Commercial chartplotters are expensive, really expensive. Considering that you can get a 10″ tablet device with better touch screen, faster processor, better responsiveness and much smaller size with a 1/4 of the chart plotter cost, it seems like chartplotters are totally overpriced. I cartel, someone might suspect. That is what I also thought, but then I spent some time trying to design and build a chartplotter that could be sold commercially (and I am not the only one). I learned some things on the way, please keep reading to find out more.
The chartplotter, in a very simplified terms, contains the following
- display (with touchscreen)
- computer and other electronics (wifi, gps, NMEA gateway etc.) and voltage converters and regulators
- (protective) enclosure, buttons and connectors
The goal would be to build a chartplotter that is clearly cheaper than the current ones and possibly also better in some aspects. Let’s see what we can do.
Let’s start with the display. It should have a brightness of at least 1 000 – 1 500 nits (cd/m2). Standard computer displays are somewhere around 250-350 nits. Best tablets are at 600 nits. In addition to brightness, the display should have an anti-reflective layer (not some plastic sheet attached to the screen, but an optically bonded layer). Further, the display needs to withstand direct sunlight for extended periods in hot temperatures. Bright display (generating heat) with direct sunlight exposure is not a good match, if you think about reliability. The display, with the enclosure, should also withstand changing temperatures and humid and salty environment and water pouring directly over it (more about the in the enclosure section).
As you may have seen, I did an extensive study on the available sunlight readable displays and monitors. The cost for these displays is much higher than what you see on normal monitors. Also, I did not even test the reliability.
Touchscreen bonded on top of the display lowers the brightness and so does the anti-reflective coating. However, the benefit of these will in most cases overweight the the downsides, so they should be added. Also, there are different anti-reflective layers and the quality of the optical bonding matters, so not all displays with the same construction are equal.
Computer is probably the easiest part of the system. There are small fanless computers available in various forms and sizes. The cost should be kept in minimum, but quite some processing power is needed to enable smooth panning and zooming of the charts.
Enclosure, buttons and connectors
Plotters are used in harsh outdoor environment. Therefore the entire enclosure should be IPX7 or IPX8 rated (see explanation of the IP classes in Wikipedia) and that is what the commercial plotters offer. The connectors need to also match this and they need to have a protective cap over them if they are not in use. All buttons need to also be sealed to this spec.
It is pretty obvious that the system should be build on Linux or Android. That is also what at least some of the commercial chart plotter manufacturers (e.g. Raymarine) are doing. With the low targeted price point, there is no room to pay for the OS. Building your own OS is obviously out of the question.
Building a stable chartplotter SW is going to be a massive task. Fortunately, there are SW like OpenCPN. However, even that would require considerable modifications for it to be used on a commercial chartplotter. I would estimate a couple of developer years, at least.
Chartplotter needs charts. Many charts are owned by companies like Garmin/Navionics or Navico/C-MAP. Using their charts would get you back to their business, and their cost level. Your customers would then need to pay at least 150 euros or dollars for a chart update. Fortunately, there are companies like o-charts that provide official charts with a very moderate cost. While these are official charts, they do miss some of the data that is available on charts from a marine device vendor.
Reliability is a huge issue. Chart plotters are used for at least 10 years, often longer. When you compare that to tablets and add the conditions chartplotters are used into the equation, you start seeing that building a chartplotter is, in terms of reliability and lifetime, much harder than building a tablet.
When you have your prototype ready, you need to build 5 of them and thermo-cycle them to death to see a) how long they last and b) what breaks first. Then you fix the things that broke and do it all over again. After that you make 0-series production and put at least a bunch of those into an accelerated lifetime test.
Because your system is build from 3rd party components, you need to make sure their quality is consistent and also will be in the future. That is not a simple task either.
It actually seems that any marine device which has a display, is expensive because of the display. Also, water tight enclosure and connectors add quite a bit of cost. Then you also have the software development cost that has to be amortized to the relatively small unit sales.
It may be hard to compete in price with the 9″-10″ plotters, but commercial 15″ plotters cost several thousand dollars or euros and 18″ plotters even more. It is however, a massive task to design a chartplotter and offering just a somewhat lower cost large screen plotter is probably not going to attract many buyers. The higher the cost level is, the more people trust the established brands.
An alternative approach would be to change the scope. There is no commercial chartplotter on the market designed for indoor use. Yet, many boaters install the chartplotter inside the cabin where the plotter never sees any water and is also in less bright environment. That would allow the charplotter to use less expensive displays and much cheaper enclosure design. By that way, the plotter footprint could also be reduced making it easier to integrated larger plotter to an existing helm station.