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a couple of tips
By:Paul Jacobson
Date: 2/1/1999, 8:51 pm
In Response To: Re: making my own kayak plans for river kayak (Nolan Penney)

Two points, a least.

> A batten techique is so easy I don't understand why the kit makers don't
> crow it at the top of their lungs. You mark the wood with one foot spaced
> lines. And then from the bottom of the sheet of wood you measure up the
> appropriate distances and mark. Then use a pin or nail to mark those
> locations. Take a piece of nicely flexible wood that is consistent (or any
> other consistent material for that matter), bend and pin it against those
> marks, and draw the curved line that results. VERY pretty! and oh so
> quick. I spent days fighting to mark the full sized templates, and one
> afternoon doing it with battens. You couldn't pay me to go back to full
> sized templates.

A technique from basic geometry that should apply easily to this process: When you bend the batten over these points you have a certain amount of `play' in the batten. When yo line up the batten for tracing an edge for a panel, mark on it ( a pencil mark is fine) where it touches the ends of that panel. Now, when you go to establish the curve for the panel that will match up with it, use the same batten, and be sure the end marks fit exactly. This may mean tugging on the batten, or pushing it so that it is a bit wide of your marks. Either way, it is imporant that the end points match sp the panels will have the same perimeter, or edge length.

> About a 12 panel s&g, I agree with the others about either backing off the
> number of panels, or switching to strips. Trying to wire up 12 panels in
> any sort of consistent and symetrical manner sounds like a nightmare at
> best. I doubt you can do it, honestly. My MillCreek has but five hull
> panels, and suits me just fine. And five panels was enough of a cussing
> match in symetry for me. It's the nature of s&g to have hard chines, or
> hardish chines as my MillCreek has with its five hull panels. Hard chines
> have some advantages, so weight this and your planned usages against a
> rounded bottom which is far better suited to stripping.

12 panels for just the hull? If the hull has a beam of 24 inches the circumference of the hull will be about 36 inches. That makes each panel about 3 inches wide. You might as well make this as a stripper with 3 to 3 1/2 inch wide strips, instead of 3/4 or 1 inch wide strips. To do this:

Make forms as you would for a stripper, and mount them on a strongback. Establish the sheer line, or the line where the deck joins the hull, on each form. Measure around each form with a flexible tape measure. A cheap cloth tape such as that used by tailors is ideal. Get one at a sewing goods store for a buck or less. If you want 12 panels, divide that distance into twelve parts, and mark each form. Your center marks should land exactly on the centerline, or the center of the keel, and the areas on both sides of that should be evenly marked in exactly for 6 panels on each side, up to the sheer. (or Down to the sheer if you are building in the upside-down manner commonly used). Hopefully, you will discover that your forms are symetrical.

Now you can use these measurements to make your panels, laying them out on a wide shhet of plywood, or, you can cut a dozen rectangular strips that are at least, as wide as the widest measurement for a panel, and shape them on the forms until they fit. Or, you can do a combination of these.

While this may technically be considered a stitch and glue, you can hold the panles in place by nailing them with brads to the forms, or by using a few staples to connect them. You can stitch them together with wire in drilled holes, where needed.

As for the material for the panels: you can use plywood, or, if your panels are narrow enough, you could rip apart 2x4s into 1/4 inch, or 3/16 inch strips.

If you use plywood, most dealers will make a few cuts for free. If you can get them to rip a 4 by 8 foot panel into tqo panels that are each 2 by 8 feet (roughly) you can scarph those together to get nice strips that are almost 16 feet long and about 2 feet wide, and are VERY even in thickness. (less sanding) Rip these into strips that are a bit wider than you need.

Either way, since you are planning to make two boats, work on one side of the boat first, shape the panel to fit, then stack it on 3 pieces of plain, rectangular panel stock, trace the exact outline, and you can cut out pieces for the opposite side of the boat, and for the second boat. These pieces may need a little additional fitting, but that is quickly done with a plane, if you cut them just a tad large (spare the pencil line). If you have some cheap plywood you can add that to the stack and have a spare piece for a template to use for later boats. Assuming everything is symetrical, you should only need to have 6 panel shapes -- and two copies of each.

If you have rectangular panels and want to use your forms to determine their shape, tack two down the center line of the keel, Their common seam should be at the keel or centerline. mark where they extend over the hull forms and use a batten and pencil to determine the outside (curved) edge. Cut it to the line you have drawn, mount it back on your forms with a few brads, and wire the two pieces together at the keel. Take your plank for the next panel, lay it on the forms and hold it there with a few tacks, so that it overlaps the first panel slightly. With a pencil, reach under the plank and trace the edge of the first panel onto the plank for the second panel. You have to stop at each form, but for the most part you will have a continuous line showing you the inside edge for that plank. Use a batten to determine the outside edge, and cut as many of these as you will need for 1 or more boats. Attach with an occasional brad or staple, and wire to the first panels. You now have 4 panels for you hull, two on each side, and need to add 4 more panels to each side in the same fashion.

In his book `Ultralight Boatbuilding', Thomas Hill uses a similar method for fitting overlapping planks. Instead of using battens for the outside edge of the planks he uses chines nailed to his forms. Instead of cutting the inside edge to fit the previous panel, he overlaps them and glues them, forming a lapstrake hull that is very strong. You might want to look at his book for some nice pictures of his process, and consider adapting it as I have mentioned.

A note on this book. I see that www.amazon.com has two versions of the book, at two different prices. One is with `Frank Sletson' at $13.97 and the other is with `Fred Stetson' at $15.96 (and on back order). I have a feeling that they have the same book here, but a typo on Frank/Fred's name. Go with the cheaper one.

Hope these ideas help.

Paul Jacobson

Messages In This Thread

making my own kayak plans for river kayak
Robert -- 1/29/1999, 5:01 pm
Re: making my own kayak plans for river kayak
Nolan Penney -- 2/1/1999, 7:22 am
Re: making my own kayak plans for river kayak
Robert -- 2/1/1999, 7:50 am
Re: making my own kayak plans for river kayak
Nolan Penney -- 2/1/1999, 2:08 pm
a couple of tips
Paul Jacobson -- 2/1/1999, 8:51 pm
Re: making my own kayak plans for river kayak
Shawn Baker -- 2/1/1999, 10:54 am
Re: making my own kayak plans for river kayak
Robert -- 2/1/1999, 11:42 am
Re: making my own kayak plans for river kayak
Shawn Baker -- 2/1/1999, 1:45 pm
Re: making my own kayak plans for river kayak
Robert -- 1/30/1999, 2:47 pm
Re: making my own kayak plans for river kayak
Stan Heeres -- 1/29/1999, 9:58 pm