Building the Rushton Catboat
The Design
I found the lines for this 15-foot Rushton catboat in a reprint of Henry Rushton's 1903 catalog that was published by the Adirondack Museum and The Wooden Canoe Heritage Association in 1983. Rushton lived and worked in Canton, New York State, just to the north of the Adirondack Mountains, an area that in the late 1800's saw an explosion of tourism. This period marked the beginning of outdoor recreation in America and trains and steamboats connected the Adirondacks to the cities of Boston, New York and Philadelphia. Rushton made his name as a designer and builder of very lightweight rowboats for hunters and fishermen. The Adirondack guideboat, one of the most interesting American boat types, originated in this region.
Frankly, I was surprised to see a sailboat in Rushton's catalog, and I have no idea if his company ever built this particular design. But he published a lines drawing and a rendering showing her sailing rig, inboard profile and plan, and what attracted me immediately was her whitehall-like hull. Rushton's catboat seemed to strike a balance between the beaminess of a traditional cat and the rowing qualities of a whitehall. I was convinced that this would be a forgiving sailboat that could also be comfortably rowed when the wind died: the perfect compromise.
I searched for plans for this boat at the two major maritime museums with significant collections of Rushton boats: The Adirondack Museum in Blue Mountain Lake, and The Antique Boat Museum in Clayton. Neither had any material on this particular boat, so I decided to enlarge the lines drawing to a one inch to the foot scale on a copy machine and scale the offsets. Obviously this would result in inaccuracies, but because I would be lofting the boat full size I would be able to correct any errors and arrive at a set of full-sized lines that would be very close to Rushton's original.
Marc Bauer, a naval architect and colleague, had listened to me extoll the virtues of this boat and unbeknownst to me he had drafted the lines using traditional methods except for using AutoCAD instead of paper and pen. Then he measured each station at each water line and buttock to build the table of offsets. He sent me this material in the summer of 2007 just after I had reached an agreement with a client for this boat. I lofted the boat to Marc's offsets and interestingly, though his offsets laid down very fair waterlines and buttocks, the diagonals would not quite resolve and so I had to do some work on the lofting reconciling these discrepancies. I produced a corrected table of offsets.
Rushton's catboat features a plank keel, five inches wide amidships, tapering fore and aft to a 1 and 1/2" wide stem and deadwood. The bilges are full amidships, which should give this catboat good stability when sailing, but run smoothly to a slightly hollow entry forward. Aft the hull bottom rises up sharply to the classic wineglass transom so characteristic of whitehalls. Her load waterline should come right to the base of the transom, making her effectively a double-ender in the water, which means she will move easily under oars.
I like lofting boats on large rolls of high quality paper (which I get free from a printing company). The paper is easy to erase but most importantly I can store all my boat loftings in rolls, much easier than saving sheets of plywood. For picking up shapes I lay my paper lofting down on my mould stock and push a pin through the lines I want to transfer. I then connect the pin pricks on my material with a batten. Sometimes I will loft the body sections and the profile of the stem and stern on mylar. Being able to see through the lofting makes it easier to position on mould stock, or see how to best use material for a forefoot knee, etc. (Note: I loft boats on paper and mylar for amateur boat builders, see my website for more details).
My setup for the Rushton catboat was typical, with pine moulds set up on a ladder frame made of 2x6's. I decided to plank her with 6mm (1/4") okume marine plywood, with the laps glued with epoxy. I used pine ribbands 3/4" square, and I took the time to arrange the ribbands to lie along the planks lines. They would serve as the backing for clamping the laps, which would be 3/4" wide. The ribbands would also support the thin plank edges when I was beveling the laps.
For glue I was going to use general purpose epoxy thickened with wood powder so that, spread along a fifteen foot long plank, it does not drip off the lap. This would be applied from throwaway pastry decorating bags. These are plastic, cone-shaped bags that are normally filled with frosting and fitted with a tip (zip-lock freezer bags with the corner cut off serve the same purpose. Ed.). The builder simply squeezes out the material in a controlled bead. However, twenty years ago I discovered Smith & Company's Tropical Hardwood Resin (now called "Oak and Teak Epoxy Glue TM"). I had used this on some hard-to-glue wood, and when I built my first glued lapstrake boat, a whitehall from the Baker Boat Works catalog, I found this resin handy because it is THICK. It is thicker than honey and I didn't have to worry about thickening the epoxy mix with an additive.
Next: Beveling the Laps and Cutting the Gains
Douglas Brooks (www.douglasbrooksboatbuilding.com) is a boatbuilder, writer and researcher specializing in the construction of traditional wooden boats for museums and private clients. He lives with his wife Catherine in Vergennes, Vermont.
© Copyright 2007 by Douglas Brooks
