The newer Norcolds--which most C Dories now have use the Danfoss compressor, not the old Japanese swing motor compressor and are as about effecient as most of the other refigerators available. But look at Tundra and Nova Cool--both are highly recommended.
We also find that our Norcold in the CD 25 runs about 50 % of the time--no matter what the ambient temp...We don't depend on the refigerator for long trips, but use two large ice chests. One ice chest we only get into once a day, the other we keep soft drinks etc in and put food for dinner in it from the less opened box. We keep wet towels over the ice boxes and that significantly helps keep the ice.
In the past we have found that a Norcold pretty much drains a group 31 battery in 24 hours. (110 amp hours--x average of 2.5 amps-x 24 hours is close to 55 amp hours or 50% discharge--and that is as much as you should take the battery down).
These refigs don't have much room, in comparison to the larger ref we had in rV's or the serious holding plate systems (6 to 10 feet each freezer or refigerator) I am not aware of any good holding plate or top loading system, other than what we or several others have in our Tom Cats. Although there are some advantages of a 12 volt holding plate system, it is no where as effecient as the 110 V large compressor/large plates or engine driven compressor systems--which will hold a freezer at 10 degrees or less for 24 hours on an hour of run time.
We have the Norcold top loading chest type refigerator/freezer in the Tom Cat and I like that much better than the CD front loading refigerator. It will be either a refig or freezer--which the front loading will not, and it will contain considerably more food. We put frozen food in the top loader and use the entrees daily--allowing them to thaw in the ice chests.
We didn't have a refig in the 22, and I didn't consider putting one in. I ordered the tC 255 without a refig, planing to put in the top loader. The 25 came with the refig--and we are keeping it--great for dock side and the small amounts of food when I visit Calif--but for long trips, we want more room--but for the loop anything will do--you can get to stores and ice almost every day--sometimes a bit of a walk, but often you will be given a ride.
Our rig in the Tom Cat 255:
We put tackle boxes in back of and around the top loader--contain spare parts and fishing tackle--and allows effecient use of space for storage. We have 300 lb capacity ball bearing rails that the freezer rolls out on and use a single 1/4" bolt to pin the roller mechanism when we are at sea and the cabinet door is shut.
