How to Build Stitch and Glue

 

 

 

 

 

 

 

 

Sample page from the PDF I send out

The following article was written by Tom Gerds and Submitted to: Bryan Hansel

 for: Nessmuking.com 24 November 2008

by “Eskimo” Tom Gerds, Finewoodwatercraft.com

Alone on an island on Lake Jeanette halfway between Voyager’s National Park and Ely I read in amazement about a 10 ˝ pound canoe built by J. Henry Rushton in 1883. It was built for George Washington Sears popularly known by his pen name, Nessmuk. The Sairy Gamp is an inspiration to anyone adhering to the ideals of the “Go Light” approach to wilderness exploration. I had just finished building the stitch and glue kayak, which carried me to that island. It weighed 32 pounds, a fair accomplishment considering a Kevlar kayak, often thought of as the lightest material to build a kayak from, of comparable dimensions and capacity tips the scales at 40+ pounds. I share a kinship with Bryan’s, this site’s publisher, enthusiasm for Nessmuking and in this article will illuminate one path to lightweight paddling, the stitch and glue method of boat building.

The stitch and glue boatbuilding technique is not new. It has been used for several decades world wide to build everything from tiny paddle craft to 30+ foot power and sail boats. Using software, the designer creates the hull in 3 dimensions and the resulting panels or planks are “unfolded” so they can be cut from 3MM to 5MM marine grade plywood in the case of canoes, sea kayaks and other small watercraft.

“Unfolding” the panels is the process of lofting or projecting the panel so that a set of three dimensional lines can be correctly recreated on a two dimensional surface. Fortunately much of the computational work is done by the computer. The plank lines from the design program are then brought into a computer aided design (CAD) program and measured for layout purposes. Planks are cut with a saber saw and small holes are drilled along each panel so they line up with the mating panels. As wire ties are affixed in holes along adjoining planks, the planks are “stitched” together, the intended hull shape is recreated and temporarily held together until it can be glued. The seams along the planks are filled with epoxy putty then the holes left by the wires are filled. The hull is sanded down and sheathed in fiberglass. The composite of the plywood and fiberglass creates a sturdy and durable hull.

No building forms or backbones are required saving the builder the time and material cost for that project. No special workshop is required. Many simple canoes and kayaks can be completed in less than 60 hours and material costs can be kept under $300 with some smart shopping. It is hoped that this article will help you understand the process more fully and help launch a quest for your own personal Sairy Gamp.

The key to minimizing weight is having only as much boat as is necessary, less material means less weight to carry. Nessmuk knew this well when he proposed building such a craft to Rushton who accepted the challenge. The result was named the Sairy Gamp, a marvel in ultra light construction. Nessmuk, the intended paddler was described as a wisp of a man 5’3” weighing perhaps 105 to 110 pounds. His gear and provisions weighed around 26 pounds. The hull measured 9 feet long, 26 inches wide and 6 inches deep. It was made of lapstreak cedar and finished with oil and shellac. Nessmuk claimed it provided 5 inches of freeboard. It must have been highly maneuverable and its keel may have assisted tracking. I’ve recreated the design for stitch and glue, it checks out.

Nessmuk didn’t worry about having a hull sturdy enough to strap down to a car going seventy down the interstate. The Sairy Gamp was retired after one season of use and has been on display ever since. It would appear that long term durability was not as much a concern as with today’s paddlers. In this age of Gore-Tex rain gear, carbon fiber paddles and titanium espresso makers I know few 110 pound campers who can limit themselves to 26 pounds of gear even for a weekend trip. Most paddlers today would be uncomfortable in a craft the size of the Sairy Gamp. Many folks in Canoe Country tend to prefer boats which track well and get the best glide for their effort requiring a canoe with longer lines than the Sairy Gamp.

It is my perspective that the best boat design is the one that suits your requirements most of the time. When I design a canoe or kayak for someone I want to know about their previous paddling experience, what they expect to use the new boat for, their intended payload most of the time and their overall expectations.

From this information, I begin with the essential design elements of displacement, length, width and height. There are many fine stitch and glue plans and kits available, however, many designs are intended to appeal to a broad range of buyers regardless of the intent of the design. After extensive research, I bought plans for two different style kayaks. In both cases, given my weight (160 pounds) and anticipated payload I found both were more generous than I anticipated. Like Bryan I went off and in search of my idea of the perfect hull and quickly learned that one person’s ideal of a perfect boat is just that. Given the state of technology I felt I could assist homebuilders by providing exactly the set of plans they wanted had they designed it themselves for stitch and glue and wood strip construction.

Today I specialize in helping those folks who can’t find exactly what they have in mind and don’t have the time or inclination to master a new software program or the mathematical intricacies of hull design. It is a small niche to be sure, but my customers appreciate the fact that they can start building shortly after their plans arrive and they are getting exactly what they have in mind. Most have done their homework, made comparisons and some have already built other boats. I typically provide this service at a fee that’s comparable to a stock set of plans.

Bill Mason recommends a minimum 6” of freeboard for loaded canoes and it is a useful guideline I like to adhere to when designing canoes. Freeboard is simply the distance from the top edge or sheer line of the canoe down to the waterline measured midway between the bow and stern often at its lowest point.

Freeboard is less relevant for kayaks as waves simply wash over their decks. Regardless if it’s a canoe or sea kayak, any surface area above the waterline will be affected by wind and waves. In addition to freeboard, the waterline height measures how much of the hull is submerged below the water to the lowest point of the hull. The total weight of the hull, the passengers and gear equals the weight of the displace volume of water. The greater the load, the lower the hull rides in the water and less freeboard is showing. The center height of the canoe is the sum of its submerged height and freeboard above water. John Winters renowned designer describes a term “Designed Displacement” as the displacement intended for the best performance given the canoe’s purpose and there is a design waterline at this displacement.

Few canoe manufacturers provide this information and instead may list a capacity which according to Winters is a meaningless number. I give very high praise to the folks at Bell Canoe Works who provide us waterline and displacement measurements for comparison. To better illustrate the relationship between freeboard and displacement I will use the Bell Magic solo canoe as an example. It happens to be one of my favorite products in their lineup. The Magic measures 16 feet overall length, has a center height of 12.5” and will displace 240 pounds at 3” of waterline. The optimal load is described as 160 to 280 pounds. Capacity is described as 650 pounds at 6” of waterline.

Using the 3” waterline displacement of 240 pounds leaves 9.5 inches of freeboard above the waterline, 12.5” center height minus 3” below the water. If I subtract the optimal load from the capacity, which in this case coincides with Mason’s 6” minimum, I get a figure that may unscientifically be described as “reserve buoyancy.” You could carry more if you want and when you are spending the big bucks for a new ultra light boat, it sure is nice to know you could carry more if you wish! But do you really want to? Will it be more than you need most of the time?

When I create a canoe design in wood I keep in mind exactly what the hull is expected to float and can usually reduce the overall height of the hull. The reduction in height saves a considerable amount of weight for the homebuilder working with wood and fiberglass and makes it is possible to build solo boats comparable in weight to many commercial ultra lights. The Sairy Gamp gave five inches freeboard at its designed displacement. For the homebuilder using a design that’s exactly what is needed saves weight. If you find you need more capacity in the future, build a new boat. For the price of a new ultra light boat in the store you could afford to build three or four boats stitch and glue boats and still have enough left over to buy a pair of titanium sporks. After each build, your technique will improve and the resulting hull will be lighter.

Creating a shorter hull is another path toward weight reduction. A little creativity on behalf of the designer can make a shorter hull track better by placing a little less rocker in the stern than the bow. It helps make the canoe less bulky to carry and store. The width is another variable in the designer’s toolbox for weight savings. As a paddler is more experienced they gain a better sense of balance and will benefit with a narrower hull. A narrower hull requires less energy to push aside the water compared to a wider hull of the same length. Sea kayaks are fast and don’t require much effort to paddle because they are narrow. They can be narrow because the paddler sits on a seat that is just above the floor. Canoes are wider because paddlers sit in seats that are closer to the gunwale than the floor. Sitting higher creates a higher center of gravity. A wider canoe helps counter the momentum of a leaning paddler improving the sensation of stability. I was rather surprised how stable a sea kayak felt when I first paddled one. I marveled at how easy it was to paddle in windy conditions given the little amount of freeboard. During the same time, I happened to be reading about the sailing canoes of the late 1800’s. Paddlers of these boats sat close to the floor and used kayak paddles in canoes, which had low sides and were decked with wood or canvas. Today I paddle a low sided narrow open canoe and I sit on the floor with foam cushions and use a sea kayak paddle. I’ve reached my personal ideal for paddling a craft, which suits my needs and the conditions I paddle in. I also have a sea kayak, a tandem Kevlar canoe a small sail boat and a few projects on the side. “You can never have too many boats,” my friend Chris once said and there is a lot of truth to the statement.

Adding a few inches to the side of Kevlar canoe design adds little material weight or cost to the design but it can greatly increase the range of paddlers interested in it. Kevlar and carbon fiber materials have allowed manufacturers to create canoes of immense capacity with minimal weight penalty.

I purchased a Kevlar tandem in the days before Bell and recall reading the literature thinking I’m going to get my moneys worth by buying a 40-pound tandem that can carry 1,000+ pounds. When a company claims a tripping canoe paddles as nice empty as fully loaded I want grab the copywriter by the ear and take them for a paddle on a stormy afternoon on Lake Superior and let them experience the difference first hand. Although the claim may be plausible when the wind is dead calm, I can say with some authority that it always seems to be windier when paddling. While my Kevlar tandem is most excellent fully loaded it shows much too much freeboard when used empty with two paddlers. It is excellent for its intended purpose the BWCA trip fully loaded but performance and enjoyment suffers the rest of the paddling season for which it is used most often, just one of the compromises we all must make.

How do you decide what to look for in a canoe design? Initially it is an overwhelming challenge if you haven’t paddled many canoes or kayaks. I suggest first talking with experienced paddlers then get out and try as many models you can. There are no right or wrong answers and you will want to formulate some opinions as to what suits your needs.

Rather than getting too technical about canoe and kayak design, a few guidelines may be useful. Philip Bolger, an accomplished designer, summed up one important aspect when he said, “the joy of boats is inversely proportional to their size. The dwindling starts when you get to where you can’t carry it in one hand and the fishing pole in the other and keeps on getting worse from there until you get to the bottom-job and joker-valve stage.” There is no perfect boat that will excel in all conditions. Perfection is also in the eye of the paddler. What is suited for one will not be for another. Rather than write endless comparisons regarding the minutiae separating design strengths and flaws I give you a few quick axioms for your consideration.

Design Rules of Thumb

• A large boat will hold more than a small boat
• The bigger the boat, the more material required, thus more weight
• Lighter boats are easier to carry than heavy boats and will likely get used more frequently
• Wider boats will feel more stable than narrower boats given the same length
• To a point, longer boats will be faster than shorter boats of a given beam or width
• Less experienced paddlers will feel safer in a wider boat
• Experienced paddlers tend to prefer a faster boat
• Stability and seaworthiness lies with the experience of paddler
• A decked boat will take on less water in rough conditions than an un-decked boat
• Given the same design, sturdy construction will withstand more punishment than lightweight construction.

My first experience paddling a solo canoe was taking my turn to fill the five gallon pickle bucket with lake water in a fast and slippery Sawyer Summersong measuring 15”6” x 27.” It is quite a tender boat to the uninitiated and was affectionately renamed the Summersault when on more than on occasion a person carelessly lifted the five gallon pickle bucket much too quickly to regain their balance. I recall vividly fearing for my life in that Summersong heavily loaded with gear and whitecaps were building on Big Sag. I truly expected to capsize but the fear gradually subsided when I realized the narrow hull was amazingly stable in the chop and I was rapidly pulling away from my two companions in the Kevlar tandem.

Before I built my sea kayaks, I had bought a sea kayak paddle to use in the Summersong and it’s about the closest a canoeist can get to sea kayaking in feel and speed. I had to stop on several occasions to allow them to catch up. We were dodging from the lee side of one island to the next on our way to the narrows. At first, I feared hitting those wind swept openings with the highest whitecaps, but I actually enjoyed riding the waves by the time we safely made the narrows. I learned how to lean it and brace with the kayak paddle and found it served quite well in the trout fishing rivers of Northern Wisconsin and Southern Minnesota

While a wide flat floor will feel stable, it will only do so in calm conditions. In waves the flat profile will follow the wave’s profile, an especially frightening situation when broadside to a train of waves. I learned that lesson in a short tubby aluminum Smokercraft tandem that we joked was as wide as it was long. It was frightful in choppy waves and difficult to portage because one’s arms were so outstretched to grab the gunnels.

Another valuable design lesson I learned right after acquiring a used Kevlar Wenonah Minnesota II 2nd from the Sawbill Outfitters outside Tofte. I drove up from the Cities and had the weekend to spare so the outfitter told me about the Freer chain of lakes in the Superior National Forest and I spent the rest of the weekend alone with my new acquisition. I paddled around and found a remote site and learned how to carve a turn and handle a big tandem solo. It was a handful when any breeze picked up. Even with two people and no gear, it’s a handful on a windy day but it excels with a full load in the BWCA, which was the primary reason for its acquisition.

If your budget allows, always consider two solo boats for two people. My experience is that many folks buy a tandem only to find one person will want to paddle more frequently and a partner is not always available leaving the tandem unused. The solo boat gives one the freedom to go paddling whenever and two solo boats give each person a degree of freedom eliminating any frustration with the person at the bow or the stern.

In our BWCA trips, the solo boat is often the most requested. Especially on a long and windy trip, the solo paddler has nothing more to focus on than the next destination and the sights around them. Any stress of wondering if the other person is pulling their weight is nonexistent. Actually it’s expeditious to build two boats at once space permitting. The incremental cost of materials is practically insignificant. The most significant expenditure is your time. Getting set up to cut or glue takes the most of the time. It doesn’t take much more time to cut the pieces for a second boat. And while one is waiting for the epoxy to cure on one hull one can be applying epoxy on the second craft.

The advantage of building from a kit is everything arrives at once and the planks are precut. The advantage of building a stitch and glue boat relative to other methods is that it is fast. The typical builder can complete a stitch and glue boat in about 40 to 60 hours. I first built from plans and sourced the materials locally. This reduced my out of pocket expense by about $275 dollars or enough to buy enough material for a second boat.

Determining the number of planks to use in a design and lining them off for the length of the hull takes a practiced eye. I use the term plank instead of panel to describe the long narrow pieces of marine plywood used to build the hull. The goal is to provide a fair run which will part the water easily given the load. Typically, the planks along the keel line, which become the floor, will be wider. I will use narrower planks where the sides meet the bottom to create a more graceful curve below the waterline. Fewer planks results in less assembly time however the hull may not be hydro dynamically efficient as a design with a more rounded form. I use ten planks to create most canoes as which results in a very attractive set of lines. .

Two common terms one encounters for wood sea kayaks is single and multi chine. Kayaks with four planks, two for the floor and one on each side are called a single chine model or hard chine and a multi chine model will have more, typically 8 total planks. A chine is simply the hard edge or seam line where the panels meet. The more planks you have the closer you get to a fully rounded shape. The cedar strip canoe is a fine example of this. The narrow strips fitted tightly and properly sanded can make a nicely rounded surface. It’s my opinion that a well designed and finished stitch and glue hull will perform as well as any other for 90 percent of the paddling public.

Marine grade plywood 4 millimeters thick is the ideal material for strength, beauty and durability. The sheets are generally 4’ x 8’ and I layout the planks so that two sheets are all that is needed for most solo boats up to about 15 feet 5 inches in length. This is done by cutting the sheets in half lengthwise. A scarf joint is used to create two sheets 24 inches tall and 192 inches long. A scarf joint is made by shaving a diagonal slice off the ends of the plywood being joined An 8 to 1 ratio is used meaning the diagonal shaved away will be 8 units wide for ever 1 unit if plywood thickness. For 4 MM plywood the scarf on each piece is 1 and Ľ” wide and is shaved away with a hand plane. One diagonal is lined up with its mate and glued with epoxy. The resulting joint is as strong as the surrounding wood. Longer hulls simply require scarping additional material to achieve the desired plank lengths.

Some critics suggest the stitch and glue technique makes a less beautiful boat than other techniques. I don’t find them any more or less so. Regardless of technique or design used to build a wood boat any boat be mangled by the sloppy builder. I applaud those who find the time to make masterpieces of paddling art however I get even more when I see the efforts of those first time builders who get it right. Wood strip builders are faced with the scarcity of prime quality old growth western red cedar and substituting less prime species resulting in a heavier wood with less attractive grain.

Sawhorses and any stable flat material can be used to create a suitable cutting table. A tape measure, yardstick and pencil are used to draw vertical station lines every twelve inches perpendicular to the long edge of the plywood. The plans then show where to mark the plank lines at each station. A long flexible batten is used to “connect the dots” so to speak to create the plank outlines – an 8’ piece of quarter round edge molding works well for this. Numbering each plank and marking the bow and stern ends will eliminate confusion during assembly. All lines are drawn on one piece of plywood and the second piece is fastened securely underneath using clamps or double-sided carpet tape. Rough cut both pieces simultaneously, about 1/16” outside the lines with an electric saber saw. Shave away excess material down to your pencil lines with a hand plane.

1/8” holes are drilled every 6” inches along the keel line and edge that will be joined to the next plank. Successive planks have the holes drilled to align with the previous plank. Wire is cut in 3 to 4” pieces and inserted to “stitch” the planks together temporarily until the seams are filled with epoxy putty. The hull is propped up or supported to help maintain the desired shape. Wires are tightened or loosened to facilitate alignment. At this stage, it is sometimes necessary to remove wires and shave away wood if there are issues with binding between planks. This can be caused if the plank lines were drawn or cut incorrectly. Long narrow gaps too large to be filled with epoxy alone can be fitted with wood. Take your time aligning the hull. Often I will wire up the panels, make some preliminary adjustments and come back to it at a later time to make final adjustments before mixing up the epoxy. When the stitching is done, next comes the gluing.

I tape off the wood adjacent to the seams I’m gluing with epoxy. This cuts down on the time to fill the seams and significantly reduces sanding excess epoxy later. It makes a neater job and less epoxy is wasted. Epoxy consists of a resin and hardener and is an excellent water resistant adhesive for bonding wood and is quite hard when fully cured. Always use latex gloves when working with epoxy and read all the safety data. Wood flour is added to the epoxy stiffening it to a peanut butter like consistency and a plastic spreader is used to fill in the seams. There is a limited time before the epoxy starts to cure so small batches are mixed as needed. Work the epoxy into the seams. I generally remove the tape before the epoxy cures completely. After the epoxy holding the hull together cures, the wires are removed and the remaining holes are filled. All excess epoxy is removed in preparation to glassing the hull with fiberglass cloth.

An orbital sander makes quick work of removing excess epoxy especially as the run of the planks offer a relatively flat surface. Hand sand along the seam lines as the orbital sander may remove material rather abruptly on these edges. Take your time the objective is to have a smooth and attractive surface for glassing. Fiberglass cloth does not lay well over sharp edges so one wants to have a gentle curve on the seams where planks meet.

At this stage the process for finishing the hull is identical to that described by Bryan in his wood strip sea kayak building articles and that will assist you if you have never done that previously. I’ll wrap up this article with a few guidelines to help you achieve lightness in your technique.

§                       Consider building only as much boat as you need. After I built a lighter boat, I found I tended to carry even less gear.

§                       Break from tradition. Use a sea kayak paddle in your solo. Tracking or straight-line motion is virtually a non-issue when you paddle on both sides.

§                       Consider dispensing with the fill coats of epoxy on the inside of a canoe. It won’t have a glass smooth finish but it saves weight and leaves a little texture, which can be less slippery.

§                       Consider painting instead of varnishing. Yes, it’s a shame to cover all that beautiful wood but a coat of paint takes less time than applying three to five coats of varnish and will weigh less.

§                       Consider lighter glass. Most kits and plans specify 6-ounce glass which is appropriate if you regularly run over rocks or float a heavy load. I’ve settled on 4-ounce glass and one client 3.5 ounce with success but these are not expedition duty boats.

§                       Use foam pads on the floor for a seat instead of a cane or molded seat. They weigh less I don’t feel any less comfortable. Using ash for canoe trim is a heavy tradition.

§                       Dispense with the beautiful book matched breast hooks and fit a hand sized piece of dowel which will double as handholds or tie downs and reinforce the mounting points, less beautiful but lighter weight.

§                       Consider reducing the dimensions of the gunnels if you plan on using hardwoods. The dimensions commonly suggested for traditional wood canoes are too generous for fiberglass and plywood composite builders. I suspect one could do away with much of the trim on a stitch and glue canoe and it would be fine in the water. It’s lashing the canoe to the car for a trip down the interstate that requires the strength.

Going forward, I plan to use much lighter woods and possibly composites. Softwoods will obviously suffer more dents and dings but I don’t think it will mean any more work than keeping ash looking nice.

Some stitch and glue builders use 3MM instead of 4 MM plywood. I use 3 MM on kayak decks but haven’t made the plunge of using it for hulls. In all cases, I always add additional cloth to the bow and stern edges, which are more subject to abrasion.

Do not forget flotation! A properly finished stitch and glue boat when capsized will not likely sink but it absolutely will NOT support you or your gear.

You may be wondering whether building your own ultra light boat is within your capabilities. Without a doubt: with the inspiration, motivation and the right set of lines, anyone can create a boat they can be proud of paddling. With the stitch and glue technique, a vast range of hulls can be designed to suit your unique requirements. The material costs are quite low and the resulting craft can be built quite light and in less time than other common methods. If you are looking for a unique design or personal one to one assistance don’t hesitate to look me up