I suppose it is theoretically possible. I have heard of people running the ARM Debian build on the Kindle 3, and some people have been working on getting X applications working.
From there, it would be a matter of cross-compiling OpenCPN to ARM (assuming the program is suitably portable).
But as for how practical it is, or the likelyhood you would get it to work, I would say you might as well forget about it.
If you want to follow along with Debian on the Kindle anyway, check out this topic:
http://www.mobileread.com/forums/showthread.php?t=99021
