: I stitched-and-glued a Pygmy Arctic Tern 14 a year ago. I love the boat, I
: love having built it myself. Now I'd like to build a strip boat (having
: never done one before). In particular, I'd like to duplicate a touring
: kevlar boat I own and have paddled for a couple years. My question: how
: best to create the forms from scratch (without dissembling the original
: kayak) and then line them up accurately on the stronghold. -- Thanks, John

You can do this with pecil and paper -- or to be a bit more accurate, with pencil and cardboard -- and without the need for a CAD program for your computer.

The process is the same as that which a carpenter uses for scribing a shape or an angle that needs to be matched. You position a piece of cardboard, roughly cut to fit over the outside of your boat, and then trace along the hull with a compass (the tool for drawing circles, not the tool that points north), letting the point of the compass rest on the hull and the pencil lead make a mark on the cardboard. When done this way you need to rotate the compass so that the pencil lead stays the same distance from the hull at all times.

When you have the lines traced on your cardboard you then use this as a pattern, and reversing the position of the compass you let the metal point tace the line you have while the lead draws a line on a second sheet of paper corresponding to the original position of the hull.

That's the traditional way, but I think using a compass is a pain in the neck. I'd replace that with a pencil taped to a small block of wood which could ride along the hull for drawing the first shape. Then, instead of reproducing the original shape of the hull, I'd take that pencil and woodchip and tape it to a 1/4 inch chip of wood. That way the curve I would draw (this time I'd draw onto the wood I'd use for the forms) would give me a form that would be 1/4 inch smaller than the outside of the original hull. Then, when I applied 1/4 inch wood strips to these forms my finished hull would have the same outside dimensions as the original.

Setting up properly *before* doing this can be the difference between ease and disaster.

You want to start with a work surface that is relatively stiff, and longer than your boat will be. A box beam made of 1/2 inch or 5/8 inch plywood about 6 inches on a side, or a "T" shaped beam made by screwing a 2x6 along the center line of another 2x6 can work well. Alternatively, if you have an extension ladder (wood or aluminum) you can use that. Extend it out to the desired length and use a "C" clamp, or copious lengths of duct tape to insure it stays at that length through the project.

We will call this worksurface a "strongback". Don't worry if it twists, sags or otherwise is cockeyed. Set it on sawhorses, or make legs for it Use as many as you feel you need so that it is fairly well supported. Stretch a string down the approximate center of the strongback, and with a can of spray paint, lightly spray a mist of paint into the air above this. When you remove the string you'll find that the falling paint has outlined it, and the shadow left by the string is perfectly straight. You will align everything to this.

Most kayak plans are created with forms spaced a foot apart. Canoes are frequently made with forms that are spaced 18 inches to 2 feet apart. There is no magic number that must be followed for the distance between forms, however, the closer you space them the more you will have to make. You do not need to have the forms spaced evenly. Quite a bit depends on the exact design. You can put one at the center, surrounded by forms near the cockpit which are a foot apart, then skip forms entirely until you get near the last foot or two by the ends. With some designs this works fine. With others, you need intermediate forms to aid in defining the shape of the hull.

You will use a pencil to mark on your strongback where you are measuring or tracing the hull outline. Your building form will them be mounted at exactly this same location. Find the approximate center along the length of your strongback. Then place your existing boat upside-down on the strongback. Get a couple pieces of 2x4, lift the boat up and set it on those blocks, positioning the blocks on edge and near the center of the boat, (infront of and in back of the cockpit) so that the boat is fairly well balanced and at least two to 3 inches above the strongback. Use a plumb line (a string with a weight on it) or a square to help you center the bow and stern along the marked centerline.

While small boats are commonly built with the hull up (and the boat upside down) you don't have to do it this way -- but it may be easier. If you want to work the other way around, put the boat on the strongback right-side up.

At this time you may want to get some additional pieces of wood and screw them to the strongback (or clamp them to your ladder) so that they can serve as braces to hold the boat from slipping around.

Once the boat is mounted a few inches above the strongback you just need to trace your outlines for the stations, marking a line on the strongback to show where you obtained these measurements.

You may find it convenient to make an "easel" from a piece of plywood cut in the shape of a "U", which can slide along the length of the boat. Thumbtack your cardboard to this. The bottom of the easel will rest on the strongback, and when you trace your forms. measuring from the bottom of the easel will give you the height you will need to know to ensure the forms are mounted at the same height.

Once the forms are cut you attach them to the strongback and build from there. All the rest is practice.

This process is commonly used for creating replicas of boats that have historic value. Those boats created by ancient designers are now in the public domain. With boats that are currently in production you will of course consult with the owner of the design (assuming they are available) before starting on this and obtain permission, as others have previously mentioned.

Hope this helps

PGJ