for navigation and piloting today.   Item 3 has feature-set limitations because some features are not available in the PC market, (RADAR scanners, AIS transponders, Autopilots, etc) and these features are unlikely to appear in that market in the reasonable future.  There is no “one-size-fits-all” right answer.  This article examines some of the pros and cons.

The value proposition:

Reality: All made-for-purpose marine equipment solutions and PC/tablet solutions have some limitations.

Traditional made-for-purpose marine equipment: is expensive to buy, often requires expensive professional installation, obsoletes quickly (resulting in a short feature-set lifespan), is constrained in its versatility, often requires expensive and/or proprietary charts, is relatively difficult/complex to upgrade and backup, and doesn’t always play well on boats fit with equipment from multiple manufacturers.  On the other hand, made-for-purpose equipment is rugged, weather-resistant,  viewable in bright sunshine, and (because of it’s limited feature-set) has a somewhat simpler learning curve for the end user.  These factors combine to produce a limited value calculation.

General purpose computing devices, including the navigation software applications necessary to run on them: are relatively inexpensive, utilize free NOAA (ENC) and USACE (IENC) navigation charts, are easily replaceable, are light and portable, are easily upgradable (so have a longer feature-set lifespan), and are extremely versatile through the many software applications that are available today.  The user interface for PCs and tablet client devices are based on the operating system they use (Microsoft Windows, Apple Mac OSX, Apple iOS, Google Android), but most operating systems are generally familiar to most people from other life learning and experience.  On the other hand, these devices are generally not made for outdoor use, may be difficult to view in bright daylight, and can be sensitive to over-heating in direct sunlight.  Overall, even with the negatives, this equipment can offer a very attractive value calculation.

There are significant learning curves associated with all marine equipment and general purpose computing products.   The learning curve can be challenging and intimidating for many users.  Some manufacturer’s user interfaces are more intuitive than others.  Personal preference and past experience with technology equipment has a significant effect on both choice and success.

Aboard Sanctuary:

For navigation and piloting aboard Sanctuary, I personally depend on a hybrid solution consisting of a combination of made-for-purpose marine equipment and PC/tablet computing equipment with appropriate software apps (alternative #2, above).  Today, the flow of data in marine data networks is mostly one way, with data traveling from the marine equipment to the PC equipment, via a multiplexor.  (See my article on Marine Data Networks on this site, here:   Aboard Sanctuary, this arrangement allows us to utilize made-for-purpose equipment in a way that lengthens the service life (obsolescence) of it’s aging feature set.  We use it to do the core work of the helm; i.e., run routes via the autopilot and watch for obstructions and marine hazards using RADAR and an AIS receiver.

We pre-plan our routes on our PC before day-of-travel.  When on-the-water, I rely primarily on our Apple iPad for piloting, risk management and risk avoidance operations.  We use our Macbook Pro laptop running Rosepoint’s Coastal Explorer 2011 for route pre-planning.  We rely on our iPad tablet running SEAiq, Navionics, Ayetides, Anchor Watch and various weather apps for general navigation and piloting decisions.  Due to their vintage, our made-for-purpose chart plotters do not support Active Captain.  I rely on iPad apps for ActiveCaptain anchorage and location reviews and marina contact information.  (And yes, my email and Peg’s Facebook are also available via the iPad, even while the nav app “stands watch.”)


Aboard Sanctuary, we have a now-obsolete Raymarine DX500s Fishfinder which serves as our primary depth sounder.  At the time of writing this article, the screen appears to be dying, but the internal electronics and NMEA0183 data network are operational for actual depth measurement.  Because of the capabilities of the iPad app (SEAiq), I don’t need visibility to the depth sounder’s screen.  I’m stuck with the DS500x for now because the Airmar sonar transducer is not compatible with newer versions of depth sounder, so I basically can’t upgrade the device without upgrading the transducer (a “project” to be faced in the months ahead).

I have a now-obsolete two-plotter Raymarine RL70CRC/RN300 GPS/chart plotter system that serves our salon and flybridge.  For cartography, this equipment uses expensive C-MAP chip cartography which I already own, but is prohibitively expensive to update or extend.  The C-MAP cartography works fine, but we very rarely use it anymore, since the SEAiq app on out iPad duplicates it’s capabilities at no cost.  Our Raymarine system has an integrated RADAR scanner.  The RADAR is not up to the capabilities of newer digital HD RADAR, but it is “adequate to the task.”  We occasionally use RADAR for MARPA, but mostly for tracking nearby heavy weather.  All of this is an old technology that continues to work acceptably well for us.

We have full chart redundancy via our made-for-purpose Garmin GPSmap 547xs chart plotter.  The 547xs has a diminutive screen size with tiny text, which limits it’s usefulness.  We use the 547xs almost exclusively for “driving” routes via our Garmin GHP10 autopilot.   The GPSmap 547xs does have modern CHIRP sonar sounder capability, as yet not installed.  The GPSmap 547xs also monitors our ICOM MXA5000 AIS receiver, which the Raymarine chart plotter cannot.  (I recommend AIS transponders be used ONLY for poor visibility, night operations, offshore operations and all operations on the US Inland Rivers.  Otherwise, AIS transponders are not necessary on pleasure craft on the US East Coast, and generally serve to create a false sense of security among users who generally do not understand the limitations of the underlying technology.)

In August, 2013, I installed a DMK 11A “multiplexor.”  The inputs to the multiplexor are our collection of NMEA0183 and NMEA2000 data networks serving our onboard marine equipment (five NMEA0183 networks, one NMEA2000 network and one Raymarine SeaTalk network).  The multiplexor re-formats the data into standard Ethernet data packets, and pumps the data out over wi-fi.  The multiplexor’s wi-fi interface is linked to our onboard Cradlepoint router, to which the multiplexor is just another ordinary client device.  Software apps that can interpret the data and run on any PC or tablet computer allow that computer to become a fully-portable wireless nav station.

I use the multiplexor’s wi-fi feed with Rosepoint’s Coastal Explorer 2011 on the MS-Windows side of my Macbook Pro.  That provides complete navigation redundancy in our salon.  I also use SEAiq Pilot and OpenCPN on the OSX side of my Macbook Pro.  One of the greatest advantages of SEAiq is that the user interface is identical across operating system platforms (iOS, Android, OSX and Windows versions), so regardless of the mix of operating systems, there is only one learning curve for the user of the software.  I use “SEAiq International” on our iPad (iOS).  The iPad version of SEAiq Pilot is professional-quality app that is used by working professional Chesapeake Bay pilots and Harbor pilots worldwide on large ships.   When my brother is aboard, he runs SEAiq on his VerizonWireless Android tablet.   With our multiplexor and suitable software apps that can interpret and display the data, our PC/tablet/smartphone equipment becomes a fully capable, wireless, fully portable chart plotter console.

With the above equipment platform, we have used our iPad since 2013 as our primary navigation device – the device from which our navigation and safety decisions are made.  Our Garmin and Raymarine chart plotters provide redundancy.  An Android tablet with suitable software apps can do what our iPad does, but just as Windows PCs are made by many manufacturers, Android hardware is “versionized” by several different manufacturers.  Depending upon the particular hardware customization, Android software can be finicky to configure and support.   The iPad-based stuff “just works.”

Transit Planning and Cruising:

I have used Coastal Explorer since 2006.  By way of that prior experience, I continue now to create detailed transit routes on my laptop using Coastal Explorer.   I load my routes into our Garmin GPSmap 547xs chart plotter.   Today, we need the Garmin chart plotter to “drive” the autopilot via our NMEA200 data network.  Our multiplexor passes along compass data (HDG), GPS and route data (lat/lon, SOG, COG, DTW, BTW, XTE, etc), sounder data (DPT, DBT, MTW), and all flavors of AIS data (!A).  All of that data is displayed by SEAiq on my iPad.   SEAiq uses the free NOAA and USACE charts, both raster and vector.   I update the charts at my convenience, usually when at a marina that provides reliable and fast wi-fi access to the Internet.   We maintain all of the US ENC charts for the US East Coast from Maine to Texas, the Great Lakes and the IENC charts of the Inland Rivers from Lake Michigan to Mobile and NOLA.   We don’t bother with Puerto Rico, the US West Coast, Hawaii or Alaska because I have no need for them, but they are all available, free.   SEAiq International is about $40, and SEAiq Pilot is about $200.  There are several multiplexor device alternatives; the  DMK11A was $400 from

Below are links to several articles on my website that describe all this in more detail.

  1. describes my Cradlepoint SOHO router configuration and Internet connectivity alternatives that I use on the boat.
  2. is a somewhat dated product description of SEAiq, but it will make the point.
  3.  is a description of NMEA0183, N2K and Ethernet networks, and the role of hardware and software apps that are needed to make up a functional system.

Return on Investment Considerations:

Yes, I use, and rely upon, our iPad for on-water piloting and navigation.

A new Garmin 7212 (now obsolete and no longer in production) would be $3000 or more, without charts.   Current-generation made-for-purpose systems would far exceed that.  Then, absent DIY installation skills, add the cost of professional installation.  A new iPad, app software and a multiplexor together would cost around $1400.   To me, the iPad is a simple, elegant, solution at a price-point that is at least 1/3 the cost of made-for-purpose marine hardware.  The iPad solution is reliable, and easily replaced almost everywhere if something bad were to happen.   Tablets need power to keep batteries charged, but are otherwise fully portable.   Tablets can be hard to see and can be subject to over-heating in direct sunlight, so care in handling is required.   Even considering these limitations, I find my iPad to be a great value proposition!

Specific to the Apple iPad, in the US, FCC regulation requires cell phones to have E911 capability, which means the ability to provide lat/lon location when a caller dials “911” from a cellular telephone.  In the iPad, to meet that requirement, a GPS receiver is built on the cellular telephone chip.   The GPS “comes with” the cellular telephone capability.   Therefore, iPads used for navigation should have cellular telephone capability.   It is not necessary to activate a cellular account in order to use the GPS.   The iPad’s GPS is fast and accurate.  It provides redundancy for position data should the multiplexor ever fail (it never has)…

As described above, I decided on SEAiq for our navigation needs, but other iPad apps are available.  Garmin BlueChart Mobile is a very basic, free navigation app that requires proprietary for-fee charts and bi-annual updates.   BCM includes Active Captain data, which I consider a “must have” in today’s world.  Navionics is similarly basic, also free, also requires proprietary fee charts, but does not provide Active Captain data.  Lack of ActiveCaptain data is offset by two features that people find useful and that I feel give Navionics a slight edge over BCM.   Navionics contains sounding data on the Inland Rivers, useful if cruising the Inland Rivers.   It also has a feature called “Sonar” Charts.   Dozens of cruising boats submit their own actual tracks, and Navionics develops current realtime sounding data in areas of shallow water.   That can be very useful in shallow areas, like SW Florida, the US East Coast ICW, or narrow passes into shallow anchorages on the A-ICW, Chesapeake Bay and elsewhere.   For both BCM and Navionics, chart subscriptions are annual recurring charges, and some features of Navionics, like that sonar feature, turn into a pumpkin at the end of an un-renewed annual subscription period.   The beauty of running these apps on an iPad is that if a user prefers Navionics, but also wants ActiveCaptain data, it’s easy to add an app that shows ActiveCaptain data.  That versatility is simply not possible (today) with made-for-purpose marine devices.  Note: in November, 2017, Farmin bought Navionics.  Garmin also withdrew BCM from the Apple Store.  These events put into question the future of both BCM and Navionics.

Note: In 4Q2017, Garmin discontinued their BlueChart Mobile app, and it is no longer available from the Apple app store.  Garmin replaced BCM with a successor “ActiveCaptain” app.  The ActiveCaptain app consists of the predecessor BCM features and facilities, but adds the capability to communicate with “compatible” Garmin Chart Plotters and share up-to-date cartography back and forth.  The app remains very basic.  It works and, in BCM-mode, will look familiar to previous users of the BCM app.  The advanced features that are new to the ActiveCaptain app are very welcome.  Garmin continues to make these capabilities available only on a proprietary basis with their own branded equipment, but for those with Garmin equipment, the app seems worth having.  Garmin has also purchased Navionics.  The future of that app is unknown at this writing (December, 2017).

If choosing made-for-purpose marine equipment, I recommend that buyers add new equipment made by the same manufacturer as any equipment that is already in place.  This recommendation is largely based on technical design choices manufacturers make having to do with the use of proprietary data.  I consider the “core components” of a navigation system to be the autopilot and the GPS/chart plotter, since more than other devices, these two devices MUST work well together; especially so for Position (lat/lon), course-over-ground (COG), course-made-good (CMG), bearing-to-waypoint (BTW), distance-to-waypoint (DTW) and cross-track-error (XTE).   Other system components should be of the same manufacturer where reasonable, affordable and possible, including depth sounders.  For weather instrumentation, AIS receiver/transponders, VHF radio DSC interface, and some other devices, which are all quite standardized, mixing manufacturer’s may be OK.

Not specific to Raymarine or Garmin, but generally across the marine electronics industry, manufacturers are moving at a very fast pace (Moore’s Law) to implement ever-increasing processor chip speeds, ever larger internal memory capacities, and ever expanding internal software (firmware) capabilities.   The rate at which new function becomes available and old equipment becomes obsolete is very rapid.  That leads to large capital expense outlays for buyers who try to “stay current.”   My personal observation is, the marine equipment manufacturer’s intentionally do not design for “downward compatibility.”  During my career in a fortune’s 10 computer company, one of the critical design issues for new products was “downward compatibility” (“backwards compatibility”) with existing customer equipment.  That was a critical customer requirement necessary 1) to protect the customer’s pre-existing investment base and 2) to allow for a reasonable and minimally-disruptive upgrade path. The same issues are painfully obvious to all of us as boat owners.  As described earlier, I face that issue today with my depth sounder transducer.

The ability of a manufacturer to offer an expanding feature-set is a function of processor chip speed and internal memory capacity.  Chart plotters and depth sounders are really just specialty computers, after all.  But, improvements in the features of marine equipment that are available to users arise from the software (firmware) capability built-in to the equipment, and software requires memory and chip speed.  Upgrading the physical hardware of made-for-purpose marine equipment is not an activity that is supported by the manufacturers, and certainly not a DIY activity.   Upgrades to firmware are limited to what the manufacturer makes available, and are generally not automatic or simple to accomplish.   By contrast, upgrading PC and tablet hardware is usually quite easy and relatively inexpensive.  Upgrading/adding software apps on PCs, tablets and smart phones is both routine and automatic.  This means that new software capability rolls out in tablet apps and PC software at the same rate and pace and at much lesser retail cost than with made-for-purpose hardware.

Finally, none of the marine manufacturer’s do a good job of standing behind their obsolete equipment.  I found a firmware design error in my Raymarine DS500x Fishfinder in the construction of the $SDDPT NMEA0183 sentence.   I reported that to Raymarine via their user’s web support forum.   After some back-and-forth based on the assumption that I had to be wrong (what could an end-user possibly know?) I was finally able to get grudging agreement from Raymarine that I had proved there was an bug in their device firmware.   The conclusion: “Have a nice life, Jim!   The box is out-of-production.”  No matter that the problem was a Raymarine product defect.  There was no way to upgrade the software in the field anyway, so therefore, apparently no need to fix it.  So, I live with it to this day, and every day I reconcile to never again trust Raymarine as my preferred equipment vendor.  That said, who knows if another vendor would actually be any better?

When the end-user posts a problem or a query to the Raymarine support forum, that often draws a lot of potential hints from other Raymarine equipment users.  Sometimes, that is helpful.   But the actual “experts” from Raymarine rarely “jump in” until there as been some largely wasted back-and-forth.  Does the forum work?   For user issues, yes; usually.   For real engineering issues, it depends on how hard you, as a user, push the gorilla to get a satisfactory answer.   If you get tired of the back-and-forth before the gorilla gets tired, you’ll go away empty-handed and frustrated.

Then there is support for the current line of equipment.   Generally, I find Tech Support is not set up to deal with a knowledgeable user.   I am a reasonably knowledgeable (if I say so myself) DIY user.  When I call Garmin, or write to Raymarine, for tech support, I have a problem that I have already researched, both on the Internet and in the manufacturer’s proprietary website support section.  When I call, I can clearly define and clearly explain the issue (or at least I can explain what it is not).  When I call, I have already updated the firmware, and I have done the basic power and wiring checks.   When I call, I am at the point where I know what I need and I know the information is not available elsewhere.   (By the way, the support section of the Garmin website is poor.   I find it largely unusable, with poor search capabilities, many, many hits that are not applicable to the search, and many distractions.)

The initial contact with Garmin tech support is to take callers through the “re-boot,” “re-calibrate” and “update the firmware,” steps before they take you seriously.   That can result in a lot of wasted time and frustration in back-and-forth exchanges, especially of you call from a location that is NOT the boat.   I personally suspect a lot of people just give up.   (But then, I know that many owners can’t operate the advanced functions of their equipment, including such safety items as DSC on VHF radios.)

I experienced an incident with my Garmin then GPSmap 540 chart plotter related to uploading routes.  With two or three routes to upload, the result was a “Route Truncated” error.   That incident lasted across multiple complimentary hardware upgrades and across more than two calendar years.   Very few people are stubborn enough to pursue that.  Indeed, maybe I’m nuts (none other than Jeff Siegel told me I was), but the failure was in a feature I really wanted to work, and the capability was within the published specifications for the device I bought.  But, every time I called Garmin tech support, I got a different technician.   It became impossible to take a technician new to the problem through the long and detailed pre-existing history of that very complex call.   It was a huge usability problem with Garmin tech support.  It took two escalation-to-management calls to get a senior technician assigned to my case and with whom I could just email status, questions, requests for additional data and case progress back-and-forth.   It was not until I got that done that I even began to make progress.

It’s undeniable that general purpose computing devices have their own “usability issues,” of which screen brightness and battery life are two.   But, most functional improvements come from improvements in software capability.   The commercial software applications available today for tablets and PCs are amazingly feature-rich.  In inclement weather, I keep my iPad safe by putting it in a one-gallon Ziploc bag.   Works just fine that way.   I have several different navigation apps loaded there which provide alternatives if needed.


As to the value proposition for all this, I would assume for all of us, boating is a discretionary expense.  Even though I may want the new gee-wiz function a manufacturer has developed, like HD RADAR, I do not want to have to spend thousands of dollars every 2-1/2 to 3 years to upgrade my navigation electronics suite just to be able to take advantage of the emerging features.   When we bought Sanctuary in 2004, there wasn’t a PC/tablet alternative to marine equipment.  I installed the then-current Raymarine chart plotter and RADAR system.   In the ensuing 12 years, that 2004 equipment investment has become several “generations” of Raymarine equipment releases obsolete.  To stay current with Raymarine’s pace of feature development, I would have had to upgrade my equipment three times at a minimum DIY cost approaching $5K each time.   In a word, “horsepucky” to that.   I am reluctant to invest in my system at all any more, because I feel like made-for-purpose equipment is an almost valueless upgrade to the base value of the boat.   Any future buyer of any boat with any navigation system older than a couple of years is buying an obsolete system, and will probably want to upgrade anyway.  There’s no value in making that upgrade for the current owner.

So, there isn’t a clear yes/no to the basic question of PC navigation; just a collection of pros and cons. Both types of solutions have merits, both are completely feasible, and both have limitations.   A very great deal will depend on personal preferences and personal self-confidence.   With the advent of made-for-purpose offerings like the new Furuno 1st Watch wireless RADAR unit (only power required; no signal cable up the mast, app on a tablet to display the RADAR image), PC and tablet solutions become more and more viable for more and more true navigation uses.   Watch this space as it evolves into the [near] future!

Choosing a PC/Tablet App for Cruising: following, I have created a template example of some (but NOT all) navigation application software products and some (but NOT all) factors that cruisers might like to have available.  The matrix, when complete, helps in selecting apps that will work for the personal preferences and navigational needs of different boats and different captains.  There is a great deal of Internet folklore associated with all of these apps.  Some are excellent for beginning cruisers, and some are capable of supporting advanced user requirements.   By way of illustration, I have populated some (but NOT all) specific detail for products I personally own and have personally used.  It’s clear that the matrix can provide a helpful visual means to screen products for personal suitability.  app_matrix

Hardware Considerations: in evaluating one’s interest in PC/tablet navigation solutions, consider the available hardware solutions as well as the navigation apps:

PC/Tablet hardware choice:

  1. cost
  2. network support requirements (NMEA0183, NMEA2000, multiplexor, Ethernet, Bluetooth)
  3. mechanical mounting requirements
  4. contains internal GPS vs requires external GPS
  5. screen visibility in bright sunlight
  6. overheating in direct sunlight
  7. weather resistance
  8. battery life
  9. has data back-up tools
  10. ease of replacement
  11. manufacturer provides good technical support (operating system & applications)

Made-for-Purpose marine hardware products:

  1. cost (product plus installation)
  2. network support (NMEA0183, NMEA2000, Ethernet)
  3. Ethernet interfaces provide for end-user data transfer, not just proprietary manufacturer use
  4. mixed-manufacturer compatibility
  5. time to expected obsolescence (expected feature-set lifespan)
  6. portability limitations
  7. versatility (weather, ActiveCaptain, tides ‘n currents, anchor watch, cruising guides, social media, email)
  8. speed (chip, memory)
  9. ease of data entry (route & waypoint creation/modification) (touch screen vs keypad)
  10. boat motion interferes with touch screen operation when sea states are moderate to lumpy
  11. complexity & frequency of software update(s)
  12. complexity, frequency & cost of chart updates(s)
  13. warranty period
  14. support period
  15. ease of warranty replacement & future upgrade, including backward compatibility
  16. manufacturer provides good technical support (hardware & firmware)
  17. security (insurance deductible, theft)

Marine Data Networks

8/7/2017: Updated “Hardware” section to include Rose Point LLC’s announcement, dated today, of “nemo™” “Signal K” device.

There was recently a question on a forum I follow asking, “are there devices that can allow different network technologies to ‘talk to one another.'”

Just understanding that question requires some knowledge of computer and network technology.  The question is asking if there is the capability to share data created by a software application on one computer with one or more software applications running on another computer.  That capability is actually extremely complex to achieve.

Networks are the “roads” over which digital data travels between computers.  The Internet is just a large and complex “highway system” for digital data travel.  Just as “roads” range in size from dirt trails to interstate highways, computer “networks” range from slow, limited in capacity to very fast and enormous capacity.  Just as Interstate highways can carry more traffic than city streets, some network designs carry more data than others.  Cars and trucks travel on highways.  “Units” of data travel on networks.  Each unit of data on a network is like one car on a highway, in that it can have a different destination than the unit in front of it or the unit that follows it.  Just as there are many sizes/shapes/brands of cars and trucks, there are many different formats for individual units of digital data.  Trains travel on a specific road bed called “tracks,” while cars travel on a specific roadbed called “pavement.”  Networks are designed to handle one – and only one – particular format-type (Syntax) of digital data, so a different unique network is required for each different format-type of data.

Increasingly, the navigation equipment found on pleasure craft are actually computers running operating systems (usually Linux) and software applications (called “firmware”).  Chart Plotters, AIS receiver/transponders, VHF Radios and autopilots are all special purpose computers.  These devices are connected together with network connections consisting of pairs of primary wire, coaxial cable, multiplex cable varieties, or radio waves in the case of Bluetooth and Wi-Fi.  They have imbedded operating systems and run apps of functionally-specific “firmware” which exchanges various kinds of information (depth, heading, course, speed, cross-track error, position, temperature and many more), back and forth among the components of the navigation suite.

So the question, “are there devices that can allow different network technologies to ‘talk to one another,'” is very complicated.  The real answer is neither “yes” nor “no;” the real answer is: “maybe;” “sort of;” “sometimes;” and “it depends.”

Over the past 15 years, the navigation electronics designed for and deployed on pleasure craft has exploded in function and complexity.  There are several excellent and highly competitive marine electronics manufacturers, each with worldwide markets, producing navigation equipment components and systems.  There are also companies specializing in developing sophisticated vessel monitoring and accessory equipment.  That explosion of marine function and technology has been accompanied by a similar explosion by technology companies that manufacture portable, durable, highly functional general-purpose consumer electronics and computing products.  There are many general-purpose computing equipment choices today that boaters did not have as recently as 5 years ago.  It’s highly likely the current rate of development will only accelerate in the near term future.

Whether in the realm of specialty navigation equipment or general-purpose equipment used to support navigation tasks, there are several technical realities that underlie the complexity of the navigation electronics market.  Key technology areas include:

  1.  data formats and data-exchange networks,
  2. capability of hardware devices, including designs for backward compatibility, and
  3. availability and capability of software applications, whether in the form of device-specific  firmware, smart phone apps or PC operating systems with application software, that all need to interoperate.

As youngsters learn to play various sports, they must learn the terms that go with the game.  In baseball, for example, the young ‘un must know what a “ball” is; a “bat;” a “base;” a “diamond;” a “hit;” a “strike;” a “foul;” an “infield fly;” an “umpire.”  In a discussion of digital data and networks, there are terminology and concept basics that need to be understood.   For this article, following are some of “the basics:”

  1. Interoperability – The ability of a buyer to purchase equipment from different manufacturers and be able to install that equipment into an existing suite of equipment with confidence that it will all work together.  When many different manufacturers make products that overlap in capability and are intended to provide the same functional capabilities in the same target market, “interoperability” is an essential requirement of the buyer/end user.  “Interoperability” must be designed into the equipment.  These designs are implemented by adherence to various industry standards and the architectural protocols of the communications network that the equipment utilizes.
  2. Syntax – The specific sequences of control information and user data that make up units of data traveling in a particular network.  In NMEA0183, data units are called “sentences;” in NMEA2000, data units are called “Parameter Group Numbers;” in Ethernet, data units are called “packets.”  The specific format of these units of data are all different from each other, but the construction of each kind of data unit follows very specific architectural rules.
  3. Protocol – Any defined, standardized scheme used to pass data between devices by which the data sent from one device can be received and correctly interpreted by another device.
  4. Simplex – A one-way (uni-directional) communications link between a device that sends data (like a compass sending a heading) and another device that receives data (like a chart plotter displaying a compass heading).  This technology can use a single pair of signal wires.
  5. Duplex – A two-way (bi-directional) communications link, like a telephone conversation.  In digital communications, this technology typically uses three wires, Transmit Data (TD), Receive Data (RD), and signal ground
  6. Serial – Data that is transmitted bit-by-bit, like typewritten words.  Think of a keyboard (typewriter), where the words of this article were created serially, letter-by-letter.
  7. Parallel – Data that is handled in frames of predetermined length.  The two most familiar items here are “32-bit” and “64-bit” operating systems.  What that means is that the internal processor chips and “motherboard” can handle either 32-bits or 64-bits at a time, instead of just one single bit.  Parallel operations add cost but speed up computer and network throughput speeds.
  8. NMEA0183 – A “first generation” marine serial data communications protocol standard of the National Marine Electronics Association (NMEA), used to enable interoperability between other NMEA0183 made-for-purpose navigation devices, including devices made by different manufacturers.  Furuno, Garmin, Raymarine, Sitex, etc, etc. all make GPS receivers, depth sounders, chart plotters, autopilots and weather instruments that can share their data (Interoperability) on a client’s boat because they all follow the same data architecture standard.  This network uses a pair of signal wires (data signal + and electronics ground).
  9. NMEA2000 (N2K) – A “second-generation” marine serial data communications protocol standard used to enable interoperability between N2K devices made by multiple manufacturers.  Faster and more extensive than its NMEA0183 predecessor standard, N2K includes support for data from accessory equipment (engine operating and performance data, battery monitoring data, bilge pump and tank level monitoring data, and more).  This network uses a 5-conductor cable with standardized connectors.
  10. CanBUS – “Controller-Area Network Bus,” is the technology used by the “computerized controllers” found in modern cars and trucks, worldwide.  N2K as used in marine applications is a CanBUS-compatible spin-off of the parent CanBUS technology platform.
  11. Ethernet – The full-duplex networking protocol standards (wired and wi-fi) used by general-purpose computers to exchange data over the public Internet.  The wired form of this technology uses Category 5 or Category 6, 8-conductor cable with RJ-45 terminal ends.  The wireless form of this technology uses two segments of the radio frequency spectrum.
  12. Multiplexor – A simplex (one-way) device that can monitor and forward data passing through NMEA0183 and/or N2K networks, at a minimum.  Some can also include Raymarine Sea Talk network data and Furuno NavNet data.  Multiplexors are designed to bridge data to another network and convert the data format so that it can be used in another kind of network (ex: NMEA0183 to Ethernet).  Conversion of data from one network syntax to another is a function requiring firmware intelligence.
  13. Signal K – An emerging full-duplex (two-way) technology that can convert data between NMEA formats and general-purpose Ethernet formats used by general-purpose computer networks.  This extended function allows the otherwise non-compatible NMEA networks to interoperate with laptop computers, tablets and smart phones using Ethernet (wired or wi-fi) communications networks.

Anyone who has ever read an advertising or marketing brochure for a marine navigation product has been faced with an array of technology terminology (“techno-babble”) like the above.  The “techno-babble” is often confusing, even confounding.  “It sounds wonderful, if I only knew what they were talking about!”  Adding to the confusion, each manufacturer has its own terminology for its features and capabilities.  Furuno has “NavNet.”  Raymarine has “SeaTalk.”  They are the same things by different names.  The manufacturer-specific marketing “techno-babble” adds to the complexity of comparing the capabilities of equipment from different manufacturers.

Data Networks and Data Exchange:

Interoperability is not necessarily a goal of marine navigation equipment manufacturers.   Garmin International has a corporate policy to keep much of their data proprietary.   For other manufacturers, that makes designing for interoperability with Garmin equipment difficult or impossible.  For example, Garmin does not share their autopilot control data syntax with Rosepoint LLC, the developer of Coastal Explorer navigation software.  Thus, Coastal Explorer cannot load route data into Garmin chart plotters.  Garmin’s goal is to “incentivize” buyers of their equipment to stay brand-loyal, since only other Garmin equipment can fully utilize Garmin proprietary data and capabilities.   Conclusion: Garmin doesn’t want true interoperability with other equipment manufacturers.

NMEA0183 (simplex) and NMEA2000 (“N2K”) (full-duplex) are communications network standards for two types of serial networking technologies.   Figure 1 shows the NMEA0183 network model:


Figure 1: NMEA0183 Simplex Network Model

Figure 2 shows the NMEA2000/CanBUS network model:


Figure 2: NMEA0183/CanBUS Full-Duplex Network Model

In an NMEA0183 network, the data units that travel the network are called “sentences.”   In an N2K network, the date units that travel the network are called “Parameter Group Numbers,” or “PGNs.”  The names aren’t important to the average boater.   What is important to know is that these two types of digital data packaging are not compatible with one another.

Within the two NMEA data standards, there are specific sections that provide for manufacturers to use proprietary data syntax.   Several manufacturers, including Garmin, Simrad, Raymarine, Stowe, the Brunswick Corporation, Mastervolt and others, use proprietary data for at least some of their device functions.   If a manufacturer chooses to use proprietary data for any given function, that function may or may not operate correctly in a network involving equipment made by another manufacturer.   More likely, most of the design features will work, but one particular feature – or feature subset – may not.   If that feature isn’t important to the buyer, nothing is lost.   If that feature is important to a buyer, well then, there will be disappointment.   It is not always possible to know in advance if that will happen in any given mix of equipment from multiple manufacturers, so the reality is, there is no absolute guarantee of interoperability.  Adding to the complexity of the technologies is the fact that equipment features and functions change every year as new gear rolls out.  It’s often good advice to stay with a brand if that brand meets your needs.

N2K is an “evolutionary descendant” of another communications protocol called CANBUS (Controller Area Network).   CANBUS is the networking technology used worldwide in automobiles and trucks.   CANBUS is a very fast and very reliable full-duplex serial network.  On boats, it allows modern diesel engine performance monitoring data to be included in an N2K network.  So for example, a marine chart plotter may have the capability to display Cummins or Caterpillar or Volvo engine operating and  performance data.

With the N2K and CANBUS standards, there is no native provision for an interface to an Ethernet network as found on a general-purpose consumer client devices (Server platforms, PCs, tablets, smart phones).   The World-Wide networking standard for general-purpose clients is IEEE 802.11 a,b,g,n wired Ethernet or IEEE 802.3 Wireless Fidelity (wi-fi) Ethernet.   Some marine manufacturers are in the process of adding Ethernet capability to their equipment, as a option for proprietary features/functions if not as a backbone communications network.   Anyone with a requirement to use a general-purpose client device within the Navigation suite will need a way to interface to the NMEA incompatible networks: NMEA0183 and N2K to Ethernet.  Check carefully on any device you purchase that has Ethernet built-in.  It may not be there to support interoperability with general-purpose client computers.


NMEA0183 is a simplex and serial network technology.   The incoming port to a device is known as the “Listener.”  The outgoing port from a device is known as the “Talker.”   Talkers cannot listen, and listeners cannot talk.   By design, an NMEA0183 network is limited to one, single “talker,” and about 4 – 6 listeners.   On most boats, even a “basic” navigation suite of compass, GPS, chart plotter, depth sounder and DSC VHF Radio will need several NMEA0183 networks to function as an integrated system for the user.  Both as new installations and for equipment upgrades, these networks can be a challenge to lay out, can be hard to expand in stages, and will require careful planning and forethought.   Figures 3 is a view of the five NMEA0183 networks I have installed in Sanctuary:



Figure 3: Sanctuary NMEA0183 Networks

Most marine instrument hardware today is made with both N2K and NMEA0183 built-in the unit.   The NMEA0183 interface supports backwards compatibility with older devices that have only an NMEA0183 interface(s).  Today, manufacturers add both NMEA0183 and N2K interfaces to most products in order to support an upgrade path from the old technology to the new.  This allows buyers to add devices with the faster, newer, more functional N2K networking technology in small and affordable increments.  Many – but not all – marine hardware devices support two NMEA0183 listener ports and two NMEA0183 talker ports in addition to an N2K port.   These devices can listen to incoming data on one incoming NMEA0183 listener port and spit it back out again (forward it) on an outgoing talker port.  In that way, data can be bridged to a second NMEA0183 network.   Specific data that can be forwarded is a function of the individual device.  Not all devices can forward all data.

Today, there are devices called “multiplexors” that can translate network data formats into formats needed by other network technologies.   Multiplexors can “listen to” NMEA0183, N2K, Furuno NavNet and Raymarine Seatalk networks and translate that variety of data into Ethernet formats that can be used by a computer or tablet.  Multiplexors can also translate NMEA0183 sentence data into PGN format and forward that data to an N2K network.   Most multiplexor solutions today are simplex (one-way), from the navigation suite to the PC/tablet.   Figure 4 shows the fully integrated suite of equipment aboard Sanctuary, including NMEA0183, N2K, the multiplexor and Wi-Fi.


Figure 4:  Integrated Suite of Equipment, Including NMEA0183, N2K, a Multiplexor and a Wi-Fi Feed For Use By PC and Tablet.

Today in 2017, there is a new development initiative underway.  It is an evolutionary descendent of existing communications network technology, not a new communications protocol standard.   Called “Signal K,” this is being lead not by a manufacturer, or a group of manufacturer’s, but rather a private group (open-source) of software developers.   Signal K is intended to be a full-duplex (bi-directional) solution.  That is, the Signal K hardware (gateway) will assemble NMEA0183 and N2K data and forward it via Ethernet protocols to a PC or tablet, and will receive Ethernet packets from from a PC or tablet and translate that data into NMEA0183 or N2K formats.   The idea is to create an full-duplex network technology platform that truly provides full interoperability.  The developers of Signal K claim that this solution will support Nobeltec, Rosepoint, iNavX, OpenCPN, MacENC, Polar Navy, iSailor, Navionics and other software applications runing on general purpose computing platforms (Servers, PCs, Tablets), all wirelessly via wi-fi feeds.

One such physical gateway is called iKommunicate.  The iKommunicate solution is, in 2017, an emerging technology.  Flash: today – 8/7/2017 – Rose Point Software announced their new “Signal K” gateway, called “nemo.”  Information on “nemo” is available here:  These devices are really highly specialized computers.  They are analogous to the Small-Office Home-Office (SOHO) Ethernet routers that are familiar to most of us.  They don’t do a lot, but what they do, they do very fast and very well.  In the case of iKommunicate, they are data translators, translating between the syntax of data arriving and leaving via different network protocols.
With a multiplexor solution, a computer or tablet application can listen to GPS position data and compare it to a pre-planned route installed on the computer.  But a multiplexor is a simplex device, and cannot talk back to the network, so cannot provide control information to correct the course via the boat’s autopilot.   With the Signal K solution, application software running on the Laptop or tablet would be able to control and correct an off-course condition via the full-duplex Signal K network bridge.


In order to monitor, control and correct for dynamic situations and asynchronous events that occur on the water, a PC or tablet software application solution that has the needed intelligence and decision-making capabilities is also required.  The network alone is not enough.  Today, there are very few software applications that can do that, and NONE that I know of that can do it for all navigation functions.   The two most popular tablet apps – Garmin Blue Chart Mobile and Navionics – can’t do any of this.   MacENC on Mac OSX can do some functions for Mac users.   Coastal Explorer on Windows can perform some functions.   SEAiq is available for iOS and Android Tablets as well as Mac OSX and Windows PCs.  SEAiq can do some driving.   Consider though, if Garmin will not release the syntax of proprietary data to Rosepoint or SEAiq developers, then the apps cannot fully support these manufacturers devices.


So, yes, Virginia, there are devices that can allow different network technologies to “talk to one another.”   But, there’s more to it than just talking.   Just having the network is not enough.  Consider this scenario: put three people in a room, one a speaker of only Mandarin Chinese (syntax), one a speaker of only Arabic (syntax), and one a speaker of only English (syntax); yes, they will be able to talk at one another, but they will not understand one another.   Intelligence is needed to provide translation and understanding.  That is very much what exists in the navigation networking and data realm in 2017.  Any data converter or software application solution will need to understand and translate all three languages (data syntax) in all application areas.

Today, as in the early days of computers, end users of nav equipment must understand more of the technology than they would like to have to understand.  In 1995 or so, my neighbor ran a home-based medical transcription business.  Just to type dictations and send the finished transcriptions to the hospital medical records department, she needed to know a great deal about Windows and network connectivity, for which she had neither background, training nor inclination.  That’s how it is today for navigation electronics on pleasure craft.

Watch this space, though.  In a relatively little time – even today at the high end – we will have equipment that fits into systems, introduces itself as plug ‘n play, and just works.  We will have software apps that allow us to take advantage of all of the features the manufacturers design into their equipment.  And, we will be using PCs instead of made-for-purpose equipment, because it is both less expensive and more functional and flexible.  Were it not for the lack of full-feature software, I would be using only my iPad for navigation today.  As that gap closes, it may well become an all tablet world.

Data Security and the Internet

Although a different technology study from connectivity and networking, the security of data connections in a wireless network is a serious concern for users of any kind of mobile connectivity platform.  This is one of the most complex and jargon-prone areas in the discussion of small, mobile platforms like the SOHO networks found on boats and RVs.  I mean to keep it as simple as possible!

There are no data security measures that will stop a determined, professional hacker with unlimited resources: China, Russia and the NSA, for example.  However, simple SOHO security measures minimize the chances that an amateur hacker can gain access to your SOHO network and personal data.  These simple precautions minimize the chance that malicious software could infect your systems and launch attacks on others from your network.   They demonstrate your intent to protect yourself, and therefore preserve your legal right to pursue compensation for unauthorized use of your system and its resources.   Some courts have ruled that if computer owners fail to take steps to protect their systems, they can not sue for damages caused by unauthorized use of their network or attached client devices.

“Easy” Security Stuff (Wi-Fi):

By far and away the most “dangerous” thing many cruisers do with their PCs is go to public places to get access to “free wi-fi” (Starbucks, Barnes ‘n Noble, local library, marinas, municipal docks and others).  There, they connect directly into an “open” AP to read email, browse the Internet, or do online shopping in plain, open-text browser (HTTP) connections.  These public APs are, by definition, untrusted, untrustable and untrustworthy.  On these open networks, your PC becomes a peer to all of the other connected client computers.  You have no idea who else might be on with you.  Your PC is directly exposed to “file share” risks, “spoofing” and “Man-in-the-Middle” attacks.  The openness of the setting creates the opportunity for “sniffing” (eavesdropping) and “key-stroke logging” threats.  In public “coffee house” locations, security threats are possible, common and even likely.

Use of cellular telephone system modems for Internet access is, of course, not free, but it is “easy.”  The very nature of the technology used on cellular telephone systems makes it inherently more secure than Ethernet wi-fi.  Ethernet wi-fi uses fixed frequency, permanently-assigned radio “channels” in  public radio bands to exchange data.  Once a wi-fi connection is established, it remains present on the same radio channel for relatively long durations.  In that environment, “sniffing” (eavesdropping) is technologically easy and convenient for amateur hackers.  Cellular system data exchange uses a mix of “Frequency Hopping Spread Spectrum” (FHSS) data exchange technologies.  Data exchanged on FHSS links consists of sub-second transmissions over ever-changing frequencies in a randomized sequence.  That effectively “scrambles” the data to anyone trying to intercept it.  The technology requires significant knowledge and specialized equipment to eavesdrop successfully.

SOHO router and range extender manufacturers assign default SSID names and default administrator IDs and passwords to their products.  For example, new Linksys devices have an SSID of <linksys>, and new NetGear devices may have an SSID of <NETGEAR> or <wireless>.  When scanning for APs to which to connect, SSID names are what is seen by the scanning program.  With the default SSID name, default Administrator ID and password pairs are easily found on the Internet.  Skeptical?  Take a look here:  So, I strongly suggest owners change SSID names and default IDs on SOHO routers.  Definitely, absolutely change the administrator password away from the default password.  Casual passersby as well as amateur hackers could easily gain access to your SOHO router if you have not taken this simple precaution.

Establish an “encryption method” and password for wi-fi access to your SOHO router.  This is accomplished via the “wireless security” settings of the router’s firmware.  Successful wi-fi client connections will then have an encrypted link for data exchanged between themselves and the router.  Requiring a password causes the router to challenge anyone attempting to establish a wi-fi connection to the router.  That password challenge prevents, or at least delays, unauthorized persons from successfully being connected as a client.  If a hacker with nefarious intent were able to get connected to the router – for example, while sitting on a bench on the Riverwalk adjacent to where the boat is tied up, or from a nearby resort condo, coffee shoppe or boat – that intruder would be a peer on the private LAN of your router.  That exposes you to surreptitious consumption of internet bandwidth, unknown and unexplained, for which you may well be paying a use-based subscription fee.  Worse, perhaps, is that every legitimately connected client device is exposed to the possibility of actual data theft.

“Wired Equivalent Privacy” (WEP) encryption is no longer considered to be a secure technology, but  it’s still better than nothing, because time and effort is needed to get past it; much like locking your car doors.  All newer router firmware and client device operating systems now support “Wi-Fi Protected Access” (WPA), which is more secure than WEP.  Still more secure is WPA2.  The greater the number of characters in an encryption key, and the more random in composition, the more secure it is.  Remember, this step encrypts only the wi-fi link between the client device and the onboard SOHO router.  It does not encrypt data on the outgoing link on the WAN side of the router.  Additional techniques – discussed below – encrypt the connection from endpoint-to-endpoint.

Progressively More Advanced Security Stuff (Wi-Fi):

Between the extremes of not having any data security and having almost total data security is a progressive range of options based on the risk tolerance you might be willing to accept as an individual.  On your boat, you have “situational awareness” of potential data security threats.  That is, you know if you are on the public wall in downtown Savannah, Nashville or Ottawa.  You know if you’re at Delegal Creek on rural Skidaway Island, GA.  You know if you’re in a crowded municipal mooring field or alone in a rural anchorage.   Yes, there is always “some risk” of data security exposure, but if the personal risk is low, I feel I have acceptable choices.

The first level of intermediate protection is simply to remain on your boat to use your own local system with “Network Address Translation” (NAT) enabled in the router.  NAT is a simple one-size-fits-all “firewall.”   NAT will always reject incoming traffic that does not pair with a previous outgoing request generated by you.  The minutia here is tedious and unnecessary.  NAT generally prevents “trolling” requests.  NAT is “spoof-able,” but in the absence of a known return on his or her time, a hacker is unlikely to invest the effort and technology that spoofing requires.  If interested in the detail, ask your 13 year-old grandchild to show you how it’s done.  Or perhaps, ask Target or Neiman Marcus…

If the browser you use allows for supplemental security and firewall “plug-ins,” and they are available, use them.  Plug-ins extend and customize browser capabilities.  Plug-ins are browser specific, and can be located by functional capability with a DuckDuckGo search.  Search DuckDuckGo for <firefox security plugin>, for example, and see how many hits you get.  Firefox’ security plug-ins will help in any Firefox-based data exchange.  They will also catch many nefarious sites to which you might accidentally link or be “redirected.”  At a minimum, in your browser’s “settings” or “preferences,” set your browser to notify you of “redirects.”  I set mine to “disable.”  If a site redirects you to another site, you’ll get a chance to approve that action.  Only very complex, trusted sites will ordinarily do that, and your browser will remember any that you actually wish to permit.  In ordinary Internet browsing, you do not want unknown redirects.  That’s a very typical way that user email accounts get “hacked” and contact data gets stolen.

PC clients absolutely should run pop-up prevention, firewall, anti-virus and adware avoidance software; especially so on Windows PCs!  There are a plethora of aftermarket applications for Windows.  That’s one of the reasons I’ve abandoned Windows in favor of my Mac and OS X.  Many modern routers have sophisticated, configurable built-in firewalls.  These are very useful in filtering out undesirable traffic and blocking it.  Router firewalls are normally enabled by default.  Leave them enabled.  They are configured in the router’s firmware via the browser.

All routers have a built-in security facility called “MAC Address Filtering.”  This is a facility that has the effect of “pre-authorizing” specific client devices to enable them to connect to the router.   By default, it is disabled in the router firmware.  Use of the facility is a two-step process.  First, the MAC address(es) of the specific client device(s) you want to allow to connect must be entered into the MAC Address Table.  Second, the facility itself must be enabled.  Do it in that order, or you may lock your computer out of the router.  Once set-up, the router will only allow wi-fi connections for client devices that are listed in the table.  Even if a newcomer knows the challenge password, the device will not be connected to the router unless its address is also in the router’s MAC Address Table.  There is some administrative “overhead” workload associated with MAC Address Filtering.  In SOHO networks that rarely or never encounter newcomers, this function offers very good control of transient clients with minimal ongoing administrative overhead.  In networks that frequently encounter visitors or other newcomers, the overhead can be significant.  The device’s “MAC Address” will be printed on labels on modems, routers, PCs, tablets, printer/scanners; indeed, any device that can be attached to a network.  It can also be found on PCs with the <C:\ ipconfig> command on the DOS Command Line in Windows , or the <ifconfig> command via the “Terminal” utility on the Mac.  An example of the appearance of a MAC addresses is: <00:07:fd:ea:05:bc>.

All banking and investment institutions, and virtually all e-commerce sites, use “secure browser” (HTTPS) web site sessions with “Secure Sockets Layer” (SSL) encryption technology.  SSL is the standard security technology for establishing an end-to-end encrypted link between a web server and a client’s browser.  SSL ensures that all data exchanged between that specific server and your browser is encrypted and secure.  SSL is a computer industry, cross-platform security standard which is used by millions of websites for protecting online transaction exchanges with their customers.  Use of SSL is automatic and requires no user enablement.  SSL provides 128-bit encryption of all links between origin endpoint and destination endpoint.

“FireSheep” is a well known nefarious Firefox browser plug-in that allows “hijacking” of account passwords in 32-bit, open HTTP browser sessions.  In response to “FireSheep” and other “sniffing” threats, Facebook, Twitter, Google web applications (mail, docs), AOL and many other sites switched to the default use of secure HTTPS  with SSL.  HTTPS is optional on Yahoo.  Many sites that were not using SSL have now made that transition.  To help end users further close the window on sniffing risks, a free “browser security plug-in” everyone should consider is “HTTPS Everywhere,” located here: (  The tool is a security plug-in for the most popular 3rd party browsers (mine is Firefox; note that there is no version of HTTPS Everywhere for Internet Explorer).  The plug-in forces the browser to use the secure HTTPS protocol instead of the open HTTP protocol.   Because the secure HTTPS protocol does not always behave in a manner that is compatible with the open, unsecure HTTP protocol, HTTPS Everywhere might introduce “unexpected behaviors” that are visible to the user.   Read the HTTPS Everywhere FAQ before installing, but I use it – and like it – for casual Internet browsing protection.

Finally, we come to the “Virtual Private Network” (VPN).  Although I have discouraged using any public, open wi-fi connections, I know there are those who absolutely must “live on the edge.”  The only way to ensure data security and privacy for those few is to install and always use a VPN subscription product.  VPNs (also called “secure tunnels,” or “tunnels”) are the opposite logical extreme from no security at all.  VPNs encrypt all data exchanged over all link hops, whether wi-fi, cellular or wired, from their origin endpoint to their destination endpoint.  VPNs do carry some user complexity and some platform performance overhead.  For most users, I would expect the learning curve to be relatively short.  Any performance impacts should be of minor significance unless CPU usage is otherwise very high due to concurrent workload.

A subscription to a VPN service includes a VPN security server paired with a client security application installed on the client’s devices.  Detailed install instructions will come from the VPN service provider.  A security client application needs to be installed on – or a compatible VPN function provided by – each locally attached client device: that is, each and every PC, each and every tablet.  VPN vendors use a variety of encryption technologies.  Some are better than others.  There are “free” and “fee” VPN services.  Fee VPN subscription pricing varies over a considerable dollar range.  Client data (that is, your personal information, passwords, browsing content, financial information, etc.) is visible to the system administrators of your VPN vendor.  In vendor selection, due diligence is necessary (required) around vendor reputation and the pros and cons related to the encryption technology the vendor uses.

Some reading this article may still be working (hopefully not fully captive ashore!) and have access to employer VPNs.  That’s fine if the employer’s system use policies permit use of their computer and network facilities for personal activity.  Remember though, enterprise VPNs are not there to protect you or your personal data.  Enterprise VPNs are installed for the purpose of protecting the business’ internal, secure enterprise network from hackers that might gain access by hijacking validly established connections originating outside the secure network.  Usually, by hijacking an authorized employee’s legitimate connection.  Remember also, the employers system administrators can see and monitor user data and browsing activity, if they choose to track it.  Caveat emptor.  Avoid, for example,  criticizing the company or your boss on an aliased Facebook account from the company’s VPN!


Wireless IP Cameras to Monitor Engine Room

Boaters are universally warned to be diligent about performing engine room checks to identify developing problems before they become serious. So now, truthfully, are you methodical about doing hourly checks? Every 2 hours? Do you perform engine room checks when sea state is up and the boat is “rockin’ ‘n rollin’?” Do you ever find yourself wondering, “what’s going on down there,” when seas are “rockin’ ‘n rollin’?”

I admit, I am not as diligent about engine room checks as some folks are. I am not as diligent about engine room checks as some folks tell me I should be. For better or worse, I have been somewhat laissez-faire about this responsibility. I am not entirely free of anxiety, but my anxiety is often not sufficient to motivate me to move to the engine room from the comforts of my helm chair.  Some might think of that as “risk-taking behavior.”  I haven’t had any serious incidents in 10 years and 42K miles aboard, but I could be living on borrowed time.

I am a technology guy. I have written about my laptop and tablet computer choices, my on-board router, my wi-fi range extender, my cellular modem choice and my AC electric energy monitor. I have written about getting real-time data from my navigation instruments to my laptop and tablet via my NMEA multiplexor.  So I took a look at using a technology approach to engine room checks?

Because I already have a router aboard, adding new wi-fi features and functions is easy and straight-forward. For some months now, I have though that mounting a couple of wireless Internet Protocol (IP) cameras in my engine room would reduce my risk and my anxiety. IP cameras are a known quantity. IP Cameras have been available in business and home markets in security and baby monitoring applications for some time. Why not put one or more in the engine room to monitor certain key functions, such as the engine alternator’s voltage regulator, fuel filter(s) or the output shaft and its packing gland or dripless shaft seal?

Recently, I found Foscam FI8918B/FI8918W wireless IP cameras available at <; for a very attractive $50 price tag. I couldn’t pass that up, and I ordered two cameras. These wi-fi cameras installed easily. They produce still photos and full motion video at a resolution of 640 x 480, so very adequate for online viewing or Internet blog posting (see below). Images and videos are automatically stored for later viewing in the iOS device’ photo album. The infrared CMOS image capture technology produces acceptable detail even if the engine room lights are off (the normal condition).

These cameras have built-in web servers.  They are are accessed and configured via any common web browser (Firefox, Chrome, Safari, IE). Any computer, tablet or cell phone with any browser can access and configure them. The cameras can be continuously panned in every direction. They are rated for temperatures up to 140ºF, so are fine in my engine room. My version of the camera requires 5VDC; mine get that with 90-to-250VAC power “bricks.” They have a preset function that allows for automatic pan/tilt to a predefined field-of-view, such as “filter 1” or “filter 2” at a screen tap.  They support sound via a built-in mic, but I haven’t played with that in my application. Built-in motion alarms are available. The cameras can be set up for remote access, via DDNS over the Internet, which would enable monitoring from offsite locations. A very nice package for $50.

The cameras do have some minor limitations. These cameras are 0.3 megapixel units, so resolution is limited.  The 67º field-of-view is very wide, so they must be mounted nearby to monitor small objects. There is no way with these cameras to adjust color rendition, and I have observed that reds are washed out and contrast adjustment is challenging. I also note that when the engine room lights are off, the infrared does not pick up the yellow and red warning bars on my fuel system vacuum gauges. However, I do not find any of these limitations to be serious in my application.


Fuel manifold showing fuel vacuum gauges

To the left is an image of my fuel manifold taken with one of my IP cameras and captured via Firefox on my Macbook Pro. This enables me to monitor my fuel vacuum gauges while underway.  Interestingly, with the engine room lights off and just the infrared imaging, I can see the internal structures in the fuel bowl quite clearly.


Drive shaft showing transmission coupling and packing gland

To the right is an image of my drive shaft and packing gland (transmission and shaft coupling toward the bottom, packing gland toward the top).  This image was from the second IP camera, also captured via Firefox.

In Apple’s iTunes store, I found a $6 iOS app called FoscamPro. The app supports both the iPhone and my iPad. The app renders several camera images at the same time. Note, this app in not developed of marketed by the camera manufacturer. Shop carefully here. There is a free app that had very poor reviews, and although it appears to be from the camera manufacturer, reviewers say the app is privately developed and the logo is pirated. I dunno.  In any case, the FoscamPro app seems fine in my environment. Since I use the iPad on my flybridge, I find being able to see multiple images concurrently to be quite convenient.

Following is a screen shot of the FoscamPro iOS app on my iPad:


FoscamPro app on iPad showing concurrent rendering of two camera images

Update 9/22/2014: I installed a third camera to monitor my Balmar alternator voltage regulator.  Following is a picture of what I see now:

FoscamPro home screen showing multiple IP cameras monitoring engine room systems.

FoscamPro “home” screen showing multiple IP camera images monitoring engine room systems.

photo2To the right is a view of the FoscamPro app portlet containing the image of my Balmar ARS-5 Voltage Regulator.  Just while testing the camera installation, I observed strange regulator behavior that needs follow-up with Balmar technical support.  The great benefit is that I can now track this system in realtime, while the engine is running, without close proximity to moving parts.  Prior to installing the camera, the regulator’s location in the engine room made it virtually “impossible” to observe while underway.

I definitely do not suggest that these wireless IP cameras are completely equivalent to an in-person engine room check. The infrared capability of the camera will highlight hot-spots, but will not measure temperatures. It cannot see everything that an in-person engine room inspection would disclose. However, for visually spot-checking key areas, this is a good solution for us aboard Sanctuary, and particularly for those who might be disinclined to move around the boat in heavy sea states.


Computer Connectivity and Data Security

Significant update: Managing MBR95 Device Connections, 1/23/2016


Most cruising boaters want to “stay in touch” with family, friends and business colleagues who remain captive ashore.  Cruisers want to exchange email, research exciting ports-‘o-call, post exploits and pictures of sunsets to social media, blog, shop and even pay bills, and do all this from remote and exotic anchorages.  The computer equipment found aboard cruising boats varies widely, from a single computer or tablet PC to a complex mix of multiple computers, tablets, printer/scanners, cameras, and more.  Regardless of complexity, US coastal and inland waterway cruisers have only two practical technologies for wirelessly connecting their vessel’s computers to the dirt world.  One is the cellular telephone system and the other is wi-fi technology.  The two technologies are very different from each other, yet under the right circumstances both can provide reliable connectivity at reasonable cost.

Aboard Sanctuary, our connectivity platform is designed to maximize the probability of obtaining a viable connection.  To that end, we have installed both a wi-fi link and a cellular system data link.

Cellular systems offer reliable data connections at far greater distances than wi-fi technology can offer.  Cellular data connections are automatically transferred from cell site-to-cell site as we cruise along, and reconnect automatically if the signal is lost.  These functions of the cellular system provide virtually continuous Internet connectivity in most US East Coast cruising areas, including to a significant distance from land in our infrequent offshore passages.  These benefits are not possible with wi-fi technology.  Furthermore, everywhere we’ve cruised, I have observed that open unsecured wi-fi is less-and-less available.  Thus, I have come to view wi-fi availability largely as an “amenity.”  We installed a wi-fi range extender so that we can enjoy it when it is available, but for our “normal” US near-coastal cruising lifestyle, we cannot and do not rely on having wi-fi available.

This conclusion can be completely opposite in other cruising locales.  US cellular data plans are prohibitively expensive when used in Canada.  There are availability, compatibility and cost issues with cellular data connectivity in the Bahamas.  Inexpensive, sometimes free, access to wi-fi is generally available in these locales, and across the Caribbean.  In that set of circumstances, wi-fi clearly emerges as the preferred technology for cruisers wanting to stay connected.

“Mobile connectivity” and “data security” have been the subject of a number of recent “discussions” on the MTOA Llstserv and other boating sites and fora.  These discussions frequently delve into technology details and contain a lot of technical jargon.  Technical jargon is often used without context, and occasionally misused.  Discussion subjects morph off-topic, and discussion threads become disjointed.  Such discussions are of little value to lay persons with little or no prior knowledge of the topic.  Lay readers interested in the topic quickly become frustrated and lose patience with such discussion threads.

This article is written in two sections:

  1. a basic orientation to CONNECTIVITY SOLUTIONS and the inescapable underlying technologies that apply to a mobile connectivity platform, and
  2. an overview of WIRELESS DATA SECURITY issues, considerations and choice options.

I have tried to write to lay readers who consider themselves to be “novices,” or “beginners,” with computer “stuff.”  That is, those with little or no technical background but who would nevertheless like to have reliable and reasonably secure wireless Internet connectivity on their boat.  I have provided a component diagram that portrays Sanctuary’s connectivity solution.  This article is written so the “beginner” can understand the included diagram and use it as a reference in the future to provide context to other discussions and to identify and target additional learning needs.  My goal is to “put some boundaries” round the topic.  Technical content bits are limited to that which is needed to understand the diagram.  I’ve tried to avoid technical language.  I take some liberties to avoid non-essential technical “minutia.”  Where technical detail is inescapable, I do my best to frame its context and explain the related jargon.


In this article, the term “data” is used to refer to all of the digital messages that move from point-to-point in a network, just  as “vehicle” is a term that refers to the motorcycles, cars, trucks and buses that drive on streets.  Digital message “data” includes account IDs and passwords, word processor files, spreadsheets, email,  photos, videos, web pages, bank and investment statements, ePubs, GRIBs, and many more.  Technologically, Small Office Home Office (SOHO) in-home networks are simple, minimal instances of a network.  They are private “extensions” of the “World Wide Web” (WWW), in the same way that residential driveways are private extensions of our national network of roads and highways.


Connectivity to the World Wide Web (WWW), or “Internet,” is most commonly delivered to a residential subscriber via telephone Digital Subscriber Line (DSL), TV cable, fiberoptic service or satellite dish.  WWW connectivity is also delivered to subscribers via cellular telephone system technology.  Each delivery technology has unique data handling and control formats.  A “Modem” is a device that “translates” utility-unique data formats into the format needed by computers.  Modem devices are unique to, and must be compatible with, the specific type of delivery technology used.  In cellular telephone systems, USB-stick modems (or a tethered cellphone) join individual computers to the cellular network via a cellular two-way radio link.  More advanced cellular “mi-fi” modems include imbedded routers and can attach multiple wi-fi “client devices.”  A mi-fi device makes a cellular network connection that it then shares among attached wi-fi clients.  For simplicity in the rest of this article, I will use the term “client devices” to mean any device that can attach to a network, such as PCs, tablets, printer/scanners, some cameras, game systems, web servers and many others.

Real-time intelligence is required to manage the arrival and departure of transient network connections.  “Operating Systems” (OS) with names like Apple OSX, Apple iOS, Microsoft Windows and Google Android provide the needed intelligence on PCs and tablets.   “Firmware” is OS-like software that provides that intelligence for “smart devices” like routers, web servers, printer/scanners, cameras and others.  In the same way that operating systems reside within PCs and tablets, firmware is built-into its host device.  Sophisticated firmware usually has many user-adjustable settings.  These settings for “smart” devices are accessed and changed via a web browser (Firefox, Chrome, Safari) that resides on a PC or tablet.

“Ethernet” is a term that refers to a family of data exchange technologies.   There are both wired and wireless Ethernet technologies.  Wireless Ethernet connections are known as “Wireless Fidelity” (Wi-Fi) connections.  Ethernet  technologies are worldwide computer industry standards created by the Institute of Electrical and Electronic Engineers (IEEE).  These standards make it possible for an infinite variety of client devices to digitally exchange and share data.  The “wireless” Ethernet standards are IEEE802.11 a, b, g and n; the “wired” Ethernet standard is IEEE802.3.  This may seem a bit of technology minutia, but is mentioned here because these terms appear on product packaging, in owner’s manuals and in Sanctuary’s installation diagram; they are ubiquitous and inescapable.

A “Router” is a made-for-purpose networking device.  In the router function that applies to this article (there are others), the device attaches to a World Wide Web interface (the modem) to share the web with and among multiple client devices.  The router’s connection to the modem is designated as it’s “Wide Area Network” (WAN) port.  The router’s wired and wi-fi client device connections are designated as its “Local Area Network” (LAN) ports.  In some cases, such as cellular mi-fi devices, modem and router functions are packaged together (combined) into a single physical device.

Each client device connects to a network at a unique network address, analogous to a home’s unique postal address.  Setting this up is an inescapable owner configuration detail.  A technology called “Dynamic Host Configuration Protocol” (DHCP) manages assignment of network addresses as client computers “come and go.”  DHCP is a service that runs on both ends of a network link.  Whether wired or wi-fi, when a newcomer arrives on a network, it “checks-in” to the host network by making a DHCP-request to get an address.  The host network DHCP-server at the other end of the link receives the newcomer’s request.  If an address slot is available and client security credentials match, the server assigns the newcomer an address on the network.  Thereafter, the newcomer is a “peer” to all other client devices on that network, and competes with its peers for slices of network access time.

During router setup time, it will be necessary for owners to select and configure some WAN and LAN network “addresses” in “TCP/IP version 4” (IPv4) notation.  The IPv4 address notation appears in various network configuration windows, each of which is unique to the specific operating system or firmware involved.  Skipping much technical minutia, novice computer users will see addresses in the form of four groups of decimal numbers ranging from “1” to “254,” separated by periods.  Device addresses will look, as an example, like this: <>; or like this: <>.  An important detail: the IPv4 standard sets aside several “private” address ranges for uses like home and home-office networks, including <10.nnn.nnn.nnn>, <172.16.nnn.nnn> and <192.168.nnn.nnn>.

Networks can be subdivided into “subnets,” also an inescapable part of SOHO router owner setup.  Subnets are analogous to groups of residences within a postal carriers’s route, like “the 600 block of Ocean Ave.,” or “the condos at 4th and Walnut.”  A “subnet mask” consisting of four groups of decimal numbers ranging from “0” to “255” is used to define the point in the address where the subnet break occurs.  In the example of these two addresses, <192.168.1.nnn> and <192.168.42.nnn>, the first two 3-digit groups are the same, but the third group is different.  A subnet mask of <> means the third group represents two different subnets: subnet “1” and subnet “42.”  With a subnet mask of <>, the address would represent two different devices on the same subnet.  In some User Guides, the notation <> might appear.  The “16” means a subnet mask of <>.  A notation of <> would mean a mask of <>.

Routers use a ”Media Access Control Address” (MAC address) to route inbound digital messages from their superior WAN interface to the intended recipient client device (wired or wi-fi) on their LAN side.  Client devices attach to the Internet with many different network addresses at many different sites.  A MAC address is a characteristic of, and uniquely identifies, each specific wired or wi-fi network port which is able to attach to an Ethernet network.  Just as husband and wife each have unique names that do not change when they move about from place-to-place, each network port on a client device has a unique and permanent MAC address.  The MAC address is the “name” of the device’s individual wi-fi or wired physical network connection.

An “Access Point” (AP) is the upstream end of a two-way radio link, analogous to an on-ramp at an Interstate Highway interchange.  The AP is the portal through which subordinate networks, or client devices themselves, gain access to larger networks.  In wi-fi systems, multiple APs can be present in an end-to-end connection path.  The two-way wi-fi radio built-into a router (the wireless LAN) is an AP for its attached clients.  At a marina, the shoreside device to which the fleet’s mobile platforms connect is an AP.  In public places with “free, open wi-fi” systems (Starbucks, local library, Barnes ‘n Noble, marinas and municipal docks), the AP to which client devices connect is part of the host’s infrastructure.  When visiting a friend’s boat with your PC or tablet, the AP to which you connect is the host’s onboard router.  For an anchored boat, the AP for that mobile platform is any AP ashore (often someone’s home router) that is in-range of the client device’s wi-fi radio.  All APs have names.  By default, APs broadcast these names to announce their presence to nearby wi-fi capable clients.  The AP’s name is known as its “Service Set Identifier” (SSID).  The SSID is analogous to your family name, which identifies family members to others.  In cellular systems, the shoreside AP is a cell tower to which the USB modem or mi-fi device and associated clients attach to the WWW.


The following diagram shows the component parts of Sanctuary’s computer connectivity platform.  All of the connectivity and network elements mentioned above are shown in relationship to each other:

m/v Sanctuary Connectivity and SOHO Network, January, 2014.

m/v Sanctuary Connectivity and SOHO Network, January, 2014.


Wireless radio links are subject to a wide variety of atmospheric propagation and radio interference conditions.  These variables affect the reliability of the link.  Anyone who has ever listened to a short-wave radio broadcast knows how the distant signal alternately strengthens and fades, and sometimes fades into unintelligible noise.  The radio transmitters in marina APs are relatively high-powered and have high efficiency antennae.  Thus, the radio “downlink” from the shoreside AP to the receiver inside a remote client is usually fairly strong.  A connected PC or tablet may show “4 bars” of signal strength, implying a reliable communications link.  However, the wi-fi radio transmitter inside a client device is low-powered, and internal antennae are not highly efficient.  Thus, the radio “uplink” from the client device to a shoreside AP can actually be quite weak.  The AP ashore “shouts” at the boat, but the boat responds to the AP in a “whisper.”  This is like a football coach who shouts at a player who’s fumbled, but the response to the disappointed coach is in a barely-audible whisper.

Signal fade-out and radio interference from any source result in data transmission errors that can make the data transfer performance of a wi-fi link frustratingly slow, or effectively impossible.  Atmospheric and radio propagation conditions vary from season-to-season, day-to-day and hour-to-hour within a day.  Some days (cloudy, rainy) may seem tolerable, even good, but on other days (hazy, hot, humid summer days), effective communications may be impossible.  Radio links are often more reliable during hours of darkness.  Cellular radio technologies operating over medium and longer distances, particularly in rural settings, are subject to similar adverse effects.

A range extender compensates for any potential weakness or radio interference affecting our AP uplink, thus improving the reliability and effective range of our wi-fi data transmission.  A range extender can make all the difference between blissful happiness and total frustration.  With regard to range extender devices, one expert [Dave Skolnick of s/v Auspicious] said: “I see the space as having three big players (Ubiquiti Bullet, RedPort Halo, and Microtek Groove) and a number of more minor players (like Radiolabs). Many private labels like Rogue Wave are relabeled Bullets.”  I quote him here because I completely agree.


Managing the Cradlepoint MBR95 and the Ubiquiti BulletM2HP as a “system” can appear complicated, even “cranky.”  Let me state furthermore, managing any system made up of multiple components from different commercial sources can be cranky.  The more the owner knows about their system and its components, the better the chances of maintaining connectivity.  What I have learned through trial and error is, if the MBR95 has the cellular modem in “connected” status on the <Internet Connections> tab of the router, then the browser can’t see the Bullet, and so users cannot logon to it.  I suspect this has to do with limitations of the MBR95 firmware.

What I have learned to do is ALWAYS logon to the MBR95 first. I start by selecting the <Internet Connections> tab.  There are entries on the connections list for all connections the user has defined. At a minimum, there will be entries for the Bullet and the cellular modem.  There are up/down arrows on the left of the page, so the first thing I do is move the Bullet “up” to the top (highest priority).  Not sure that is necessary, but I do it.  After applying that change, one can wait a couple of minutes for the router to “see” that change. The router will “connect” the Bullet (make it the active Internet connection) and change the modem’s status to “Available.”  My “normal state” is to see one device as “connected” and the other as “available.”  In order to logon to the Bullet from a browser, the Bullet must be in “connected” status.  The browser can’t get to it if it’s only “available.”

If I now wait a bit, the router will eventually detect the change the connection status.  However, I can speed that process along.  On the <Internet Connections> tab, there are checkboxes that “enable”/”disable” each connection.  Instead of waiting for the router to “figure it out,” users can manually change the checkmarks.  Just tick the Bullet and un-tick the modem.  The router will change the connection right then, and the Bullet will wind up in “Connected” status.

Once the router reports the Bullet is “connected,” the computer/tablet browser can see the Bullet Logon page, and the user can logon to it.  At this point, there will not be Internet connectivity, but the wired Ethernet path to the device is now alive and active.

Logon on to the Bullet and select the <Wireless> tab.  That tab has a <Scan> button on it.  Select <Scan> and choose the desired AP.  Then, scroll down to the real bottom of that page (the true bottom may not be visible if there are a lot of APs in the area.)  Enter any security credentials required by the AP and select <Change.>  Then scroll up to the top of the <Wireless> tab, and in the top righthand corner, select <Apply.> Changes WILL NOT take effect unless <Apply> is pressed.  When <Apply> is clicked, the Bullet will re-boot.  It takes a minute or so for that to happen, but once it does, the wi-fi connection to the remote AP should be made, and full Internet connectivity available.


There are two distinct approaches one can take to achieving an installation such as ours aboard Sanctuary:

  1.  A “roll-your-own” solution built from separately purchased commercial components.
  2.  A commercial, pre-configured, packaged solution.

Sanctuary’s installation is a self-installed, self-integrated and self-configured “Do-it-Yourself” project comprised of separately-acquired materials and components.  I chose that approach because I have the skills to handle the “computer stuff” to get the configuration working.  More importantly, over the long term of ownership, it’s my responsibility to keep it working if/when something flakey happens.  My DIY approach makes me thoroughly familiar with the reasons for the design and configuration choices involved.  If Sanctuary takes a lightening splash in the future, I can deal with component fallout at the unit level without having to ship something – perhaps several somethings – back to a vendor for repair or replacement.  Given my personal knowledge and system familiarity, I avoid the inherent costs and delays involved in needing to locate and hire a local professional when something bad happens.

My personal approach notwithstanding, pre-packaged solutions can be a good choice for technical neophytes/beginners/novices.  Range extender packages do not always include routers, so those choosing the packaged approach should contact their vendor-of-choice to be sure everything needed is ordered at the same time.

Specific equipment vendors come and go in this ever-changing and dynamic marketplace.  Please let me know if there are obsolete links found in this article.

Established companies in this market at the date of writing included:

  1. IslandTime PC (,
  2. WirieAP (,
  3. Wave Wi-Fi (, and
  4. Wilson Electronics.  Wilson recently changed their d/b/a name to “WeBoost (”

All of the above offer packages suitable for marine installations.  IslandTimePC has a particularly strong reputation among boaters.  The Wirie AP has the external and internal WiFi radios that are physically mounted  in the same box.  This can lead to co-channel and/or adjacent channel interference, resulting in data transmission errors and retries.  As explained earlier, above, transmission errors result in a performance penalty for the simplicity of “just run power to it” solutions.

Other vendors in this market include “WiFi Solutions – A&A Cruising Equipment,” which has strong buyer testimonials, “5milewifi,” “Bad Boy Extreme,” and “Wifi for Boats.”  In the RV market, also see “WiFiRanger.”  I have no personal experience with any of these vendors.  Years ago, I bought a range extender from “Radiolabs”.  Its performance was acceptable on my Windows PC.  When I upgraded to a Mac with OSX, Radiolabs flatly refused to support the Mac.  They were less than gracious about it.  I simply cannot recommend them as a dependable business partner.  The larger message to Mac users is, don’t buy a product with hard dependencies on vendor supplied device driver software.  If interested in any of these vendors, search them out via (or for those who don’t mind being tracked, you may use as your search engine.

Installation of a router is optional.  A router is needed here only to support concurrent attachment of multiple client devices or other technical reasons.  Some boaters may have neither router nor range extender at present.  In a case where there is only a desire to improve wi-fi link reliability, only a range extender is needed.  Routers which support both wi-fi and 3G/4G cellular interfaces include the Cradlepoint line and pepink’s “Pepwave SOHO.”

For pre-purchase technical consulting advice on these products, I’d suggest contacting Dave Skolnick, of s/v Auspicious.  Dave is an experienced sailor and bluewater cruiser.  He has his own communications business including Internet and HF Radio connectivity.  Dave understands the marine environment, live aboard lifestyle and boater’s communications needs.  He can be reached at, or (443) 327-9084.  Limited pre-purchase advice may also available from the 3GStore ( or PowerfulSignal (  Both stores have Internet testimonials as having knowledge of the needs of mobile users and of having been helpful to beginners.  I have no personal experience with either.


In our diagram, items that require configuration settings at setup time are highlighted in yellow.  Note that there are many, many more settings in the router and range extender firmware than just those shown above.  For all settings not shown above, I suggest starting with the manufacturer’s defaults, which are fine for the vast majority of users.  To configure router and range extender firmware, see the device user guides.  Make note of passwords you change!  You will need them in the future.

Some thoughts on range extender installation and setup:

  1. It is easier to install and configure a range extender by directly connecting to it using a wired Ethernet connection to the computer; that is, temporarily eliminate the router from the system while configuring the range extender.
  2. Once range extender configuration is completed and shown to be working, add the router back into the system.  Then, browse in sequence to the router and the range extender to perform the remaining setup necessary to integrate the two devices.
  3. Perform final testing of the installation with a real shoreside AP.  Make any configuration changes/corrections if/as necessary until the system works as intended.

I have decided against providing screen shots of configuration settings of Sanctuary’s installation.  Since manufacturers periodically release OS and firmware updates to introduce new functionality and fix problems, over time screen shots and configuration descriptions age and become obsolete.  For novices, use of obsolete descriptions for guidance can create more confusion than insight.  Rather than screen shots, I show settings that need to be configured at setup-time, and need to be made compatible.  I show the settings that I have implemented, however I leave it to the reader to review their specific product’s user manuals and implement setup details needed by their own selection of installed hardware.  A thorough, but in 2014 a slightly aged, guide for setting up the Ubiquiti Bullet is located here:

What I’ve done aboard Sanctuary is by no means “the only way.”  Many experienced RVers and cruisers have written detailed descriptions on router and range extender configuration.  Many descriptions include screen shots of firmware pages, albeit mostly no longer reflective of current release firmware.  These articles can easily be found by DuckDuckGo searches.


The purchase price of packaged solutions is generally about twice that of “roll-your-own” solutions, but not terribly expensive in terms of other “marine” instruments and accessories.  “Roll-your-own” solutions range around $150.00 – $250.00 vs. maybe $350.00 – $600.00 for packaged solutions.  Low vs. high in the range depends on whether or not a router is included in the project.  Configuring “roll-your-own” solutions depends on the specific selection of components and vendors.  Based on the components selected, there can be a wide variety of wired and wireless solutions.  With “roll-your-own” solutions, the burden of product selection, installation, configuration and ongoing technical support is completely the responsibility of the buyer/owner.  Each solution has unique configuration issues.  Consult your vendor(s) for details.

For Sanctuary’s SOHO Router, I selected the CradlePoint MBR-95 and purchased the router from the Amazon Marketplace ($125) 1.  CradlePoint router models have features that are particularly useful to RVers and cruisers.  CradlePoint models all support wired and wireless LAN, as well as wired and wireless Ethernet WAN.  They include support for cellular USB modem attachments (Verizon Wireless, ATT, etc).  One CradlePoint feature is “Wi-Fi As WAN.”  In “Wi-Fi as WAN” mode, CradlePoint routers will wirelessly connect to a remote wi-fi shoreside access point, just as a client device would.  By itself, this is a range extender with intermediate transmitter power.  Additionally, if also using an external higher powered Range Extender with a wireless interface, such as the WirieAP, this allows wireless data connection to the AP in the Range Extender.  CradlePoint routers also have a desirable feature called “failover.”  At setup time, the device is configured a default relative priority for the WAN and the cellular interfaces.  The router will automatically switch to the other network interface if either the WAN or cell interface has a usable signal.  If both interfaces have usable signals, it will connect to whichever interface has the highest user-defined priority.

For Sanctuary’s wi-fi range extender, I selected the Ubiquiti Bullet M2 HP.  It is a high power wi-fi link device.  (; $75 (Bullet) + $25 (antenna) + $15 (120VAC Ubiquiti Power Over Ethernet (PoE)) adapter that powers the Bullet.  Version are available for 12VDC use.  All components are available from  Add the small cost for needed Ethernet cabling and miscellaneous mounting hardware.  Note that the Ubiquiti is the hardware platform of choice for many of the “packaged solutions,” so it’s known in the industry to be a reliable and effective device.  I selected an EnGenius model EAG-2408, 8-db wi-fi antenna that physically mounts directly to the Bullet.  That eliminates cable losses that affect GHz frequency antenna feedline installations.  The Bullet gets it’s power over the Ethernet cable, and I use a Ubiquiti PoE-15 power adapter.

1 Post-purchase follow-up report on my experience with CradlePoint’s  “1-Year Unconditional” Factory Warranty.

I am an individual retail consumer/shopper/buyer of a CradlePoint MBR95 SOHO router. Based on two interactions with CradlePoint technical support, I must conclude that customer support for individual buyers does not seem to be a “customer satisfaction” or “customer experience” priority of CradlePoint as a company. CradlePoint technical support is hard to reach and support seems un-enthusiastic at best.

First, the firmware of my router (v5.0.4) does not correctly display connected client devices; specifically, the “Status/Client List” firmware page does not agree with “Network Settings/DHCP Server” firmware page. In March, 2014, I reported that to CradlePoint. I was refused access to an actual tech support rep, but the woman who answered told me show “would ask” about the issue. When she returned, she said tech support had told her that engineering “is aware of the problem and it would be corrected in the upcoming firmware upgrade (v5.0.4).”  It was not.  Granted, this problem is only an annoyance. It does not seriously affect my day-to-day operation and is not a high severity issue.  However, it does make working with multiple client devices more of a challenge.

Second, in July, 2014, I experienced a total wi-fi radio failure with my still within warranty MBR95.  In working through that transaction, I learned that CradlePoint uses highly unusual terms around their manufacturer’s warranty. CradlePoint’s 1-year “repair or replace at our option” warranty is not unconditional.  The principle surprise is, buyers must purchase the product directly from CradlePoint or from one of their “authorized resellers” to be eligible for the warranty.  To me, this just seems to be a policy intended to discourage price shoppers and independent resellers.  For buyers who “price-shop the Internet” for computer accessories, it may or may not be obvious that this policy limitation exists at all. If the buyer is aware it exists, it may be impossible to determine if a low-price reseller is, indeed, an “authorized reseller.”  The result is, any possible future warranty claim will get summarily denied by CradlePoint.  Initially, CradlePoint denied my claim because – in error – my reseller was not listed in their database as an authorized reseller.  Being retired, when not cruising, I can waste my “leisure time” pursuing fairness problems. I contacted and the Amazon Marketplace reseller from whom I bought. I found that the reseller is indeed a “branded subsidiary” of a firm that is a CradlePoint “authorized reseller.”  Armed with that information, I did eventually achieve satisfaction from CradlePoint.  The warranty replacement router is now installed and working very well; maybe better than the original.  That said, I am certain other buyers have not been treated properly under this warranty policy.  Had I not been persistent, tenacious and assertive in pursuing it, I would have been denied the value of my investment. Again I conclude, the “customer experience,” and “customer satisfaction,” is not a priority for CradlePoint, at least in their retail market.  So even though the product functionality is a great match for my needs, the maxim remains: “Buyer Beware!”


Andriod Tablet/Smart Phone apps for Cruisers

As of December, 2013, all of the following apps but one (I think one) are freebies on Google “Play.”  The Android marketplace is better about free apps than Apple’s iTunes business model.  I started out with an Android tablet because of Android’s better flexibility, but the tablet died a pink-screen death.  When it died, I changed to the iPad because it has a wider following of app developers and greater diversity of apps of interest to cruising boaters.  I do still have a Droid X Motorola smartphone.  Here’s what I have found to be the most useful apps on the Android platform:

Nutichart Lite” has the ActiveCaptain database built into it.  EarthNC for navigation is easier to see where you are.  Neither in their free versions are feature-rich as chart plotter apps.  Several “full-feature” chart plotter apps are available for the Android platform.  Most app developers make the apps available free but charge for the charts.  In most cases, the total-cost-of-ownership of the app and chart paks are quite expensive.  This is a place where SEAiq USA on the iPad, for $10 and free NOAA/USACE charts, has it hands down and sideways over anything else.

ActiveCaptain “Companion” was released in 4Q2013.  The initial release is somewhat limited, but offers hints of good things to come.  In general, there are far too many hazard markers in the ActiveCaptain database, and far too many that are not real hazards, so I found it to be of limited usefulness in it’s current iteration.  That said, it has great potential usefulness as features roll out in the future.

Marine Traffic” is a passable AIS monitor for boaters located in or near population centers.  It relies on ground stations that receive AIS messages and forward that information to their web servers.  It works well and is reliable in NY Harbor and on the upper Chesapeake Bay; that is, locales where many forwarding stations are located.  It is unreliable/inadequate for the St. Lawrence Seaway and less populated areas, including many miles on the Great Loop.  Use it only with a situational-awareness of your locale and the apps limitations.

Marine Weather” by Bluefin is pretty good for an easy-to-use app that presents the familiar, comfortable NOAA Marine Zone forecasts in plain English text.

Raindar” by Gerrit Van Doorn is the best weather RADAR solution I’ve found for realtime display of nasty approaching Weather.  It does a good job of projecting storm cell future tracks and of highlighting cells that contain rotating upper air components.

Anchor Watch Pro” and “Drag Queen” are anchor-drag monitors/alarms.  “Anchor Watch Pro” features a graphic presentation of the boats position relative to the anchor, but in order to get the audible alarm, I did have to invest $6 bucks in it.  Jeff Siegel says he has a plan for “Drag King,” which will have the graphics position presentation when it arrives, but he has plenty on his plate right now.

Currents” by Yoyana is A SUPERB SOLUTION for cruisers.  It gives an easy to use, visually excellent, display of tidal currents.  It is by far the most useful app I have on an Android platform.  I wish this little Jewel was available on iOS!

There are several Tide and Current prediction apps around; several.  I am not a big fan of any of them because they almost all require the user to know the names of tide stations.  That might work in ones home area, but it’s generally useless when away from home area local knowledge, as when on the great loop or other long range cruise.  I finally settled on “Tides and Currents” by FlyToMap.  It requires the user to know the names of tide stations, but at least it uses the smart phone’s GPS to sort by distance to nearby stations.

Sanctuary subscribes to BoatUS on-water towing insurance, and I set up the “BoatUS” app. as soon as I became aware of it.  We used it once a year ago, at 07h00, on an early November morning.  We’d had a sudden engine shutdown, could not re-light, and could not raise BoatUS by VHF.  The app worked flawlessly.  I was most impressed…  And relieved, too!

SeaTow has a similar app.

Cardinal Marks” is a rather simplistic app, but could be useful for US boaters in Canada, where the ILS Cardinal buoyage system is used.

iKitesurf” is an app that graphically presents surface wind speeds and directions.  The app is free, simple and reasonably functional.

PredictWind” is an app that graphically presents and forecasts surface wind speeds and direction.  The free version is severely restricted.  It has tiered subscription services that provide more function, but seem to me to be quite pricey.  For me, it does not offer a good value equation at the price-point.

Marine Compass”  is a…    hand-bearing Compass for your smart phone.

Finally, there are several good knot tying apps and a couple of “toy” apps worth mentioning.  When passing those huge tows on the Inland Rivers, perhaps wondering what they might be carrying, an app that will scare the daylights out of you is “Cargo Decoder,” by Software Strategies.  Enter the four-digit DOT Chemical Code and the app translates it into semi-understandable chemical names.  They are all hazardous materials (HAZMAT); you know, stuff like nitrates, biologicals, explosives, toxins, etc.  Of course, just the act of having this app on your smart phone proves you’re a terrorist, but hey…

FlagBag” by Digiburo is a fun app if you have kids (or an Admiral) onboard.

Flags Of The World” is also fun for kids and Admirals, particularly in large seaports with a presence of Foreign Flagged vessels.

Marine Wind Calculator” is a wind-speed scale converter; it converts back-and-forth between Beaufort, knots, mph, kph, and meters-per-second.  It only converts; there is no functionality to determine or measure wind speed.


SEAiq USA navigation app on an iPad (iOS7) platform

I was recently referred by a friend to an iPad marine navigation app called SEAiq USA.  This app is in the same family of apps as Garmin BlueChart Mobile, iNavX, Nobeltech TimeZero, EarthNC and several others. I was attracted to SEAiq USA by its very modest price point and seemingly rich functionality.  I have not been disappointed!

The SEAiq products (SEAiq USA, SEAiq International and SEAiq Pilot) have been developed by a live-aboard cruiser who really understands what cruising boat captains need and want to see.  The SEAiq USA app is $9.95 on iTunes (September, 2013).  It uses free NOAA and US Army Corps of Engineers Raster and Vector Charts.  That alone is very desirable, because many of the competing nav apps have free apps but charge significant fees for proprietary chart paks.  That causes two problems.  I hate the ongoing, recurring cost for charts, and I don’t like the idea that the charts are modified for any reason.  With SEAiq, there are no separate fees for charts, and no periodic advertising nag-messages to update your chart paks and drive the manufacturer’s revenue stream.

SEAiq has two operational modes.  One, it can use the GPS receiver that’s built-in to an iPad (an iPad with wireless phone capability and a “real” GPS receiver).  Two, it can use data streamed to it via a wi-fi connection.  I have tested with both modes.  Using the internal iPad GPS, I have basic position, course and speed info.  Using fully streamed wi-fi data, I have pretty much all of the NMEA0183 and N2K data that my instruments are able to send.  So, the iPad internal GPS mode is somewhat more limited than with streamed external data.

Sanctuary is fit with a DMK 11A multiplexor that receives NMEA0183, N2K and Raymarine Seatalk navigation data from onboard navigation instruments and re-transmits that data over wi-fi.  Via the wi-fi link, SEAiq gets lat/lon position data, SOG, COG, Distance-to-Waypoint, Bearing-to-Waypoint, Water Depth, and Water Temp from our made-for-purpose nav instruments, and the full set of AIS vessel data from our AIS receiver.  SEAiq supports many more NMEA data types for which I do not have sensors aboard (wind, etc).

SEAiq has full ActiveCaptain data functionality. It supports (via “import” and “export” using iTunes file transfer) tracks and routes in both .gpx and .kml formats.  In US Coastal and Inland waters, it automatically receives large scale synoptic-level weather charts from NOAA/NWS in .grib format.  On offshore passages, it can do manual requests for synoptic-level .grib files via email, to, using a sat phone or a computer-based email program with Paxtor modem and SSB radio capability.  Data types automatically received from NOAA/NWS are wind and air pressure.  Presumably, additional data types would be available on manual requests, but I have not played with that.  SEAiq does not, at present, support weather RADAR data feeds.  Since there are several apps that do that (Intellicast, Wunderground, Accuweather, Weatherbug), I do not feel that’s much of a limitation.

Aboard Sanctuary, we have always preferred to pilot the boat from the flybridge, and that’s where we have placed our made-for-purpose marine navigation equipment.  We have Garmin and Raymarine chart plotters, depth sounder, AIS receiver, VHF w/DSC, autopilot, etc.  This is a mix of legacy NMEA0183 and new N2K equipment.  In the past, we did not invest  in duplicating all that equipment at our inside salon helm station because we rarely – half dozen times in 10 years – pilot from inside.  SEAiq on the iPad, with nav data streaming from made-for-purpose nav instruments via the DMK 11A multiplexor, gives us a very complete, portable, nav solution at the salon helm station.  We anticipate this capability could be helpful in falls seasons with early cold weather, on cloudy, drizzly, 45ºF days on the Chesapeake Bay, or on night crossings of the Gulf-of-Mexico.

So in many ways, SEAiq is more feature rich than its competitors, and at a much better price-point.  Buy it once, updates forever.

Following is a screen shot of SEAiq USA on my iPad.  This screen shot show a section of the Patapsco River approach to Baltimore Harbor, off Sparrows Point.  The teardrops are ActiveCaptain markers.  The data panel of the right shows the data being received from my nav instruments.  The AIS data shows a USCG Cutter (Sledge) highlighted as a nearby AIS target.

iPad screen shot of SEAiq USA showing NMEA0183 and AIS instrument data fields

iPad screen shot of SEAiq USA showing NMEA0183 and AIS instrument data fields

The SEAiq developer is a cruising live-aboard, and he is very responsive and helpful.  I strongly recommend this app for any boater with an iPad.