Two years ago my husband bought what is called a "Truckers Tarp". It is very heavy and has a line of d-rings around the perimeter of it. The tarp fits over the boom and goes around the mast (we support the aft end of the boom with a 2x4 between it and the cockpit sole). We tie it off at the toe rail and we can enclose the whole cockpit securely which allows us to store our bikes in there too and still have easy access during the winter when we need it. It cost a little over $200 but our marina is impressed with how well it has performed. They hate the blue tarps because they fail frequently. It's not a custom cover but at $3k for one of those I'll take our semi custom happily!
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