Dogskiff
by William R. Watt  ag384@freenet.carleton.ca 
Some of Mr. Watt's work can be found at: http://www.ncf.ca/~ag384/ 

The dogskiff is a light narrow paddling and sailing skiff designed using the math in TF Jones' "Boats To Go". It's construction follows the Bolger/Payson Windsprint with 1 ft. high plywood sides bent around a single centre mold 3 ft wide at the top and 2.5 feet at the bottom. The transom is 2 ft wide at the top and 1.5 ft at the bottom. The sides are 11.75 ft long on the top and 10.75 ft long on the bottom. The bow half angle is 25 degrees. There are no eighths, sixteenths, or thirty-seconds. The measurements are feet, half feet, and quarter feet. Happily this first attempt at boat design came out just right. A 150 lb adult can sit amidships with the bow and transom just above the water.

 The stern was to be luxurious, rounded, flared, and arched to provide a comfortable place to recline in the afternoon sun. And so it is. I've probably spent more time reclining than paddling or sailing. There were to be no seats or thwarts to divide up the interior. The thick gunwales shown with the Windsprint provide stiffness. Two unique features that can be seen are the strips along the bottom and the gunwales to allow deep countersinking of the wood screws in the thin plywood, and the raised stems bored for ropes to avoid the weight and expense of metal hardware. The boat is made from two sheets of the infamous lauan underlay plywood and weighs 50 lb, light enough to be carried upside down on my head using the old horse collar lifejacket for padding. Voids in the plywood were tracked down by running a lamp over the plywood, and filled by boring small holes in the face ply along the voids through which to pump household caulk with a standard household caulking gun. Although the edges of the plywood were sealed with plastic resin glue I have to keep a lookout for hairline cracks in the seams and seal them with drops of epoxy glue spread on with a toothpick. 

The sail is the fabric store nylon canoe and kayak sail in "Boats To Go" cut a bit larger to 42 sq ft and doubled with one side cut up and sewn back together on the bias to reduce stretch. That worked really well. The sprit and mast have loops of line through them so the sprit can be hung on the mast without hardware. The wool reef points which don't show up well in the photo have wooden buttons which pass though loops on the opposite ends.

The sailing rig can easily be removed when not in use, except for the mast step which is screwed into the bottom skids, and the retaining blocks on the gunwales. The partners, like the gunwales, are made from 1x2 spruce strapping. Like the spars and the interior of the hull they have been given two coats of linseed oil. The first coat must be thinned for good penetration of the wood. The linseed oil is renewed annually. The legs on the partners transfer the twisting force from the thin sides down to the chines. The legs fold up when the partners are removed. The small brass hinges loosened under the strain and their pins fell out. The pins have been replaced with bent nails which will not come out. The partners are held down to the gunwales by wooden toggles copied from the ones traditionally found on outhouse doors. I realize now that it would be possible to replace both the legs and the toggles with lines from the partners down to the chines so the rig pulls on the chines instead of pushing on them. I might try that some day. It would be lighter and simpler.

 Lateral resistance is provided by a funny removable collapsible keel screwed to the skids. The sides and bottom of the keel are stitched together loosely with wire. The top is pulled apart when in use and propped open with a stick. The keel is attached to the skids with screws through two hinges and for good measure tied to the transom with a safety line. The top of the keel is fitted to the skids so it sits down between them snug to the hull. When in use the keel fills up with water. A large hole is drilled in the back corner to speed the emptying of the water when the boat is lifted ashore. After a few times out sailing the wire wore through from rubbing on the ground and broke. A thin strip of plywood was cut and drilled to go along the bottom of the keel to protect the wire. After some trial and error the keel is located well back of the where the theory says it should be. As T F Jones points out, light narrow sailing kayaks have a lot more broaching weather helm so need lateral resistance further aft. The keel is too small to meet all the lateral resistance required by the boat. That is also not according to theory. The keel is a prototype made from one of my successful protest signs calling for tax cuts. I might make a bigger one. Because the keel is inconvenient to use I may just install a daggerboard like the one in the Windsprint. I'm not eager to cut a hole in the bottom of the boat to do that. The rig is so well balanced I sail without a rudder, using a paddle to help the boat change tacks.

The dogskiff will carry sailing rig, tent, blankets, and food for a few days. It doesn't paddle well frontwards so I paddle it transom first. It paddles well heeled over in solo paddler style. The flat bottom is lifted out of the water reducing wetted surface resistance. The waterline is lengthened increasing hull displacement speed. And the long narrow bow provides the directional stability of the tail on a kite. I often use the mast partners as a back rest when paddling. When traveling long distances in the sun the water jug is wrapped in a towel held on with a shock cord to keep the water from getting hot.

The light nylon hoop tent is made from the same fabric store nylon as the sail. With a tent I get to recline in the boat all night as well as all day. The night this photo was taken I lay awake listening to the roar of thunder and watching the flash of lightning from a storm passing a few miles away. Ideally the boat should be anchored and free to move in a circle to keep its bow into the wind but I haven't got beyond the "tie it to something solid" stage yet. I tie a stone to a line on the transom and toss it out in the water to keep the hull from rubbing on the rocks.

 

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