The BSB format (NOAA raster charts) is much easier and additionally a
library exists for it already (libbsb.sourceforge.net)

Yes, this is probably what I'll have to start with. Ones I have everything
up and running I can switch to the "S-57" charts. (If I can find some
documentation that is usable

No matter what you do you're going to need C/C++ experience and a lot of
patience to deal with the marine industry roadblocks. It would be nice
to have a viable linux navigation package. And, have a look at my
project (pynavigate.googlecode.com), its a working cross-platform GPS
display written in python.

I am a computer programmer by trade, so the C/C++ part is no problem.
My idea was to make it run on Linux and Windows, but haven't decided yet.

I will certainly have a look at your project, but haven't done much in python
so there is a small learning curve for me.

My end goal with this project would be a very complete "marine system"
Some of the things I would like to do with this system is:

- Basic navigation
- Control the autopilot drive unit directly
- Connect a "3d-piezogyro" (?) so that the autopilot can follow and correct
the waves - and ignore them when it should
- Have an internet browser so you can check weather/harbour info
- Connect a radar
- Feed all the info to a secondary display below deck so if someone wants
to know where we are right now or the speed or the wind conditions ...
- etc

Right now I am using a standard ITX motherboard (12W) and a daylight readable
touchscreen display (12W). If I get the system usable I will have to look for
some less power hungry hardware.

Josce