Hi Dean. Ya, I'll need the heaters when I come up to play "you sunk my
battleship" with you.
Lake Superior IS cold. I grew up on Lake Ontario and I remember when we'd
get ice flows coming off the lake. It would pile up 20 feet or better on the
beach. Fun for kids playing in the ice caves and stuff. Scary when I think how
stupid we were, but hey, it was lots of fun.
For heaters....well, that's a tough one. I'm very miserly with my
electrical usage. I've been leaning toward a chemical solution rather than
some kind of electrical resistance heater. My thought was that it'll be
necessary to change out the air scrubber chemicals anyway, and a canister type
thing with the scrubber chemical and another with a heater canister should be
able to be incorporated into a "quick change" chamber with a small 12 volt
fan. The outlet would blow clean, dry, warm air over the windows to ventilate
the sub. The device will need a small condensate reservoir or trap, which
would need emptying after a dive, and of course replacement of the scrubber
canister and heater canister.
The trick is to make the canisters reuseable so you could carry a couple
of sets, and just change the raw chemicals in the spares each day. Self
heating chemicals are easy to get, and a finned two chamber canister, where
the air flows over the fins, should be fairly easy to make. Pack the stuff in
there, shake it up, put it into the fan unit, and warm air comes out.
My buddy has a little can thing he puts in his pocket when we ride on
cold nights. He puts his hand in there and it warms right up. Good for about
three hours. Seems like a larger unit with a fan could do the same thing.
Haven't got that far yet, but I'm thinkin.......
Frank D.