Navigation Via PC Tablet Computer

Navigation Via PC or Tablet Computer

by Jim Healy

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. 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.

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.

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)

By Jim Healy from his Blog Travels of the Monk 36 Trawler, Sanctuary

Disclaimer: Curtis Stokes and Associates does not necessarily agree or promote the content by the above author. This content is to be used only with the reader’s discretion.