The lessons learned are not necessarily in any order which means you have to read the lot. :-)
1. It does not take a genius to build a kayak. I am living proof. I have never, before now, built a boat of any sort. Nor did I start with any tools except an electric drill. Had to buy a few things though. Will cover that later.
2. It helps to have been a draughtsman, in a previous life. Or at least be able to interpret drawings and an offset table. If you but plans you may be lucky enough to get them with the profiles drawn to a 1:1 scale. If not then you will have to draw the profiles yourself from measurements on the offset table. This is not hard but if you are unsure then ask someone who has done it before.
3. If possible, find someone who has done it before. It is good to have someone to call to ask about terminology. I made a couple of clangers because I had just no idea what I didn't know.
4. Find out how to use a Strongback. I didn't. While it all seems obvious to me now, it wasn't when I started. Bolt the profiles to the strongback to give you a firm base from which to lay the gunwales and chines. Best would be to find someone in the process of building and have a look at how they use the strongback. BTW. I built mine from two 200x50 plywood beams. Consequently it is strong and very straight and will not go out of alignment. Keep your strongback if at all possible. You WILL built another kayak and you will therefore use it again.
5. Duct take has it's uses but holding profiles in place on the strongback is not one of them. DOH. :-)
6. Except for placing the gunwales, I built the rest of the kayak without help. That is not to say you should not have help... but it can be done.
7. It is best to build indoors ie a garage. However if you do not have one then build it outside. :-) I did.
8. Pine is fine for keelson, gunwales, chines and stringers. Perhaps Ceder would be lighter and less likely to rot if the kayak was subject to long periods in the weather.
8a. Use 19mm ply (7 ply) for the profiles. This is a little thicker that some folks recommend but gives much better surface area for the chines, and requires slightly less accuracy for drilling (see 10b.)
9. Check out the price of Ceder anyway. It may not be that expensive, compared to pine. However it is hard to get any Ceder over 4.8m long (unless perhaps you live in Auckland or the US).
10. I used Gorilla Glue to glue up the chines etc to the profiles. I also screwed every joint just in case the glue fails. Although "water proof" some of the more experienced blokes suggest it is, at best, water resistant and will break down in time. Having said that, Gorilla Glue was easy to administer. I used one tube for the kayak.
10a. Screw each joint. it holds the joint in place while the glue sews and adds extra strength to the joint.
10b. Drill each hole that you screw. Drill about 3/4 the depth of the screw including into the plywood profile. If you don't then you may fine the plywood splits a little.
11. Put the cap on the Gorilla Glue when not in use, even between each squirt. I found that out, about 2/3 ways through the tube. :-) Once I got into the cap putting on practice I found that the glue was very easy to use even after days of non use.
12. It was suggested, and I did, coat all the Gorilla Glue joints with epoxy resin. This waterproofed the joints.
13. I used a product called "CD50" as a timber preservative on the pine. There was some concern that this would stain the polyester fabric. It did, in places. This would be a problem if you want to keep the fabric white, even after urethane coating (which might yellow it anyway). I was going for a tan colour and the staining did not show through, after a couple of coats of urethane. I am not sure about the worth of the CD50 but felt better for having applied it anyway.
14. Use a jigsaw to cut the profiles. However cut accuracy is useful to ensure a tight but comfortable fit of the chines and stringers. However you might get a better result using a tenon saw and chisel to cut out the chine notches in the profiles.
15. Learn how to cut the gunwales so that they join nicely to the keelson at the bow (there is a name for this type of joint... which I have forgotten). I made a real mess of it. Nothing that could not be fixed with glue and screws and hidden under the skin but.... ugh... it was ugly.
16. Add what you want to add on the inside of your kayak, before you skin it. It is a lot easier that way. Some suggestions include, flotation devices, foot pedals, seating, internal decking for seating and storage areas.
16a. Add floatation devices before skinning unless you intend to only use air bags. I used Polystyrene blocks. There is some suggestion that they are not a good long term solution but I am OK with them so far. Other alternatives include:
- Closed cell rubber, especially if you can get a lot, cheap.
- Empty wine bladders from 3 litre chateau le cardboard.
- Empty 2 litre plastic Coke (or any brand you like) bottles.
- Airbags (you can buy these).
The point is this. The main purpose of the floatation device is to exclude water from the kayak should you turn it upside down. If you exclude water then it become hard to sink. The secondary purpose is to have some part of the kayak stay on the surface, should the craft break up at sea (say you got run over by a British nuclear powered submarine.)
17. If you do add fittings on the inside, think about how you might get them out again (or replace them) after the skin is on. Your only access will be through the cockpit.
18. I used 8.5 oz Ripstop Polyester which came in a 1.9 metre wide bolt, purchased from Hollingsworth Agencies Ltd in Auckland (09 835 2910). However the Baidarka (well... my version of it anyway) is 1.3m circumference, at the widest point. This means you can use a 1.5m wide fabric which opens up your options considerably, particularly if you want to use nylon instead of polyester. I also talk to Tony from Haralds in Christchurch. He is a wind surfer etc who knows his fabrics. You can talk to him on 03 338 7700.
It is a very demonstration, which I followed, about how to skin the kayak. He used nylon but other than that, it is applicable.
Also have a look at this http://nz.youtube.com/watch?v=gYyvIExWkqU&feature=related I am not sure but this looks like a nylon skin with a 2 pot finish over the top.
20. I used a Hi Build sanding sealer as the first coat on the Polyester cuz someone said I should. I think it was a good move as fabric sealer. However I also think you could substitute for just another coat of polyurethane.
21. Sew on the coaming before coating the fabric. This may sound like a no brainer but I tried to do it the other way and it was a disaster. My idea was to get a good sealer coat on the polyester prior to it getting hidden behind the coaming. But, once coated, the polyester became very hard to work with. Better to sew the whole caboodle up and slap a lot of polyester around the fabric from the inside.
22. Support the coaming halfway along it's side. The reason is that you push on the side of the coaming during both entry and exit and extra support means you are less likely to break or crack the coaming. I made a little wooden bracket for this purpose.
23. Build the coaming so as to fit a 'standard' sized spray skirt. Your call but it does make the kayak a little more interchangeable.
24. Make the coaming big enough to get in and out of. The Inuit were not big people, some of us are. :-). If you are upside down under water and unable to roll up then ease of exit is essential.
25. Allow time for the polyurethane to dry between coats. "DOH" you say. But the kayak is quick to coat and you just feel like putting a couple on each day. Best to have a coffee instead and wait.
26. The polyurethane (well, mine anyway) did not come out glassy smooth. It has a very slight bobbly texture time there was a smattering of fine sand in the coating. Don't worry, it still goes like a rocket. However, I think in time, a new coat will come out smoother. Perhaps a light sand between coats may help. I did not try.
27. The design does lend itself to adding a rudder as a clip on to the stern, with wire guides running up the rear deck and through the coaming to foot peddles. I have not done this.
28. As an alternative you could clip on a temporary skeg simply with a elastic strap and a decent hunk of Velcro.
29. Or you could just epoxy on a skeg once you had finished the polyurethane coatings.
30. Either way, the kayak could do with a skeg when in windy conditions or running with the sea.
31. Learn to paddle. This may seem a little obvious but my technique was... lousy and I have paid for that with a bout of tendinitis in my left wrist. Paddling, if seems is not a matter of brute force and tight grip. No. It is all about body movement, using your torso to provide strength and holding the paddle like you would a tea cup. Toodle pip and all that.
32. Fall out. I did. The kayak, with the buoyancy I added as mentioned in 16a, stayed on the surface and when I righted it there was only about 25mm water in the bottom. A few heaves on the pump and it was free of water.
33. Add a wear strip to the keelson and first chines. This could be:
- a thin strip of epoxy, perhaps with glass fibre..
- a thin strip of timber epoxied on.
- A few more coats of polyurethane.
- PVC electrical tape.
Either way, you will feel a lot more comfortable running the kayak up the beach when surfing in, if the fabric over the keelson is protected.
34. You need to add deck lines, even if just for holding your spear paddle. Best to sew in fixtures for holding the lines, before starting the coating process. I think it would be possible to even add water proof recessed fittings made from 32mm drainage pipe caps. I did not do so thinking that I could glue the on later. Gluing sort of works but in the end I think only an epoxy will be strong and waterproof enough.
35. Just enjoy this kayak. It is a thing of beauty and fun. There is huge pleasure in building it. Even more paddling among the hoards of plastic fantastics. They sure look cute but they are not made with your blood, sweet and tears.
36. And don't worry about perfection. Worry about that in your next build. These kayaks will last 10, perhaps 15 years. That's enough. :-) So don't get too frantic.
37. Lastly (perhaps) this has been a great project, with a great outcome, for a fraction of the cost of a new plastic thing and still half the cost of the second hand plastic tub. And it floats... and floats very well.
Take care.
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