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Folding Kayak

( Including complete plans and instructions)

My friend Bob Williams built one of these folding kayaks from plans that were printed in Popular Mechanics about forty years ago.  It was also published in Boy's Life and Field and Stream.  He bought a reprint from a magazine in 1978, and has had the plans ever since.  After twenty two years the boat came to be built in kind of a curious way. 

Bob was interested in a houseboat that Rags Ragsdale of Florence Oregon had built and later written up in Messing About In Boats.  He called Rags to talk about it, and during the course of the conversation, happened to mention the folding kayak.  Mr. Ragsdale then informed Bob that he, Rags, had bought the very first set of plans from the original designer, Robert Romaneck.  Rags went on to reveal that he had built over fifty of the things, and was very enthusiastic about the design.  Bob could not help but catch some of that excitement, and the rest is history.

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Here I am at the helm of this stable and fun little boat.

Bob called me up the other day and invited me to accompany him on the christening and maiden voyage of this new folding kayak.  We took her down to the Guadalupe river near his home in Kerrville, Texas, and after unfolding the boat, each enjoyed a brief cruise.

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Assembly is easy

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Unfold

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Pop in spreaders

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Drop in the seat

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Pick up (only 40 lbs.)

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:Launch

What follows are the photos, diagrams and instructions as they apeared in the original Popular Mechanics' article

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It floats!

NOTE:  I should mention that Bob built his folding kayak 12 feet long rather than the specified 10.

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Click here for a zipped version of the plans: thanks to Bryant Owen

Folding Kayak

By Jess E. Rathbun

It’s not fast, it’s not roomy and you won’t find many practical uses for such an outlandish craft. In fact, this center-folding kayak has only one feature to recommend it. It’s fun. At $15 apiece, you can afford to make one for every member of the family. And you can tote a whole folded fleet on top of your car.

Construction is also unorthodox. Instead of using screws, nails or other common fasteners, you "tape" the boat together with canvas and contact cement. No metal parts are required.

Materials List

Plywood (Exterior grade AA or AB)
     1 pc. 1/4" x 4' x 10' Body panels
     1 pc. 1/4" x 9" x 4' Floor board
     1 pc. 1/4" x 9" x 14" Back rest
     2 pcs. 1/4" x 8" x 15" Paddle blades
     2 pcs. 1/2" x 1' x 2' Spreader boards
Lumber  (All hardwood)
     2 pcs. 1/4" x 1/2" x 6' Inside strips
     2 pcs. 1/4" x 1/2" x 10' Outside skid strips
     1 pc. 1" x 6' dowel Paddle bar
Misc.    
     24-ft. strip of canvas 2-1/2 in. wide, cut on bias
     17-ft. strip of canvas 10 in. wide
     1 qt. contact cement
     Finishing materials (waterproofer, paint, etc.)

Built according to the specifications included here, the kayak will weigh only about 40 lbs. And will accommodate an average-sized man. However, as long as the correct proportions are maintained, you can shrink the dimensions to turn out a midget version or increase them slightly to gain a little more leg room.

While marine plywood may be used for the side panels, exterior grade AA (or even AB) will do just as well here. Canvas can be anywhere between 14 and 18-oz. weight, but should have a tight, close weave for easy waterproofing.

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Begin construction by cutting the four side panels from a 4 x 10-ft. sheet of -in. plywood. All these panels have the same outline, the only difference between the top and bottom pair being the cockpit cutouts. If you’re planning to make two or three kayaks, cut the required number of panels at one time so that you can use the first two as patterns. The rounded ends of each panel are squared off slightly to present a 1 -in. straight edge so that the canvas will go around from top to bottom without wrinkling.

Next, cement the x -in. inside strips and retainers to the panels, positioning them flush to the edge with the -in. face down. The strips are designed to provide reinforcement for the seat bottom-floor board, but also to form notches to hold the spreader boards. Taper the ends of these strips and the inner retainers so that you can remove and insert the spreaders easily. Outer retainers act as stop blocks and need not be tapered.

Once these are in place, paint the inner surfaces of the panels since they will be almost inaccessible once the boat is assembled. Be careful to keep paint off the outside surfaces for this will prevent the contact cement from adhering well.

To assemble, position top panels on bottom panels. Then, using clamps and a spacer block at teach end, mount the right-hand pair 3 in. from the left, as shown in the photo on the opposite page. You’ll have to cut the canvas edging strip at a 45-degree angle to the weave to provide the necessary stretch so that it will fit around curves without wrinkling. Apply cement to both wood and canvas surfaces, but do not cement the canvas which stretches across the gap between the two pairs of panels since this will stiffen it. pic1.jpg (11202 bytes)

CLAMPS AND SPACER block are used to position the two pairs of panels the correct distance apart so that the 2 -in. strip of canvas edging can be applied.

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INSTALL SPREADERS after "taping" edges of panels. These should be trimmed for a proper fit before the center gap is covered with canvas. Allow enough slack so that spreader may be removed for folding.

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COVERING GAP between the right and left pairs of panels is the last step before finishing the hull. Allow 2 in. extra at cockpit and fold it underneath.

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ARROW.gif (884 bytes) CUTTING OUT portions of the spreader will lighten it without reducing strength to the critical point. Note alligator treatment used to decorate the hull.

To apply the canvas edging, hold one end flat against the edges of the plywood and stretch it. Then, while it is stretched, fold the sides of the strip over both top and bottom panels at the same time. Do a short section at a time, overlapping joints in the canvas about 2 in. (Try a practice session with scrap plywood before attempting it on the boat itself.) After edging is complete, pound the cemented surfaces with a block of wood and hammer or mallet to insure a good joint, then let the cement set overnight before inserting the spreader boards.

Next, cut the spreader boards, check the fit and trim if necessary. However, keep in mind that there will have to be a certain amount of slack in order to remove the spreader boards easily. With the spreaders in place, cover the center gap with canvas, then remove the spreaders and cement the skid strips to the bottom. After making the seat and the double-blade paddles, waterproof the canvas and paint all wood parts.


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Here is the letter we got from Popular Mechanix
giving us permission to publish the article above

From: Joseph Oldham
12/02/99 09:38 AM

To:  Duckworks Magazine
Subject:  Re: OK to reprint?

All editorial material is copyrighted by us.  So technically, you cannot use any of our material without our written permission.  But since the plans are not currently available, I will give you permission to use the plans on your website for now.  If the situation changes, and we are thinking about reissuing many of our old plans, you may have to remove the plans at some future date.  Thanks for inquiring.    

Joe Oldham

 

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