F1 Kayak, January 2021
Until 2021, most of my kayaks were home-built out of wood with epoxy and fiberglass. Brian Schultz of Cape Falcon Kayak created a detailed instructional video course for building skin-on-frame kayaks. For me, that was the ideal remote class for a pandemic-lockdown lifestyle. I was attracted to building these kayaks because I enjoyed DIY projects and the kayaks’ low weight and customizable features were not available in other types of construction or mass-produced boats.
I enjoy surfing waves, and Brian offered a surf-optimized version for the F1. My kayak was configured for a 140 pound, day-tripping paddler. The length was cut down to 13 ft 9 in. I intended to use this for short paddles in rough water and surfing 3-5 ft ocean waves.
I watched the videos to the end multiple times before starting to cut wood. All the wood was kiln-dried from a local lumber store. I had all the tools I needed to dimension the lumber and cut the mortises. With kiln-dried white oak ribs, the task of bending and inserting ribs into the mortises was a disaster. Cracked ribs and mortises outnumbered the good ones at first, but at the end of the day, I had 20 ribs in place. The cooled ribs needed shape adjustments and I used a heat gun to coax them into a smooth transition from bow to stern. The rest of the build, lashing the keel and stringers, installing the bow/stern stems, applying Danish oil, skinning, dyeing, and coating the kayak were uneventful.
Fabricating and installing the leather tiedowns were as excruciating as most bloggers discovered. I ordered the leather strips from Cape Falcon. The stretching and narrowing of the leather so they would fit in the kayak’s gunwale was quite an effort. Pulling the leather through the gunwale holes required considerable strength, but since I was on the home stretch, it was tolerable. I added the requisite deck lines and a bungee across the forward deck as seen in the above photo.
For the maiden paddle, I waded out from the beach to knee-deep water and sat on the F1’s back deck, I immediately flipped over. I tried again and flipped again. I could not get into the boat until I launched from the sand. In flat water, the kayak felt tippy and tracked poorly. When I stopped paddling, it veered to one side exhibiting what Eric Jackson calls spin momentum. In two-foot quartering waves, it tended to veer into the waves. I needed to raft up with another kayak in order to get a drink out of my PFD. In short, it was a hugely disappointing day.
Consulting with Brian
Brian was very responsive in my request for help. With supplied photos and measurements, he diagnosed the problem to poor rib shaping, a consequence of using kiln-dried wood: the keel to back deck height was too high, the stern keel was too short and the center ribs were too rounded.
Fixing the Problem
I had to reshape the ribs! Sadly, I removed the deck rigging, beautiful skin and keel/stringers. Buy new green bending rib stock? No. The ribs were epoxied into the gunwale since many mortises were split during the original rib installation. Rather than cutting the ribs out and mortising again, I decided to reshape the ribs using a heat gun and clamps. After a few days of torturing ribs, I was able to achieve a better rib profile and correct rocker heights.
Did the Fix Work?
Hooray! The F1 now paddles like a dream, stable, tracks straight with no spin momentum. Rough water performance is great and it surfs and rolls up fine. It is amazing what small dimensional changes can do.
I constructed stiffer thigh braces out of cedar wood strips with fiberglass and epoxy reinforcement. The strips were edge-glued (with Titebond 3) over a section of plastic 4″ pipe that was bent to match contour of my thigh. The curved wood surfaces were faired with sandpaper and fiberglassed. This process is similar to building a wood strip kayak. The knee braces were attached to the gunwale with two right angle brackets. An additional right angle bracket was used to secure the front edge to deck beam #3. Minicell foam was used to fill in the gap between the thigh brace and inner deck skin.
I did not like my butt deforming the kayak skin so I constructed a cedar wood-strip seat by edge-gluing wood strips over a form consisting of a 1/32″ thick HDPE sheet which was stapled to the stringers and keel. The HDPE sheet was allowed to dip below the ribs so the wood strips would be slightly lower than the ribs. After scraping off excess dried glue and fairing the wood, two layers of 6 oz fiberglass were epoxied over both surfaces. The seat was then screwed to the stringers and keel with #6 self-tapping screws. I feel a little safer now that a great white shark has to go through wood and fiberglass before taking a bite on my butt.
I replaced the 1/2″ foam mat with a 1/32″ thick HDPE sheet. To hold down the front edge, I used a propane torch to bend tabs that hooked onto the ribs. The rear edge is held down by the wood seat. Strap ties hold the side edges against the ribs. The HDPE is slippery and made foot-entry a breeze–no hang ups on the ribs or rubbing against the kayak skin. By eliminating the foam mat, the legs are 1/2″ lower to improve stability. The HDPE sheet was purchased from Tap Plastics.
I found that the large NRS float bags fit nicely fore and aft.
West Greenland Kayak, June 2021
I wanted a rolling kayak to learn and practice Greenland rolls. I chose the standard size Cape Falcon West Greenland design with a 1/4 inch reduction on the gunwale height.
Most of the wood came out of the scrap pile from building the F1 and previous strip kayaks. I scarfed the gunwales to length and bought more kiln-dried white oak which were in a bargain section of cutoffs. My intention was to use the white oak for the cockpit coaming and order green white oak for ribs from a Wisconsin mill. I ordered the green white oak and started to process the other wood pieces. A month later, I had the cut list completed, but no oak yet, so I decided to try my luck at bending the scrap kiln-dried oak. To my surprise, I was able to shape all of the ribs without any breakage. What did I do right? I am not sure, but this time, I soaked the wood for five days and used a bending fixture that consisted of a 36 inch steel strap from Simpson Strong Tie. Wood handles spaced a rib length apart were screwed to the strap. I got the idea from the book by Lon Schleining, “Wood Bending Made Simple”. He calls it a compression strap since it limits the dimensional stretching on the outside bend and forces the inside bend to compress. Initially, four ribs were fitted to four compression straps. Five minutes per rib gave me sufficient time to steam, bend and reset the wood handle for the next rib length. The ribs still were not as pliable as those shown in Brian’s video, but I bent the ribs over various curved shapes similar to the cockpit bending fixture. I had 100% success rate in bending ribs, so I cancelled the order for the green bending oak.
To protect the mortises, I clamped wood pieces on both sides of the gunwale. No mortises split during rib insertion.
For the masik, I glued three scrap pieces of ash instead of buying new thick lumber. After shaping, the masik withstood the force of my standing on it. The foredeck stringers looked too scrawny to support someone standing on them, so I epoxied fiberglass tape on the underside including the tapered end which rested on the masik. This added tensile strength in case the stringers were stepped on. Wherever there was a doweled joint, I filled the gaps with thickened epoxy for more strength and waterproofing.
I used the adjustable Werner Foot Brace so the kayak could be paddled by others. The aluminum extrusion was cut down to fit in the kayak and to reduce weight.
I found the Seattle Sports float bag set fitted nicely.
I ordered the Spirit Line 840 X-TRA skin kit with additional 1/2 order of polyurethane. This was my third instance of applying Corey’s goop, so I felt confident completing this tricky procedure. I discovered that I could quickly pop the bubbles using a 4 inch foam brush. I did overlapping, light strokes from bow to stern with the brush. The brush was in continuous contact with the poly during each pass. This technique is essentially the roll and tip method for applying surface coatings.
I did not like my butt deforming the kayak skin so I constructed a cedar wood strip seat by edge-gluing wood strips over a form consisting of a 1/32″ thick HDPE sheet which was stapled to the stringers and keel. The HDPE sheet was allowed to dip below the ribs so the wood strips would be slightly lower than the ribs. After scraping off excess glue and fairing the wood, two layers of 6 oz fiberglass were epoxied over both surfaces. The seat was then screwed to the stringers and keel with #6 self-tapping screws.
In lieu of the 1/2″ foam mat, I installed a 1/32″ thick HDPE sheet. To hold down the front edge, I used a propane torch to bend tabs that hooked onto the ribs. The rear edge is held down by the tabs bent toward the bow to hook on the ribs. Strap ties hold the side edges against the ribs. The HDPE is slippery and makes foot-entry a breeze–no hang ups on the ribs or rubbing against the kayak skin. By eliminating the foam mat, the legs are 1/2″ lower to improve stability. The HDPE sheet was purchased from Tap Plastics.
The test paddle was satisfactory. With the boat in flat water, I could sit on the back deck with the paddle as an outrigger and slither easily into the ocean cockpit. The boat felt less stable than the F1, but with additional butt time, I expect to paddle it comfortably in rougher waters. The second time in the boat was in a class with Greenland rolling instructor Helen Wilson. I managed to perform the balance brace and simpler rolls: storm, forward sweep, reverse sweep, butterfly, and shotgun with ease. While the kayak’s shape is elegant, the skin is a bit rough when seen up close, but I get frequent compliments on the water and even while driving with the boat cartopped. Final thanks to Brian for creating excellent video lessons to guide the building process.