Archives for 2008

Setup is always a boat building milestone. Whatever is used to define the boat’s shape gets affixed to a building base. Shape is usually defined by frames, forms, molds, bulkheads, sometimes temporary, sometimes an integral part of the structure. This boat uses the two watertight bulkheads and the mid-frame to define the shape. They are integral components, not temporary shape forms.

The building base for the 1:1 version needs to be any simple flat platform that is 12 feet long, about a foot wide, and on legs that provide a convenient working height. For the model, I used a strip of composite board. Part of one of the drawings is glued to the block to make parts placement accurate. A few strips of wood provide anchorage for the bulkheads and frame. The parts are placed on vertical boards to allow access to the hull interior as it is being constructed. This technique is used for the 1:1 version as well.

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A renown naval architect, Howard Chapelle, advised that every boat shop needs a “moaning chair” where one can sit and look at a problem and think about how to fix it. It’s moaning chair time. Woodworkers often lament the way wood behaves when it is cut. Just after cutting the elliptical openings in the bulkheads, s-p-r-o-n-g! They both turned into curly things.

Several attempts to reflatten by steaming and clamping did no more than delaminate them. The resolution was to remake them using thicker boards. Then after all the cutting was completed, I milled them to the correct thickness.

This is one of those areas where it’s good to learn the lesson on a model. It turns out that builders of the 1:1 version have reported similar problems making these bulkheads.

The extra parts in the picture are for the hatches in the bulkheads. The bulkheads are intended to be watertight, providing a flotation chamber in each end of the boat. The plans define a hatch which uses a screw mechanism and gasket to close the opening. Or, one can buy a ready made closure from a boating supply outlet. I chose to mimic the one in the plans.

The screw is operated by a knob. Let’s make one. Of course it’s too small to operate like the 1:1 version, but can be made to look like it.

This made a good excuse for doing some refurbishment of an ancient Unimat lathe. It will never be a good metal turning lathe again, but it’s good enough for this task.

The port closures turned out very well. They can be installed and removed much like the full size version. These details add a “Wow!” factor and help define “fine scale.”

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Unlike many canoes, this one has a flat bottom. It is very much like a dory bottom, flat, wide, and with a very slight bit of rocker (fore and aft curvature). One of the benefits of this sort of bottom is relatively high “initial stability,” meaning that it isn’t as tippy as a narrow round bottom or v-bottomed boat might be when you first step in to it. It’s also very easy to construct.

We won’t find boards wide enough for the full width, nearly 15 inches. So, we edge glue as many boards as needed to make up the width. Due to lumber availability, the 1:1 version will likely require 3 boards, and that is what I did for the model. These joints are probably the most critical in the boat. They are edge joins of boards that are 9/16 inch thick, and are fastened solely with glue. The edges have to mate as close to perfectly as possible. They will be a good place to use a #8 jointer plane.

The photo shows how I simply cut out parts of the drawings and rubber cement them to the actual parts for cutting. The technique minimizes a lot of measuring and the errors that come along with measuring.

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