Building the Ultimate Expedition Kayak
Stripping the Hull
The first strip you lay on the hull will determine the shearlinethe line where the hull attaches to the deck. For this reason, I purposely set aside a set of strips with a cove, but no bead on them. They were laid cove-up (the easier way to strip, since the cove provides a handy "nook" for the glue to sit in between strips) so that the other, flat edge could later be planed and beveled to match the angle of the deck, thereby creating a nice, tight, flush seam. Some builders retain the bead-and-cove joint between the hull and deck, but since the hull and deck need to be handled and moved a lot before they are actually joined, this method risks the possibility you will inadvertently crack the fragile cove off of the shearline strips on the deck, resulting in gaps or an awkward fit. Having heard a few horror stories in this regard, I decided to leave the edge between hull and deck flat so it could be planed.
To lay the shearline, I started stapling at the middle station, placing the shear-strip where I wanted the joint to be. The stations for Joe Greenley's "King" have a fairly distinct edge where the hull transitions to the deck, so I simply followed this edge as well as I could without placing any abnormal curvature in the strip. First and foremost, you want the curve of your strip as it follows the shear to be natural and flowing, with no sharp twists or bends. Otherwise, it may disturb the aesthetics of the boat or make subsequent strips trickier to lay. Cedar strips are surprisingly bendable, but they don't like to bend abruptly at any particular place. The more natural, flowing, and gentle the curves, the better they fall into place. On the King, my shear-strips curved easily all the way out to the extreme tips of the bow and stern, so the lines turned out very gracefully.
Before proceeding any further, I sighted along the shearline to ensure the mold really was fair, without any bulges or dips. I found one station slightly out of alignment where the shear-strip seemed to dip in between the two surrounding stations. I fixed it accordingly by building up masking tape under the concavity of the strip until the curve appeared natural again. Otherwise, the rest of the mold seemed to be in near-perfect alignmentgive or take any minor cutting errors on my part, which could not be detected by eye.
With the shear-line in place, the stripping really got underway. I had two helpers: one friend to glue, and another friend to help me hold and press each strip into place as I stapled. Since my strips were 1/4-inch thick, I used 1/2-inch staples to attach the strip at each station, and 1/4-inch staples to bridge the seam between strips wherever they seemed to want to pull away from each other. Keeping the strips tightly together in this fashion is incredibly important if you want to avoid the possibility of opening up unexpected gaps when you plane and sand the hull later.
The process went as follows: Because I was using 11' and 13' strips on an 18' kayak, each strip was held up to the mold to determine at which station the butt-joint (the connection of two strips) would fall. The strip was cut to length, then carefully filed so that the butt-joint would be as flat and seamless as possible. Care was also taken to ensure that no two consecutive butt-joints ever lined up at the same station so as to minimize calling attention to them. Then a bead of glue (standard Elmer's Carpenter's wood glue) was run along the cove of the previous strip before the newly-cut-and-filed strip was set into place. A small piece of scrap strip was used as a "pusher" to push down on the strip while it was stapled at each station, thus ensuring a tight fit and protecting the fragile cove from being broken by any direct pressure from my fingers. Then, about halfway between each station, the strips were again pressed together to ensure there was no "wiggle room." If any wiggle room was detected, I pressed down on the strip tightly and used 1/4-inch staple spanning the joint to hold the two strips tightly together. Then, while two of us proceeded to size and cut the next strip, the third friend (with the glue) took a damp rag and wiped off any excess glue that had squeezed out along the bead-and-cove joint of the new strip. Having two helpers in addition to myself made this process go extremely fast. We were laying a new strip about every five to ten minutes. To ensure good color consistency on both sides of the boat, we alternated sides during every new strip we added. This way, as the wood color and grain pattern changed, it changed evenly on both sides of the boat. Alternatively, one could simply divide the bundle of wood beforehand and strip one side at a time. Regardless, the time committment would be about the same.
The most difficult part of the building process, by far, was handling the torque or rotational twist exerted on the strips as we began to round the side toward filling in the bottom of the boat. At the extreme stern end of the King, there is some mild concavity to its shape; this presented us with a big problem because the strips did not like to twist from a 45-degree angle (at the side of the boat) to near vertical (at the stern stem) in such a short space (about three feet). Often, the staples would pull back out, so I was forced to switch to finishing nails (an old canoe-building trick used by my friend Bryan). I pounded the finishing nails in until the small head of the nail just barely rested upon the top of the strip to hold it down. Pounding it in any further would have bruised or cracked the strip. Pounding it any less would have done no good since the strip could simply slide back up the shaft of the nail and still pull away from the station. Since the nails leave noticeably larger holes than the staples, I tried to use them sparingly.
Another trick which may be common knowledge, but which I didn't know (and so had to invent for myself) was to clamp the end of the strips where they overhang the stems, then attach a rope to the end of the clamp on one side to exert the necessary torsional force to rotate the strip into proper alignment at the ends. You can see in the picture how this works. I found it to be the most effective method for dealing with the twistier portions of the stern because it allowed the strip to be held in perfect alignment until the glue had a chance to dry thoroughly. In fact, I left the clamp on for almost two days and trimmed the overhanging strips at the stern last, after everything else was finished.
One last trick I learned that's worth mentioning is the convenience of using cam-buckle straps. At the extreme ends of the kayak, near the bow and the stern, the strips will sometimes twist hard enough to pull away from their stations. In order to keep the strips tightly against the station while the glue dries, just run a cam-buckle strap (like the yellow strap in the picture) around the hull and pull it tight to hold everything in place. If more pressure is needed in strategic areas, you can also slide a few strips under the strap to generate more downforce wherever it is needed.
Thanks to these strapping and clamping solutions, most of the stripping process went smoothly. In fact, there was only one major setback, and it happened when my friend Bryan started cutting off the overhanging strips at the stern: the block-plane grabbed the grain of the strips and the momentum added just enough additional pressure to the already-stressed, thoroughly-torqued strips to cause them to shatter on one side of the stern. The damage extended all the way through the strips, about three strips wide. Since the glue had already been setting for about five hours, we were forced to use water to weaken its bond so we could work the broken strips back out and replace them with new ones. I'm glad we addressed the problem as soon as we did. The glue had already dried to nearly the strength of the wood itself. As we pulled away the broken strips, we cracked one of the surrounding strips too because the glue simply wouldn't separate. However, with a lot of care and patience, we finally managed to repair all of the strips with new, virtually-undetectable replacement strips. Some builders probably would have ignored the problem altogether and just glassed over the break because it wasn't very visible. But I was resolved not to start off on the wrong foot, with an already broken hull!
When both sides were stripped up past the top of the first and last stations, I switched to stripping one side only, laying strips so they crossed over the ceterline by at least an inch. This I continued until that entire side had been filled in past the centerline of the boat. Then a stringline was set up to mark the exact center of the bottom of the hull, and the strips were trimmed back (using a dovetail saw, a chisel, a blockplane, and a file) to the centerline to produce a perfectly straight edge down the center of the bottom of the hull. Okay, mine wasn't exactly straight, but it was as close as I could get it after the edges of a few of my strips cracked off slightly. Once this was done, I switched to the other side of the boat to finish stripping and closing the gap back up to the centerline where the other side had ended.
The second most difficult part of the process was closing the "football"the last several strips before the bottom is finally closed up and finished. Each of the last few strips had to be carefully planed and angled to fit the long, slender gaps where the strips on one side curve in and meet the centerline running down the bottom of the hull. I took my time and tested the fit of my strips often before committing to stapling and gluing them in. All things considered, the results were superb. There were gaps, of course, because some of the sliver-thin tapered ends of my strips cracked off during testing, but some of the gaps could still be filled with the cracked pieces, and the rest could easily be filled with putty or epoxied sawdust.
Over the course of three days and a total of 22 hours (including stern repair time), the hull was finally stripped. It's an amazing feeling when you step back and look at the completed hull for the first time. The lines of the King are absolutely beautiful, and knowing that I had built them myself was an incredibly rewarding feeling.
A day later, I came back and planed off the strips where they covered the inside stems, and sanded them down even to form a nice, even keel-line at the bow and stern. Then I mixed up a batch of epoxy and sawdust to peanut-butter consistency so I could paste on the outside stems at the bow and stern. Three pre-drilled, evenly spaced screws held each stem in place while the epoxy dried. Eventually, these outside stems will be planed down and blended into the contours of the kayak, but since the weather had cooled off again, I knew it would take a day or two for the epoxy paste to set. In the meantime, I busied myself with pulling staples.
Pulling the staples is an exciting processfor the first 60 seconds or so. After that, it becomes a tedious, slow, time-consuming project. I used a good staple-pulling pliers with a flat nose to minimize the chances of bruising the wood while pulling staples. Some people pry the staples up with a knife blade or screwdriver, but I find this approach is far more likely to mar the wood. Having said that, sometimes the staples have sunk in so deep that the pliers simply won't do the trick and resorting to a knife or screwdriver becomes necessary. When you pull the staples, it helps to apply a little counter-pressure to the strips with your free hand so that you don't accidentally pull the strips away from the mold and crack them. Just be sure you don't press too hard or you might end up cracking the strips anyway.
After an hour and a half, I finally finished staple-pulling. At long last, the hull was ready to be faired with a block plane and sanding board. I knew it might be a slow, labor-intensive process, but a sense of excitement hung in the air. I could hardly wait for the next day to dawn.
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Copyright © 2004, Wesley Kisting