WAFIs have used them to provide wireless routing (pick up the marina Wifi and share it, use 3g if no wifi that sort of thing) plus provide some home moniotring - battery state, bilge level, bilge pump use, GPS location etc.
In theory you can run Open Charting Software on it. But then you need a screen which will cost you as much as a tablet but not have the portability to bring it home and play etc.
I'd suggest the Pi is useful for something headless (i.e. it sends data to another PC) or something that might output to a 16 x 2 LCD panel which can be done from a Pi for about £10.
But I agree (OMG) with Poly - find the problem then the solution. If the solution is a Pi thats great. But some of the WAFI guys say the Pi is overkill for some solutions and at 800mA of 5V power is eating 20 x what a Arduino could draw for the same task.
Just to note the power draw is up to 1A at 5V - so I think the power supply mentioned in mW above might have been meant to be mA. If I was putting this on a boat I'd pick one of 2 things:
- A 4 port USB socket something like this:
New DC 12V 24V 40V to 5V 4 USB Step Down USB Step-down Power Supply Module | eBay
to give me some extra USB charging ports for phones etc. or even:
12V Dual Car Cigarette Lighter Socket Charger Power Adapter USB Splitter 1A 2.1A | eBay
Both with a USB standard to USB mini onto the Pi power socket.
OR if I knew i had a permenant fix I'd just use something like this:
2014 New Waterproof DC Converter 12V Step Down to 5V 3A 15W Power Supply Module | eBay
(or a non encased version within the PI case) - connected directly to the PI GPIO
You might need to watch what happens with all of these when the engine is starting - the available voltage may drop to < 9V causing the PI voltage to drop out momentarily. There are means and ways round this using capacitors etc - if it was an issue the Pi community would soon find you a suitable circuit!