I love diesel gensets but they are old technology. Why not consider an EFOY? Basically a fuel cell. Much cheaper, simpler and so quiet.
https://www.efoy-pro.com
Let's see, why not:
A) Both methanol and hydrogen are in the same class as gasoline for explosion risk, so the unit and the fuel would have to go in a separate compartment, like propane.
B) On equal energy content, both fuels are considerably more expensive than diesel.
C) EFOY quotes 0.9L of methanol per kWh. That's 0.24 US gallons. An NL 5kW generator uses about half a gallon of diesel per hour at full capacity or 0.1 gallon per kWh. And, surprisingly, at half load the consumption is only a little more than half of full load.
D) Therefore the methanol storage will take at a minimum of 2.4 times the volume of the diesel required to produce the same power, and, unlike diesel in a tank, is in containers that occupy more space than their contents.
E) Diesel has about 2.3 times the energy content of methanol on a volume basis. (129,500 btu/gallon vs 56,800) Since the EFOY unit uses 2.4 times as much fuel, it is actually less efficient at using the contained energy than a diesel generator, so while "fuel cell" sounds green, it's not.
F) EFOY is a single source vendor for the fuel cartridges.
G) Rolling and pitching (inclination angle) are an issue.
H) We all already have diesel aboard.
Jim