Tanks and Sleds

One of the things that has bothered me about the boat is the arrangement of fresh water tanks. The port side had 4 x 10 gallon interconnected tanks under the floorboards in the nav station/dinette area. There are two more 10 gallon tanks in the bilge under the master berth. There are rectangular polyethylene tanks–a poor fit for the deep V shape of the hulls. The numerous interconnected fittings leak into inaccessible space under the tanks. It’s a lot of wasted space. It’s way too much water in the bilge. Wharrams should have dry bilges, and the idea of collecting fresh water in the bilge under the tanks just doesn’t fly. So out go the leaky old poly tanks.

After a lot of thought, I settled on building an integral tank that will use the interior of the hull as the bottom and sides and the cabin sole as the top. This maximizes the use of space; a 50 gallon tank will fit in space previously occupied by two 10 gallon tanks. Large watertight inspection plates allow access to all parts of the tank–no more blind spaces where leaking water can accumulate.

The Gougeon Brothers have detailed instructions on how to build an integral tank. I have followed these instructions closely. Tank walls have a total of 50 grams of cloth layup on the bottom and sides, and 25 grams on the top. The glass is sealed with two coats of marine epoxy. This is topped with two coats of NSF certified potable water epoxy. This last part is important. The Gougeon Brothers do not certify their epoxy for potable water use. The final coats are a product called LiquaTile 1172 by Wolverine Coatings. This product is certified for use in potable water tanks as small as fifty gallons. This should guarantee safe, good tasking drinking water.

I put A LOT of work into making sure the tank is completely waterproof. In particular, I wanted to be certain there is no possibility of water seeping into the wood core under the glass on the tank interior. I am confident that the interior of the tank is every bit as waterproof as the exterior of the hull below the waterline.

While the tanks are in progress, I got to work on new sleds for the outboard engines. The old sleds were made of galvanized angle stock and plywood. While they were very sturdy, the steel was rusting badly, and the design resulted in a lot of water intrusion into the powerheads.

I’ve been admiring the sleds on the Tikis, so I purchased plans for them from the Wharram office. It’s basic stitch-and-glue construction, with thick interior fillets and heavy biaxial cloth on the interior seams and over the entire exterior. G10 sheets reinforce the transom, pivot pin holes, and block attachment points.

I’m very happy with the results. These new sleds weigh about as much as the old ones but are visually much sleeker and provide better function. They have a lot of extra reinforcement: biaxial glass, G10 backers, thickened epoxy annuli. I expect them to last the lifetime of the boat.

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