Roger,

Why don't you look into an AC and engine run compressor with holding plates.
I put in a Technautics system a few years ago and I love it. I only put in
the 12 volts system but they have other configurations. Check it out:
http://www.technauticsinc.com

If you are in Rockland look me up and I can show you my system.

Ansley Sawyer
SV Pacem

Waeco & others make coolers with proper refrigeration compressors - You
could use this at the dock on AC and if you include some freezer packs or
even just frozen water bottles, you will get through a day without buying
ice.

If you have a small 110V generator, you could run the refrig unit every now
and then and even make some hot water on the go.