Refrigeration Conservation... (smile)...
Well, as this is the cruising forum, I felt it might be beneficial to discuss refrigeration techniques that have worked for us to keep your 12v costs at a minimum. I am not the final expert on this (or anything in life, for that matter), so I urge anyone with other ideas to feel free and chip in.
Refrigeration. It is one of those things that I have had old salts tell me you do not need, but I will be darned if I will do without. There would be a mutiny of kids, wife, and dogs (not sure who would lead it either!!). But, refrigeration has the distinction of being about the biggest electrical hog on a boat on the hook. Many of the modern coastal production cruisers use Adler-Barbor refrigeration, as I do. Short of sticking an ice-pick through it (no laughs... it COULD happen to you!!), it has served us well on our many trips. The general budget for a AB system is about 50-60 ah/day. With that in mind, even large 12v systems will begin to get taxed before long. Thus, here are some key ways you can do your own Refrigeration Conservation:
1) Stick your head inside the box and look around for holes. Sound silly? I bet if you own a production boat (or almost any boat) you will see the refrigeration lines come right into the box and are not sealed!! It is like leaving the door cracked or lid up! Depending on the size, you can use MG caulk or even the can of Foam Stuff to seal it in. If you use the latter, let it dry completely before you cut it to shape. Acetone cleans it up when wet. A putty knife cuts to shape when dry.
2) Plug the drain (foot drain) with a cork or similair object. It might not save you much, but I see no reason to cool the water under the boat. Keep the T-Hull closed too - though I am sure this is a practice most people do anyways.
3) Use thick plastic sheets to cover the inside of the front door. Remember when you would walk through the old grocery stores and you had to reach through hanging plastic to get something that was refrigerated? Make a similair system on your boat. Thick plastic, cut in strips, screw it just to the inside of the door at the top.
4) Resist opening the front door. Even with the plastic strips, when you open the front door the cold air comes straight out. On a passage, I drop a little screw through the "lock hole" so it cannot be opened by those who forget (ie, the kids). On long runs, pack the things you will need most on top through the top-load.
5) Double insulate. Styrofoam, for all of its negatives on the environment, is one of the best insulators and is dirt cheap. I would not do this unless the original box was not well insulated (as this takes up some room in the box), but it is a consideration.
6) Use a "heat blanket" on top. You know the aluminum emergency heat blankets you can buy at about any backpacking store? They keep in cold too. They are cheap. Put one aross the top of your box (on the inside) where you have to push it to the side to get the item(s) you need.
7) Keep your fridge stocked. The more stuff in there, the better. A super-stocked fridge (once it has gotten all of the items cold) will maintain its own temperature better. The cold items act as their own cold plate. You also seriously minimize the air inside, which is most apt to dissapear when you open the door.
I hope some of these tricks help some of you as you gear up to punch off - whether around the bay or around the horn. They have worked for us.
Great sailing and fair winds -