Re: Mount above-deck gas tank below-deck?
You don't need to make a cover. Just paint the tank (leaving the top surfaces red). The portion that crosses the shear strip can be painted "Pepsi Blue" (I assume that's the color of yours as it was the most common on Cal's) and the lower portion white to blend in with the hull. Just use a plastic primer and then a common semi-gloss latex paint. It won't last forever but it will several years at a time and certainly until you get your inboard replaced. And, the tank can later be used for your dinghy, eh?
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."