F1 Kayak Build – 2022 PROJECT

I’m looking to add some extra value to my F1 student blog so will be emphasising things that I have done differently and or my failures. Early apologies to the “inch” people as throughout I will be quoting dimensions in mm.

Living on the Gold Coast, SE Qld, Australia, I am a world away from the source of the critical materials, good green bending timber and cloth and goop. So early in my journey I decided to try and use as much local and recycled material as possible, hoping as well that this might reduce the amount of international freight and transport energy that I needed to pay and use. As we go along you can judge how successful, or not, I have been.

At the Mens Shed where I will be doing the bulk of the build, we have ready access to a lot of scrap timber from a stair manufacturer. The bulk of this is kiln dried, (KD), Tasmanian Oak, (TO). TO is a mix of 3 relatively common Victorian hardwoods, and there is some literature from the local Forestry Departments that indicate that it is in the GOOD category for both bending and gluing. So I set out to see if I could work out a method of bending KDTO.

LEARNING TO STEAM BEND KILD DRIED TIMBER

The first job was to build the coaming bending jig, and for that I decided to hand make the required dowels as dowel posts, ( I’ve lots of time and this is a relatively relaxed journey), and screw them to a sheet of scrap ply that we also get from a local boat builder. I started with the posts 40mm wide but quickly realized that my clamps only had a jaw opening of 50mm and so would not fit the coaming and post, so cut them down to 25mm.

Hand shaping the dowel posts – FEB 22
Hand made dowel posts for coaming jig – FEB 22

My early attempts at bending the KDTO, varying the steaming time for 10mm thick stock, from 10 to 20mins, were a complete failure, so I needed to do some extra reading. Suggested solutions varied from simple soaking for up to 2 weeks, (I didn’t try this), to a regime of steaming for 1 hour, soaking for 2 days and steaming for the historically recommended 1 hour per 1” thickness. This last was from a US steaming expert, using KD US timber, (but obviously NOT Aussie TO). So with a very positive attitude I decided to give it a go. By this time I was limiting my bending samples to 5-6mm thick, and was test bending on the tight curve, 178mm dia, at the front of the coaming.

completed coaming jig and tools – ready for action
Some successful bends and run sheets – confidence is building – Apr 22
First bending trials KDTO – MANY fails and 1 success – YAHOO! – Feb 22

So with a light heart I proceeded to reduce a large supply of KDTO offcuts to about 50 samples, 5-600mm long x 32×5 or 6mm most with good grain orientation. For the final steaming I split the samples into groups to steam for 10, 14, 18 and 22mins, carefully numbered, wrote out a “run sheet” to try to keep me organized and proceeded to complete failure!

Almost every sample broke. I was devastated! But not beaten. Some more reading suggested that best bending happened at a moisture content of 20 to 25%, and cautioned that this was critical as was the temperature. So armed with a cheap construction moisture meter and a BBQ thermometer I planned a new campaign. I’d use 20 samples, 4 each for, 0, 60, 90, 120, 150mins soak, and steaming for 6, 8, 10, and 12mins, and make sure I was properly organised and fully document the results.

Interestingly, the no soak, 8 and 10min steam samples bent quite well, all the 60, 90 and 120 soaks broke but all the 150 soak samples bent perfectly even though they all had minor imperfections of knots and keno veins, and the last at 12min steam was the first time that I had felt that the bending was in the plastic rather than elastic range. So at last I had a direction to follow.

I  managed to find some scrap KDTO long enough to only need 2 lengths to complete the coaming, at 5mm thick I used 150mm long scarf joints, prepared parts 31mm high for the 2 main layers, planning to stagger the placing of the joints, and also sufficient for 4 layers 13mm high for the double lip. Noting the previous success of the no soak samples steamed for 8 and 10mins I decide that I would go with 10mins for all pieces, so wrote up a detailed run sheet, (I was getting good at that part), set up and started the steamer, set the interval timer for 2mins, allowing time to fiddle with the extra scarf joints, and set out to assured success.

All my main samples failed, on the front bend, not badly but not useable either, but I did manage to bend 4 layers at once of the lip parts, so not complete failure!

Now moving firmly into the 150min soak camp I looked around for some new timber to reduce to scrap and managed to find not only enough KDTO but also some KD American Oak, didn’t know if it was white red or brindle, but decided to also give it a try.

More detailed run sheets later, (I do use reused recycled paper), I planned 24 samples all with 150min soak, and 6 each at 8, 12, 14 and 16mins steam, KDTO, 16 good grain orientation and 4 cross grain, and KDAO, 4 good grain. This time I also checked the moisture content at 1 hour intervals throughout the soak, the KDTO got to 22% at about 90mins and the KDAO was a bit higher at 25-30% by that time, and I noted that it was “very bendy”, even before steamimg. I also prepared some lip samples.

I achieved pretty much perfect results for all situations, except some of the KDTO cross grain samples split along the grain, as you might expect.

However the KDAO, was an absolute joy! Bending just like Brian shows in his videos, so now the search is on for enough scrap pieces to use to build the full coaming.

NOW I’M AN EXPERT IN STEAM BENDING KD TIMBER!, (Well, 6mm THICK anyway!), So… I’M INTO THE REAL THING!

As KDTO is our most common scrap timber I decided to use that as a first try at a full laminated coaming. Laminations as follows:

First trial of scarfing on the table saw – Quickly abandoned as too stressful and changed to using a small block plane

Main body, 31mm x 2x5mm layers, each with 2 parts per circumference with 150mm scarf joints. Joints were planned to land along the “straight” sides but be staggered between layers.

Lip, 13mm x 4×4.5mm layers, again each with 2 parts per circumference as for the main body. (a lot more joints so very difficult to stagger them, adequately). I also planned to bend the 4 layers as one unit, as I had done successfully before, and to glue all the interlayer joints after allowing the parts to cool and “set” overnight.

After some thought and with reference to Brian’s formula for working out the length of the full circumference, I made a stab at the change of length needed for each layer at 6 X the thickness of the layer, and this proved reasonably successful.

Using the 150min soak and 14min steam regime all the bending went to plan with the following challenges.

There was a strong tendency for the layers to separate from the form well before the tangent point of the sharp end curve, so I needed to sort a clamping system to overcome this. This was also exacerbated by any, even minor, variations in the layer grain or thickness.

First KDTO coaming – long steamer tube in background
First KDTO coamimg – all laminates ready for gluing
First KDTO coaming – all 6 lamintes – 2parts per circumference bent and clamped

I needed to clamp and allow to cool and “set” the main body prior to adding the lip layers, so this added an extra day to the process.

It was difficult to keep the 4 lip layers within the same horizontal plane, particularly on the sharp bend where the outer layers wanted to slip and drop lower than the top of the main body. A late thought that may be worth trying for a future build, is to fabricate the coaming upside down, with the lip sitting on the ply.

Once all six layers were cooled and set I removed the clamps and proceeded to glue the 2 main body layers while they were on the form.

The TENNIS RACQUET 🙂 🙁

Next day I removed this from the form and proceeded to glue the 4 lip layers into place. The final coaming looked great, was super strong and I was very happy with the result, until the next day I decided to check that it would still fit on the form. Of course it wouldn’t! It was 30mm too short and 60mm too wide, the main body had been pushed out of shape as I added the lip layers. It is possible that I may be able to repurpose it as a large tennis racquet, some strange harp like instrument, or a weaving frame, but as an F1 coaming it was USELESS!

Fortunately I had also collected sufficient KDAO parts to redo the process, and so, 4 days later I finally had a properly shaped F1 coamimg.

I still see ahead of me the following challenges:

To make a coaming using full length layers to remove the need for inter layer scarf joints, this will require me to purchase or find, full length timber, rather than using scrap.

To make a coamimg using full thickness full length layers, like other grownups do, again using purchased timber. So, being very mindful of Brian’s very wise advice, “You can very quickly chew through a lot of $ in timber costs, trying and failing to use different woods”, and the existing huge pile of failed test samples, there are lots of experiments and tests still to come.

But for now I’m moving onto the adventures of the F1 main build.

below still to be edited and photos added

DECK BUILD.

Following the student blog from Peter of Adelaide, South Australia, who has successfully built and extensively used, a couple of F1s and an F2 for about 5 years, (obviously a blink of the eye compared to Brian’s vast knowledge), I’ve decided to use PAULOWNIA for the long timbers. This is a plantation timber and the major supplier is located just down the coast at Coffs Harbour, so it’s ticking lots of environmental boxes.

Paulownia is approximately 25% lighter than WRC, this is attractive as the aim is to build ultra light, but has a 55% lower Elastic Modulus, not attractive if you want a strong and durable boat. This is where Peter’s experience is giving me extra courage.

It seems to me that there are several aspects to the sizing of timber, the first is the experience of what has worked in the past with timbers that are readily available locally, then there is the comparison of that with the physical properties of any new material that may be being considered, finally say, there is the physical constraints of the construction method. So for instance if you need a 6mm mortises, as in the rib mortises on the bottom of the gunwales, then the reality is that you are going to need your timber to be a minimum of 16-18mm wide, irrespective of how strong the timber is, you need the cheeks of the mortise to have some strength and you need some tolerance to allow for slightly off centre mortising. In reality the actual strength of the timber may only be a very minor consideration in deciding the section measurements of the gunwales, say. It is interesting that there are a significant number of student build blogs that mention the splitting of timber adjacent to the rib mortises during the ribbing process, and Brian also  mentions this and downplays it as a problem.

Early in the process I did ask Brian what was the failure mechanism of the F1 and in particular the ultra light version, (quoted “5,000” miles paddling against “10,000” miles), and got the answer that they don’t really fail. So given that most of my paddling will be flat water with the possible addition of some small surf, that the lower limit of 8000km is, to me, a lot of paddling, coupled with Peter’s 5 years of experience, I’ve decided to ignore the strength difference between Paulownia and WRC and size my timbers accordingly. Ultimately, of course, time will tell.

I decided early in the process that I would need to build two boats to gain from the experience and hopefully learn from my (expected myriad) mistakes, thus I bought enough Paulownia for 2 boats. Talking with the very helpful David Evans at Paulownia Australia, I realized that I would not be able to buy timbers long enough for the F1 without joints, and so with a lot of planning I managed to get 2 boats worth out of 1 x 150x75x3800 (rough sawn turned out to be 158×80, which was very handy). I also ordered 2x200x50x2400 to allow for 2 Greenland paddles per boat.

The roughly 78x80x3800 section was tight but adequate to give me all the long timbers, including extras for the required scarf joints for gunwales, stringers and keel as well as sufficient for the laminated deck beams.

For these cuts I didn’t have access to a narrow kerf table saw so used a band saw, which was mostly successful as I had allowed an extra 1mm in width for final thicknessing. Mostly this proved adequate but not entirely. With a short length of 1 gunwale being slightly under width, (15mm compared to 16mm) see below for the consequences of this.

I used a power planner, purchased from ALDI’s centre isle for $50, to cut the scarf joint tapers, (1/20 so 320mm long), and was happy with the results. All joints have been made using Selleys Durabond Polyurethane glue, a foaming glue similar to Brian’s Gorilla Glue and were wrapped in plastic and splinted and clamped on all faces, then finally hand planned to final thickness.

Using Brian’s “sag” test both gunwales appeared to be similar despite the slight thickness differential, (as noted above, but not really picked up until the deck beams were installed), however because the timber is so light I think I should have added some weights to the mid span to exaggerate and pick up the differences. Never the less I proceeded to lay out the deck beams and rib mortices. As I intended to complete the build in metric I had set up and used an Excel sheet to both convert the plan “ measurements and to adjust these for the ultra light and my weight version.

As I am only 58kg, don’t intend to do long camping trips and was looking for ultra light, I originally planned to go with the 100-125# version but on further discussion with Brian and again checking the “fine print” in the plans I decided to go to the mid 125-150# (57-68kg) version.

So with gunwales nicely marked out as per my Excel sheet I proceeded to cut all the deck and rib mortises without any problems.

The next job was to fabricate the laminated deck beams, using the “scraps” from the long section timber.

DECK BEAMS

In the interests of “play”, to take the weight savings to the extreme and use up more time, (remember I’m retired and have plenty), I decided to explore the possibility of creating an “I” section that would be lighter but also stronger than the 21×45 standard. By judiciously using the offcuts that I had I settled on a section made up of 2 outer laminates 38×4, and 4 inners 27×4, which was 28% lighter and yet just slightly stiffer, again ignoring the differences in stiffness between WRC and Paulownia.

Naturally this required a few other adjustments.

  • In the laminating process I needed to ensure that the central 27 wide parts were centralized, I used small packing blocks for this.
  • In cutting the end tenons I need to locate them centrally rather than to one edge as is standard, this naturally slightly displaces each beam, but not significantly. I also needed to adjust the width of the gauge stick, used for laying out the tenon to allow the new 24 high beam to still sit below the top of the gunwale.
  • For DB#3, that carries the foredeck stringer, (in a small rebate), and the front of the cockpit coaming I changed the top, 27 wide, laminate of the central  4 with one 45 wide, giving extra strength and more width to seat the stringer and coaming.

The process worked well for both curved and flat beams, the only change was that for DB#4 at the back of the cockpit I used some of my old friend KDTO for the 2 outer laminates, and because I was scrounging for timber at this stage allowed 2 x 50mm gaps at about 100mm from each end in the central layers, see photo.

CHECKING FOR SYMMETRY

After a very ordinary attempt to scarf the ends of the gunwales to fit the bow and stern stems, I decided to check the symmetry.

Shock horror! Big eye view it looked ok, (I must have lousy eyes!), but there were a lot of visual distractions around so decided to pull a string and measure it. Brian’s limit was, I think, less than 3mm. I was pushing that for DB#1-3, but DB#4 & 5 were 10 to 15mm off! Yikes! Time to get serious.

First I went back to the scarfs, pulling the deck apart and using a jack plane and file to shape both sides to symmetrical pencil lines. Re-assembled, the problems were marginally reduced. Next I tried Brian’s suggestion of sliding the gunwales lengthwise and although this improved the stern situation it worsened the alignment at the bow.

The most troubling concern was that I still did not know the cause of the problem, was it inherent in differences in the timber? As they were adjacent cuts from the same section, this seemed unlikely, but what else?

Again I pulled the deck apart and re did the sag test, this time noticing that the major difference, which was only about 6mm, was in the same area as DB#4 & 5. Careful inspection revealed that, over a length of about 1m, the starboard gunwale was about 1mm thinner than the port. Momentarily I contemplated laminating a strip onto this section. Eventually, I fastened on Brian’s suggestion to not get too desperate at this point as the future processes tended to bring the build back into symmetry. I also reminded myself that I had timber for another boat, and it was all a learning experience.  So proceeded to peg and lash the ends. As per Brian’s instructions the lashing holes were drilled just forward of the Capture Forms. (More on this later)

At this point, with some shape in the mess of timber parts, other Men’s Shed members were starting to show more interest.

RIB BENDING

Having discovered sufficient scrap American Oak, (presumed white but maybe not), certainly kiln dried, and having also pretty much solved the problem of bending this timber, I resolved to use it for the majority of the ribs, except for 1-3 or 4. I had previously purchased a “30 serving” of the best green white oak from Brian so planned to use this as needed and for the tight V bends in the bow.

I started from rib#4 and moved backwards, and apart from a couple of very obviously inferior pieces which broke managed to bend all the ribs through to the stern pretty successfully, using a 150min soak and 14-16 minute steam. Several were a bit “lumpy” due to poor grain so I replaced them.

I also realised that Brian’s notes re the hand positioning of the “square” bent ribs, (from the cockpit back), starting with the ends of the rib just inside the outer edge of the palm, only really applied if your hands were the same size as Brian’s, mine are significantly smaller and so my first bends in this area tended to be shallower, wider and did not line up well with the gunwales. Eventually I re bent most of these also and was pretty happy with the final result.

Despite Brian’s beautiful timber and probably because I was over sensitive to his admonition to bevery wary of over steaming, my first attempts at bending Ribs 1-3, at 4 minutes steam, were a failure. Eventually I used the short off cuts from these ribs to do a steaming time test, settling on a 7-8 minutes and was rewarded with success. Next time I’ll use the off cuts and do the testing first.

All the above happened over several days including a weekend, so to ensure that things stayed in shape I clamped the keel in place to every rib at the end of each session.

The kayak is now looking like a kayak, and Men’s Shed interest is increasing exponentially. There is a small group of Sheders who are already kayakers, and interestingly they were the most standoffish and sceptical at the start of the project, but are now starting to show more interest.

KEEL, STEMS & STRINGERS

Like the gunwales the keel & stringers were scarf jointed to length, I had originally planned to place all the joints towards the stern assuming that there would be less stress there. I persisted with this for the gunwales and keel but placed the stringer scarfs at the bow because of the extra bending required to force them higher in the stern to give the best surf and tracking performance. This has worked well, with all my scarfs at better than 1:20.

Because of the available size of timber both the stems were also laminated.

With plenty of measuring and some pushing of rib shape to work on overcoming the lack of symmetry, the lashing of the keel went well, and true to Brian’s prediction the shape is becoming more symmetrical as it proceeds. With the stringers, as well as the height checks given in the plans I measured diagonally from the opposite gunwale and again with judicious pushing and pulling managed to get them lashed and looking and measuring ok. I did need to tie off and re do the lashings to the last 3 ribs on both sides but am happy with the result. The skin clearance throughout the boat is good except for R#19 port side, but I have managed to push the stringer up a bit and now have 3mm clear.

I encountered a problem when I came to lash the stringers up to the gunwale at the stern.  As above, I had originally lashed the gunwales together just in front of the capture form. However I now found that this was approximately 100mm inboard from where i needed to lash the stringers, just behind the stern stem. On reflection this error was caused by my early decision to reduce the size of the gunwales and reference their position relative to their bottom edge but place the standard sized capture form on the top of the gunwales. This mismatch in sizes meant that the capture form was moved much further inboard, (an extension of the butterfly/hurricane nexus). After much head scratching and soul searching I drilled a new hole through the gunwales directly above the cross of stringer and rear of the stem, and lashed away, problem solved.

SYMMETRY RE VISITED

With the structure of the kayak completed I’m happy with the visual shape, straightness of the keel and quite amazingly with the ultimate trueness of the stringline test along the deck beams, not perfect but very adequate.

I was recently absent due to a Covid scare on a day, early July 2022, when the Shed kayak group mostly attend. This allowed time for that group to inspect the project without me hovering. All reports at my next attendance were VERY rosy. Great shape! Well executed! Although I know that the latter is not quite right it is gratifying.

MODIFICATIONS

Noting that I have the timber to build another kayak, I’m looking as this version, F1.1, as a temporary own, a toe in the water that may eventually be sold or given away, thus I have decided that I need to make as many modifications as possible so that it appeals to, or fits, the largest number of people.

I increased the size to mid 125-150#, although I’m just over 125#, am unlikely to be carrying much camping gear, and I’ve pushed the stubby and ultralite versions as much as possible.

I’ve modified the stern stem to take a possible future rudder.

I’ve added “GoPro” mounting blocks to both gunwales rather than my hand preferred RH only.

And I’m adding bulkheads and hatches to both front and rear.

BULKHEADS & HATCHES

The inclusion of bulkheads and hatches will probably preclude any modifications for adding a sail but I may revisit that at a later date or in F1.2.

I was first inspired to pursue this option by Peter from Adelaide and his F2 conversion, and also the prohibitive cost of buying custom float bags.

So having made the decision I needed to sort out the execution. There were lots of questions. What to use for the bulkheads and how to seal them to the frame and skin, whether to use readymade hatches or make them completely myself, what size could they be and how could they be supported and sealed to the skin.

First the bulkheads. Guru Peter had used closed (or mini) cell foam as his bulkhead material and sealed it to the frame and skin, using a SikaFlex product, during the skinning process, so I decided that was the way to go, easy peasy!. Obviously the bulkheads need to be sealed to both the frame, (keel, stringers and gunwales), and to the skin, so the first job was to cut the material to fit the final shape at the locations chosen. The bow bulkhead was located just behind DB#2 and the rear just behind DB#4.

I started by making a cardboard template including cut outs for the keel and stringers and realised that it would be too difficult to fit the final product so decide that I would make individual pieces for the spaces between the keel and stringers and the main and secondary stringers. then use a single large piece to fit inside. The closed cell foam that I had was 25mm thick, reasonably stiff and could be joined using contact adhesive. So having shaped all the parts I fixed the outer infills and then used contact adhesive to fix the inner portion to the inside surfaces of outer infils and the keel, stringers and gunwales. I also fixed small triangular infills in the space above the secondary stringer.

The advice that I had and followed, was that the outer face of the bulkhead should be proud of the skin line by about 3mm. In retrospect I would make them flush with the skin line and fix everything using a sealant such as Selleys SolarFlex, which I later used to seal the KS hatch surrounds to the skin and top inner lip

Now for the hatches. One of my Men’s Shed paddling mates had shown me his sit on kayak that had a big oval hatch on the back deck.

I still had not finalized what the hatches were to be made of, nor how they were going to be incorporated into the kayak, but after lots of thought and many sketches I came up with a hybrid method, my own supporting base and lip, similar to a very thin coaming, and a KS hatch and surround outer, or similar. This would allow me to seal the skin to the structure during the stitching and coating processes and to then seal the KS ABS plastic hatch surround to the skin in a later step.

I eventually found a hatch the same as my mate’s, (KayakSports 42/30 Oval) on the internet, and thought I could just squeeze that into the space between the gunwales and DB#1 and DB#2 on the front deck. However when the hatch arrived it was immediately obvious that it was just too big for the space available and I then changed to using KS Round 24 hatches and surrounds for both the front and rear.

There was still a lot of work sorting out the line of the forward deck stringer, which was of course interrupted by the forward hatch, but I eventually came up with what I thought was a good solution for strength, aesthetics and how the cloth would “flow” around the hatch. This split the forward deck stringer into 2 parts, with the upper surface as a straight line from DB#3 to the bow, and the height of the hatch a compromise between being low to suit the gunwales, high to suit the stringer line and flow of skin over the DBs and around it all.

Bow to DB#1 required the detailed shaping of the stringer to fit neatly down between the gunwales with about 15mm sitting proud, and be fixed  here with a fairly standard V2Y lashing. The rear end overlapped DB#1 by about 30mm to allow it to be lashed to the beam and extend the skin line onto the hatch base.

DB#2 to DB#3 was pretty standard with a minor rebate in the latter and an overhang at the former of about 80mm, again to allow lashing and to extend the skin line to the hatch base.

The sewing holes, predrilled in the hatch base, at about 30mm spacings, were placed along a curved line about 20mm outside the outer edge of the KS ABS surround and at the front and rear lined up with the top sloped shape of the deck stringer ends.

Very early in the planning stage I had made the decision to use Corey’s “7oz” cloth to assist with the Ultralite aim, and I now belatedly learned that I would need to keep this wet from the initial lacing right through to the final stitch, a serious lack of early research on my part!, although in my ignorance at that time I’d probably have missed the ramifications.

This had two major consequences, the first was that any sealant that I planned to use to seal the bulkheads to the skin would need to adhere to wet cloth and have a relatively long set time. Secondly, once I started the final lacing stretch of the cloth I would need to keep it wet and cool and complete the whole sewing operation. On top of Brian’s estimate of 4 to 6 hours to complete the sewing I would need to add extra time for the final lacing stretch, and the extra stretching and sewing needed to fix the cloth to the hatch bases and the top inner lips, my first estimate was that I would need to allow an extra hour for each hatch.

SKINNING

A couple of days before the planned stitching day I used a scrap of cloth, about 100mm wide, wrapped around the middle of the kayak for a stitching practice. This gave me the first shock! In Brian’s videos there didn’t appear to be much effort to pierce the cloth with the needle, and the stitching process flowed along quite quickly. With this sample I could barely get the needle to penetrate one thickness, so my visions and plans of a relatively relaxed  6 hour sewing session became a potential nightmare and were immediately doubled.

The next “practice” job was sewing up the stems, starting at the stern, as Brian suggested, so that the early potential wabbles would not be so much in my face. As above, I was giving myself as many options as I could and had made allowance on the stern for the possible latter addition of a rudder, so I got the extra practice of stitching both in the centre and to the side of the stem. Given the difficulties of needle penetration this first real sew turned out not too bad, and only took a bit over 30 minutes or about 1 ½ hours per meter!

Another early decision that I had made, without much thought, was to use the same dark brown thread for both the lacing and the sewing. I was planning to use a “red” colouring for the coating and thought that this thread colour would fit in better than white, assuming that the thread would not take the colour as much as the cloth. Against the white cloth it certainly stood out, and meant that there was no possibility of hiding any crooked stitch lines. As it finally turned out I’m pretty happy with the result as the contrasting stitch colour looks like a deliberate feature and part of the “honesty” of the finish.

Having completed the stern seam, I needed to complete that in the bow after estimating the potential stretch of the cloth. After some trial and error I eventually opted for 60mm, and completed the bow seam, again this was slow but the straightness had improved. To fit the cloth along the keel line I fitted the stern “cup”, set the kayak up on saw horses, got a men’s shed mate to hold the stern, and as per Brian’s suggestion lay on the floor at the bow and pulled the bow “cup” out and down, and pulled out and down and pulled out and down! All while my mate was vainly trying to hold the stern in position. There was no way that this cloth was going to stretch and fit, and I was fearful of breaking the gunwales over the saw horses and the hull folding in half. So borrowing a page out of “Don’s disaster handbook” I immediately imagined some solutions, such as cutting the cloth across the centre and sewing in an extra length, or cutting back the stems to make the kayak shorter.

Fortunately I first decided to sleep on the problem. As a result decided that I would strap the stern down to a bench vice, get rid of the mate and sawhorses and rely on only my knees as the support for the gunwales. So, back on my back, knees in place, gripping the bow cup as hard as I could I jerked out and down and the cup slipped nicely into place!, but with alarmingly big longitudinal stretch waves at both bow and stern. I tentatively tried to pull these out by pulling the cloth tightly over the foredeck stringer, with some, but not enough success. Brian’s advice was that these were normal and could be pulled out in the final lacing.

Having completed the preliminary lacing with the cloth dry, I now planned the BIG day. On Brian’s advice, once I started the final lacing I would need to keep the cloth wet and complete the full sew up in one session. With the specific complications of the cloth being harder to penetrate and sew, fixing and sealing the 2 bulkheads in place and the inclusion of the 2 hatch surrounds, I expected the operation to blow out from Brian’s estimate of about 4 hours to about 10.

To ensure that the bulk of the sewing could be completed in the coolest part of the day I planned to start early and signed into the shed at 3am, also, as I needed to keep the cloth wet through the operation I would do it outside. Fortunately the Men’s Shed had both water and light adjacent to the area where i would be working, however I also bought a good LED head torch so that I wasn’t trying to work in the shadow of my head.

Keeping the cloth wet with a hose and garden sprinkler, I started with the final lacing, working firstly between the stern and the back of the aft hatch, and the bow and front of the fore hatch, pulling as hard as I could but could not really fully remove the longitudinal waves in the cloth caused by the keel stretching, (the cloth was tight but not drum tight). Once I moved into the areas between both hatches and the cockpit, I also need to seal the bulkheads to the cloth. The bulkheads are black closed cell foam, 25mm thick, and I had “foolishly” bought white sealant, so this would later stick out like the proverbial sore thumb.

I decided to work on the sections below the gunwales first so with the kayak tipped upside down, I propped the partly laced and stretched cloth away from the bulkhead,  applied 2 beads of sealant, one close to each edge of the bulkhead, and then let the cloth come back in contact with the sealant, turned the kayak back right side up and completed the final tight lacing. The sealant was suitable for adhering to wet surfaces and had a set time of about 30 minutes so I did the stern first, then the bow. I hoped that this would allow the sealant to set to the cloth below the gunwales, and then, without disturbing the below gunwale seal, I could partly loosen the lacing and using a similar process, complete the sealing of the bulkheads to the deck cloth. This seemed to work pretty well at the time. By now we were well into daylight and heat and I moved the whole process, about 15m, to the deep shade of a nearby tree.

And so I proceeded with the stitching, working stern to rear hatch, bow to front hatch, stern hatch to cockpit and bow hatch to cockpit. Unfortunately, probably due to the geometry of the cloth around the front hatch and the proximity of the front bullhead to DB#2, the final tight lacing in this area was skewed out of position and as I sewed the seam the cloth was pulled into a completely different position away from the original sealant lines. What a mess! But, due to the need to complete the whole stitching in one session I just needed to continue.

By this stage I had been going for about 7 hours, and I had decide to complete the sewing around the hatches and cockpit in the following order, preliminary sewing of the cloth to both hatch bases stretching it into place as much as possible, main cockpit fix and sew, and finally sewing the cloth to the hatch up stands. The preliminary sewing of the cloth to each hatch base took about 1 hour, so I had been working continuously for about 9 hours before I started on fixing the cockpit.

As per the instructions I strapped it down, (probably not tight enough), checked its  lateral position and started sewing, by the time I got to the front, having completed one side I realized that the whole cockpit was positioned too far forward and was too tight to the end of the front deck stringer, (obviously I was getting tired and making “unforced” errors). By judicious pushing and shoving I managed to push it back enough to get the required “pinky” between the cockpit lip and the stringer, in the process probably loosening the hold down strap, and completed the full sewing.

Fortunately, I had no problems with the sewing in of the 2 hatch up stands, and was happy with the look and feel of these areas.

Finally I was done, and was happy that I planned to colour the kayak red as there were many patches of blood, from needle pierced fingers and also towards the end just my finger skin worn away.

When you start a project like this you have an end vision of perfection, mine had received a bad battering this day.

GOOPING AND COLOURING

Very early in the process I had considered colour, and decided that I would like to get a translucent warm red. Some years ago i had lived in Broome on the far north west coast of Western Australia, which is noted for its pindan soils, and this “outback” red is what I wanted to achieve. At this point in the process i was seriously trying to save money and eventually I found a seller in Sri Lanka who could supply small amounts of oxide colour powder very cheaply, so I bought a red and yellow and stored them away.

I had also bought 1 ½ serves of Corey’s goop, after being unable to find anything else locally that appeared suitable, especially that would remain flexible throughout its life.

So having (almost) recovered from the trauma of the skin sewing I planned the gooping with a vision of a perfectly smooth, translucent warm red coating, that would look fabulous and show the “frame structure” underneath.

Because I didn’t have any suitable measures I had bought a few 60ml syringes, and planned to use one for A and one for B, I also labled stiring sticks A and B and “mixed”. As per instructions I mixed my red and yellow Sri Lankan oxides, in what I thought would be the right mix and added them to a small amount of A goop. Then, next morning, using the syringes, mixed a very small batch and applied it to a scrap of material. The colour seemed good and the goop set in the appropriate time so I was ready to go.

It was a bit over a week since I had completed the skinning, and the kayak had been sitting in the dusty Mens Shed for all that time, so I took my time and used the compressed air gun to blow it off and clean it up really well, then mixed up the first batch of goop for the ½ base. I poured and rolled it on and proceeded to the other half of the base, and then noticed that the whole area was covered in small clearer patches as the goop was “pulling back” from “contaminated” areas. I could best describe the look as the “rain drop” effect, as if the surface had been splattered with rain drops, There was a clear inner spot about 3mm across and then a darker ring about 2mm wide where the excess material accumulated.

I was happy with the apparent penetration of the goop into the weave of the cloth, even in the clear spots, but it was obvious that the coating thickness in these area was much reduced, so I attempted to scrub them to allow the coating come back into the “bare” areas, this was partly successful at first but then the goop crept back away again. Conscious of the time constraints on completion of the coating I decided to proceed with the remaining coats, and hoped that the subsequent ones would cover over the “bare” spots. This did not happen to any significant degree and the spots were thus permanent.

The same problem manifested itself on the deck, so having effectively completed the gooping, I went home very dejected, I had done 3 coats to the base and two to the deck, using all the single serve of goop, and the very last of the goop with the oxide mixed in, and although it looked horrible I was convinced that it would be waterproof.

Overnight, I listed the possible causes, that the original cloth was contaminated, (unlikely because of all the water that I had used during the stitching process), that the compressed air had not removed all the dust, that someone has sprayed some paint in the shed and some had got on the cloth, that the compressed air had sprayed some oil on to the cloth, and finally that the oxide was contaminated. I still believed that even in the clear centre of the spots that the cloth had been fully wetted and that the result would be waterproof.

 As insurance, decided that I would add a further coat to both base and deck in an effort to ensure that it really was waterproof. When I returned and looked closely I noticed that as well as the “rain spots”, there were also some very small bumps. When I scratched these it was obvious that they included a lump of oxide, in using the very last of the oxide mix I had scraped the bottom of the container and there must have been some oxide that had not mix properly. So the purpose of the next coat was to ensure that I had at least one coat that covered both the “rain spots” and the oxide bumps. To eliminate as many of the causes as possible I used a clear coating and painstakingly lightly sanded all the “rain spots”.  This coat appeared to stick to the “rain spot” centers and also to properly cover the small oxide bumps, so finally I was done.

Probably the ugliest goop job in history, but hopefully it would be waterproof, long lived, and just possibly the “rain spots” would enhance the performance, like the bumps on high performance shark skin Olympic swimming costumes! J

Amazingly the Mens Shed members, thought it looked great, ( I did stop them getting too close), and were keen to take part in the launching ceremony. That was NOT going to happen, so I loaded it, (Her? They?), onto the new roof racks and took it home, where Jan insisted that before putting it in the local lake where it might sink that we had to try in the pool. I thought “She” would feel ashamed to be first floated in such a constrained place, but she took it in her stride, and the next day I wheeled her, on the home made trolly, the 500m to the local lake launching place. With Jan watching and attempting to video the procedure, “she” was launched, I managed to get in without tipping out, and I, (we), paddled off for the first of what will, I hope, be many adventures.

PROOF’S IN THE PUDDING

So what is the result?

Brian emailed a set of F1 plans, 02/13/22.

Wet her bottom in the pool, 10/07/22.

So total time including gathering extra courage, materials and completing the build, about 8 months. Certainly one of the slowest, and possibly one of the ugliest finishes, but she only weighs 13.5kg, (just under 30lb), fully fitted out with bulkheads and hatches, camping mat seat and manual bilge pump, full deck lines and 2 Greenland paddles. I like the colour even though it is a bit more opaque that I had imagined, and I’ve stopped obsessing about the “rain spot” finish.

In the just over 3 months since she was launched, we’ve paddled almost 240km, mostly on the local still water lake, but with 2 excursions to the surf mouth of the Tallebudgera Creek, just down the coast, and “caught” a few waves each time, even I, as a VERY novice paddler, can feel her come alive in the waves . She is very stable and the only time I’ve tipped out was when trying to launch off some rough rocks and my foot slipped.

The hatches are very waterproof and their supports feel strong, although the front one does make stowing the spare paddle under the bow strap impossible, but as the deck line crosses just in front of this hatch I use that instead. The bulkheads are mostly waterproof but with the cockpit full some water does leak through, not enough to compromise the float chambers, but enough that you notice when it’s time to clean up.

When I first started to paddle I thought that she pulled slightly to the port side, and I presumed that this was probably due to the problems I had with an out of symmetry frame. However I’m now sure that was as a result of my out of balance paddling technique, now straight line paddling, even in fairly windy conditions is pretty easy. The Australian Institute of Sport, AIS, canoe/kayak group train on the local lake so I’m often overtaken by those “eye candy” elite paddlers, but mostly I finish my paddle, sometimes up to 16km at an average speed just over 7km/hr, so at the moment I’m pretty happy with that. As mentioned I have 2 Greenland paddles, and they are the things that provoke the most comment from other paddlers, who are surprised at the speed that we get along. Even though, I’m a completely VIRGIN paddler I’ve never pulled up sore from even my longest paddle.

So… the big question? Am I happy with the year’s effort and result, and would I do it again? As part of my initial purchases I bought enough long timber, Paulownia, to make 2 frames, and of the 30 beautiful rib bending timber I bought from Brian, I only used 5. I have now taught myself to bend 10mm thick kiln dried American oak for use in the coaming, so, despite the fact that there would need to be plenty of improvements, the answer to both those questions is a resounding YES!

Cheers, Don McMahon, 77yo virgin kayak builder and paddler, Lower Gold Coast, QLD, Australia.

Don

View posts by Don
Early 2022. I'm a long retired civil/structural engineer/project manager, and now living on the Gold Coast, QLD, Australia. I've been a member of the Burleigh men's shed for 8 years, so have easy access to an array of woodworking tools and workshop space, (as long as I don't spread out too much, which may be difficult!) I'm completely new to kayaking, previously I've paddled and steered Dragon boats at Australian national level, but covid put a stop to that. Late last year as I looked for a new upper body fitness option, I explored buying and using an inflatable kayak, to avoid the presumed hassle of loading a heavy kayak on the car. Serendipitously over xmas I discovered the Cape Falco Kayaks site and after listening to Brian's talk on the development and adaptability of the SoF F1decided to make this build my 2022 mens shed project. As an extra project I'll need to build a bike trailer to be able to tow the F1 to the local lakes and creeks. So here we are about to start, but a little past the actual beginning.

1 Comment

  1. mark
    December 30, 2022

    Don, as a fellow Aussie – just on the other side of the ‘island’ – I’m interested in your experiments with using Aussie timbers. Someone in Queensland managed to team bend bamboo ribs for an F1 build. Nearly got me started on one myself… Maybe I should look out for straight grain American oak in Perth.

    What timber are you using for your stringers (or whatever the long ‘bits’ are called)?

    Looking forward to your updates. If you ge the chance to post some photos, that would be great.

    Reply

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