Just another vote for the electric Adler-Barbour air or water-cooled system. I've had one for the past 18 years, including 11 years in the Caribbean. No problems whatsoever; still going strong.
Reasons for this one:
- ultra reliable
- ultra simple
- relatively inexpensive
- allows you to leave boat for reasonable time, if you have adequate house batteries.
The previous post is right: engine-driven compressors are disappearing on cruising boats. They were once very popular, but no longer are.
The A-B Cold Machine may draw a bit more than 5 amps...maybe 6 or so, and it may run more than 11-12 hours per day. Mine runs more like 14-15 in the tropics, but my large top-loading frig/freezer is not very well insulated.
In my experience, you'll want a house battery bank of at least 400AH (e.g., four 6V golf-cart batteries in series/parallel). I moved up to 675AH a few years ago, and that was very beneficial. However, I have an onboard generator, a big battery charger, and a high-output alternator with smart regulator to keep these babies happy.
You could get by on a P365 easily with just about 400AH house batteries supplemented by a couple of good sized solar panels or a smallish and quiet wind generator (like the Ampair 100). Definitely go for a high-output alternator and smart regulator, though. A very good investment.
BTW, I know the P365 very well. Once chartered one in St. Thomas for a couple of months.