I am going for them on my new 40 ft cat, using the 39 hp engines. You can go up to 6 kVA with an extra control box
, weighing around 15 kgs.
You need to take care that only one engine
at a time can supply AC power to the mains ring on the boat.
My decision is to also split my battery
banks in 2, with 2 chargers, to get the shortest possible charge times.
A simple interlock relay will fix the problem.
The advantage is that these don't load up the bearings at the front of the engine
like a high output DC alternator
I will just keep the standard alternators and let them charge the start batteries only, and make a manual DC crosslink between the engines if one of the start batteries dies on me.