I would not run any audio equipment direct from a boat generator. You need a good battery backup UPS that also restores a clean sign wave. The AC out of generators is ugly and needs a lot of treatment before connecting to modern electronics and that includes your computers.
You really should call in professional help and look at the wave and voltage stability of the generator, and see what someone knowledgeable recommends.
Switching power supplies of subs are especially vulnerable.
There are generators on the market that can do the job, no doubt about it.
My previous job, we ran mobile analytical labs, in trailers, off of generators (the one in my lab was diesel-powered). We ran IR, FTIR, and other quantum-physics-based analytical techniques from those generators. If those very sensitive instruments ran fine, then stereo equipment will run fine.
We did have a UPS system too, but it was nothing fancy, and I highly doubt that it improved upon the power from the generator. However, we are talking about a $15K generator.
