My primary need for self generated power is for AC, which even here in Maine is useful to have to decrease dampness.
No need for air cond , what you need is a dehumidifier , if the boats natural venting can not be brought up to spec.
This will operate fine with a Honda , as required.
About 1/6 the cost of a diesel noisemaker , plus install, plus purchasing and installing an air cond setup.
With the Maine water temps , I would assume a nice wood stove would solve the problem , rather than air cond .
Living in an air cond boat means it must be closed up, canned air in Maine? UGGGH!