The first passage of my current cruise began 11 years ago and was from Hawaii to the Republic of the Marshall Islands. After eight years in the Sandwich Islands I was unaccustomed to the weather patterns common to the latitudes of Micronesia. I soon learned that the nights were difficult to sleep through due to the numerous rainshowers and squalls that would unexpectedly appear and cause a mad rush to close the hatch over the vee berth. Settling off to sleep, it would soon become too hot and I would awaken and open the hatch for some relief. This cycle would repeat itself throughout the night. In frustration I vowed to find a solution.
A dorade box was the inspiration for my solution. Using acrylic yacht fabric, I fabricated a windscoop-style cover, shaped as a dorade, that fits over the opened hatch (which provides back support to the windscoop). The front and inner flaps direct the rain-laden wind down and then up, causing the rain to fall on the deck and only the fresh air to enter the hatch.Some design hints
To determine the correct dimensions I used string and a piece of 1/2-inch PVC pipe (length equal to the width of the hatch). A cat’s cradle of string tied in place around and over the opened hatch will easily give the distances between the critical points. For the best shape under tension, a peaked roof is desirable. Make sure that the front and inner flaps, when viewed from the horizontal, should overlap a few inches to give the best protection from rain, which can blow horizontally during a squall.Construction
Normal canvas construction techniques are used throughout. Only two seams in the roof are necessary, along the sides of the triangular front piece. To give maximum air flow when there’s no chance of a squall, the front and inner flaps can be folded away. Velcro works nicely for this purpose on the flap sides and to hold the front flap up against the top. The windscoop bottom fits around and attaches to the base of the hatch with common-sense fasteners, one at each corner. A piece of metal rod sewn into a sleeve at the back holds the scoop on the deck, preventing rain from splashing through the opening at the back of the hatch where a gap is formed by the hinges. The sides of the scoop at the front are attached to the toerail. In my case, grommets slip over hooks attached to the inside of the rail, though common-sense fasteners would work here as well. The PVC pipe fits into a sleeve at the top front of the scoop. A line through this pipe joins another line coming from the top peak of the scoop. The three lines join in a knot with a single line leading to the forestay to give forward and upper support. A bit of experimenting with these lines will result in a taut shape to the windscoop.