It seems like a bunch of us have (semi) independently arrived at the idea that a Raspberry Pi equipped with OpenCPN would make for a good boat computer. Some of us have gone as far as to install OpenPlotter on a Pi.
Has anyone made more progress than that? Do you have any ideas/suggestions/recommendations?
I looked at this a lot. I set up OpenCPN and a few other instrument programs in both windows and Linux. But the thing that kept holding me back was the hardware. Specifically a waterproof daylight readable screen with low power draw. The screens I found were really expensive and just did not make sense. Also there is something to be said for a unit that is simple, easy to use and does not require a bunch of components to function.
I have used Navionics on my tablet, which is a great program, but again, using that tablet in bright sunshine is brutal. I think part of the issue here unique to a sailboat. If you are in a powerboat with and inside (dry) bridge, the requirements are likely different.
After going round and round on this, I recently bought a Garmin 9" chartplotter. I will still have OpenCPN onboard on my laptop, but it will not be my primary nav equipment.
About 4 years ago I went through this very same process. PI at the time was very low in computing power and OpenCPN ran but was a resource hog. I too had problems finding an economic solution to the screen. I ended up sponsoring a crowd funded Raspberry PI specific HDMI screen that took forever to develop and arrive. When it did arrive it wasn’t touch capable (another issue for in cockpit use) requiring a mouse or KB to navigate the screen. I used this system mounted behind my dodger for a season with AIS via a software based radio working fairly well at times. WIFI worked and I had that going to an old tablet (apple) using iNavX. The other instruments on the boat are so old and based on individual proprietary data links that I passed in attempting to link them. Ultimately I installed OpenCPN on a laptop down in Nav station for “over view” and plotting purposes and use a combination of a small handheld GPS and a Navionics on iPhone for cockpit reference. This works for daytime operations but I wouldn’t rely on it for night time sailing.
Ultimately I will end up with a Vesper AIS system including WIFI/ GPS and will install a new depth/speed/temp sensor. All of that data will be available to any WIFI device onboard which may make a low power PI based device very useful again.
At the risk of taking this thread sideways, I have a question to the group on knotmeters. I need to replace my old Simrad knotmeter. (It has gotten to the point were the screen is difficult to read). I am looking at ones that were the transducer does not have a paddle wheel. This sounds interesting as keeping the paddle wheel clean can be a pain, but I also hear that these units can fail due to slime on the hull. Does anyone have thoughts on this? thanks
I looked at the Airmar Ultrasonic transducers, I wanted to get one but couldn’t get one in an instrument package. I do have an extra brand new Airmar triducer (speed, depth, temperature) that I bought prior to replacing the entire system that is available cheap, you are welcome to try it.
I am really interested in taking you up on that. Lets connect after the holidays.
I have one of these: https://www.vyacht.net/specification.html
I haven’t had a chance to place with it much. Seems to do the trick.
The VYacht solution seems low-cost and easy to implement, but I think there is a future in things like the Raspberry Pi (of which they’ve apparently made more than 25 million). Some people have already made HATs for marine applications, and the Pis are capable of doing all kinds of neat stuff.
I use the Vesper XB 6000 GPS/AIS/Wifi feeding by wifi into an android tablet running Sailgrib Weather Routing with Navionics charts. Simple and inexpensive.
Here is an interesting Excel file for editing/creating polar files.
https://www.sailgrib.com/wp-content/uploads/2019/03/Create-SailGrib-Polar.xls
Wraith, that is a pretty cool xls. For those of us who do not have polars for our boats, where do you get the data? Have you ever played with OpenCPN to generate polar data?
If you are fortunate, a Class Association will have polars, or the designer, packages such as Expedition or Sailgrib have many common designs, and then there is also ORC’s Sailor Services. I think you need to be aware that if you build your polars through Open CPN I believe that you will be mapping out your “as sailed” performance as opposed to target performance.
I contacted my designer and he said they did not build them for my boat. Good tip on the ORC. On the as sailed, I could just get you to helm my boat and make them for me, then I could sail to that target 
I used the Seascape 27 file and edited it with my ORC data, however ORC only models between 6 and 20 knots so there was a bit of guess work extrapolating beyond that.