Re: Continuous duty, non-thermally compensated alternator: options?
How big is your battery bank? What loads do you have on the boat? Refrigeration? Incandescent lighting? Fans? How long do you want to be away from shore power?
I was in your position a few years ago on my Bombay Clipper 31. I spent a few weeks a year on it with the original 35 amp alternator. No fridge. I swapped all the lights out for LEDs which greatly extended time between charging.
Eventually I added a fridge, installed 2 golf cart batteries, a Victron battery monitor and a Kyocera 145 watt solar panel. Unless I had 3 straight days of rain, I never had to run the engine again for charging. Boat was electrically self sufficient. Ice cold drinks year round from the sun was a great investment.
Not know your sailing area, I think switching to LEDs, efficient fans, etc., is a better use of funds than spending much on a higher end alternator. I ran an 80 amp Hitachi on my little 2QM for awhile and it was too much load if the batteries were down. In other words, I'd suggest reducing your loads (if possible) before increasing the charging capacity.