Propane Installation
I converted from Kerosine to propane on my 37C. The tank does have to be enclosed and the bottom of the box has to be vented outside the hull. This means the tank has to be above the waterline (even when healing). In order to satisfy my insurance company (Boat/US), I coordinated my installation with my underwriter. He was VERY knowledgable and sent me copies of the ABYC? Specs. I built numerous boxes out of cardboard and duct tape to experiment with different locations and tank shapes/sizes. When that was decided, I had the box built out of 3/8 inch plexiglass. My propane shop referred to my box as the "propane aquarium". One other comment - The installation should include a pressure gage (per specs). By the time you include the pressure gage, regulator and fittings the manifold can become one of the determining factors in box size and shape. On my 37C, it was very difficult to find space big enough and still be above the water line. I ended up installing it under the aft cockpit seat on the port side. The vent goes out the transom on the boat centerline so it stays above the water line on either tack. I used a lot bigger tank than what is really needed (it is a horizontally mounted, commercial, life time guananteed, steel tank - 7 gallons, I think), but since we only weekend sail, the space used for the tank was not that valuable. Good luck. When it's done you'll really be glad you did it.