...Small sailboat? So, probably a 12 volt battery..
746 watts is 62 amps at 12 volts-far too much for your battery...

Maybe once upon a time?

But these days....

The folks I've talked to with towed generators love them and claim
they get about an amp per knot and it takes about half a knot off
their boat speed... I suspect they are being generous. Nevertheless,
if you need 60 amps all the time you really need a genset. Even with
a 12 volt fridge and autopilot 5-6 amps should pretty much keep up
with demand.

-- Tom.