Building the Fridge

We knew that we were going to have refrigeration on the boat, that wasn't an option for us. Serena doesn't feel comfortable with certain foods not being cooled, no matter how many people tell her its okay, and I like cold beer, cold apples, cold pop, and a lot of other things, important things, things no man should have to do without, essentials of life, like ice cubes for rum and cokes.

So last Aug, we came across a deal for a Nova Cool RT6 icebox conversion kit with the small .6 cu.ft. freezer box, just like Ralf Kramden and the ol' ice box. There are a lot of different systems out there, and I chose this one because it was the one that appealed to me the most. Light on power, very capable in a small box situation, no thru hulls, rather inexpensive, and I could build the box the way I wanted, with 6" of insulation.

Sometime between when I had those grand ideas, and now, reality stepped in and smacked me in the side of the head. A Bayfield 29 is not some cavernous 6000 sq ft log chalet in the mountains, its a little boat, with little spaces. Does anyone have any idea how much space 6" of insulation actually takes up. Well I do, I figured it out, and its tremendous, its huge, its also not going to happen in a 29' boat.

So I have had to make compromises between the size of the fridge, the amount of insulation, and the amount of power needed to keep it going for a day in the tropics.

I have some code board left over from building the house. It is R9 and 1 1\2" thick. So, 3" is R18, and 4.5" is R27. Very respectable values, and the board is foil backed, so it helps seal up the insulation a little better. It works good on the house, we can almost heat this place with a candle, and cool it with the fridge door open.

So, the compromise. I ended up with a 3 cu.ft. box. Part of that is freezer, about .6 cu.ft., and the remainder is is fridge. Its not much bigger than a large cooler, so that helps make it easier to cool, ultimately decreasing the power requirement. The insulation is 3 layers thick of code board, or 4.5" on the back, the right side beside the stove, the top, and the bottom. The front and the side will be 2 layers at 3". Its amazing the difference in the volume just removing a single layer of insulation from 2 sides.

 So then I started building the box. There is a step up on the back side where the freezer compartment goes, in order to eliminate the area underneath that would be difficult to access, but also to maintain a good amount of insulation without the hull getting in the way. I used 1/4" marine grade plywood for the box. Normally I would wire it together before putting the internal fillets in as in stitch and glue, but the box isn't very big, so I just used masking tape.

The box is 19 1/2" wide, 17 1/2" front to back, and 18" deep. The step up reduces the depth of the box at the back to 14", and leaves a little space under the freezer compartment to get a hand under there to wipe up spills or what ever. Not huge, but it will have two small baskets in the top, one 4" deep, and the other 7" deep, for smaller items, and will effectively double the square footage.

Here is a picture of the epoxy fillets. I made a piping bag out of a plastic bag, and faired the corners with a tongue depressor. Tomorrow I'll tape the corners with 2" fiberglass tape. After I get back from painting the second coat of bottom paint on the boat.

So according to my calculations, with the help of Nigel Calder's book, I figured conservatively that the fridge and freezer will use about 32 Amp hrs per day. We can get that out of our solar panels alone. I expect that the number will be much lower though on average, down closer to about 22 Amp hrs, but time will tell.

My biggest concern is that because the the box is so small, that I may have a hard time keeping the stuff in the freezer frozen without freezing everything in the fridge. According to the documentation for the Nova Kool, I could use this as all freezer too. I may end up putting a divider between the fridge and freezer part just slow the transfer of cold air. Have to wait and see.

Also got my first coat of Cetol Marine gloss on the ladder steps. Man that stuff stinks. I was going to use it down below in the boat, but it would kill me, so I think I'll find a water based low odor varathane instead.

And the saga continues...

Rob