First boat: chine fill question

Greetings and thank you!
I've been lurking around reading and learning very much. First post...
So on my first build
(plans here:http://spirainternational.com/HuntingtonHarborPlans.pdf). Framing is done, but now I need to fair it (do I have the language correct?). The chines are cut into and parallel to the frames, though maybe not perfectly flush. Here's a photo:
As the chine goes from the frame to the stem, it can't be bent in only one direction to arrive at the end of the stem. If I bend the chine in only one direction (in the weak direction) then the chine misses the stem totally by about 1.5 inches. So I must bend it in two to have it sit at the stem as the plans show. However, the chine now is not flush to the line of the plywood skin: here's the pic (please correct my language so I may communicate clearly with you): .
It gets worse near the stem: .
What did I do? Is this to be expected? I have searched this forum and believe now I must fill this gap: is this correct?
Thanks for your time and attention. I do appreciate it much. (Having previewed this, I see the photos are rotated 90 degrees. How do I fix this?.)

 

The usual solution is to bevel the chines with a plane so that the bottom face is parallel with the frames. The beveled chine is shown on the second page of the planes. See the attached image which is from the plans. This is done after the chines are bent into position and is much easier if the plane blade is sharp. As the chine is beveled the angle is checked with a board across both chines.

 

I already did that.

The photos are misleading being rotated 90 degrees. The long metal ruler is nearly vertical, and the long faces of the chines are supposed to be creating a uniform plane to attach the ply to. But they are twisted (rolled?) and now present only a small corner to attach the ply to, unless I do something to create a uniform surface across the two chines.

 

DC has urged you to use a sharp plane. A very sharp plane is a pleasure to use whereas a dull one is like a trip through hell. You may need to sharpen it several times while fairing those chine logs. Take you time and do the planeing and the sharpening carefully. Sharp is a subjective term but for good results,sharp means razor sharp.This is one of the more labor intensive and critical parts of the construction process.

By the way, when you are planing, the wood may tend to splinter or exibit rough cuts even with your razor sharp plane.. If that is the case then approach from the opposite end of the boat and plane in the other direction. The direction, relative to the wood grain, that you are planing, makes a big difference in the result.

I am surprised that the plans call for a chine log that is 1/2 x 2. The two inch dimension is much more than necessary and it makes the edge set (bend against the 2 inch direction) unneccessarily difficult. I will not advise you to vary from the plans but I will say that a 2 inch board is 2.3 times stiffer than a 1.5 inch board and 8 times stiffer than a one inch board. Hint; a 3/4 x 1 chine log and inwale strip is sufficient. The skin is what makes the boat stiff, the stringers only provide a simple way to join the individual skin components..

The boat is going to be heavy by kayak standards. But this one is simple and strong, and should be more stable than round chined ones. It is also pretty wide for a kayak. It will behave a bit differntly than one of those rotary molded plastic wonders.

If you are an experienced paddler you may prefer to build the paddle as shown on the plans. It is a feathering style paddle with the blades at right angles to one another. If you are new to paddling then having both blades in the same plane is more practical. The feathering paddle is perhaps worth the trouble when in a headwind. Aside from that there is little reason to feather. The paddle in the plans is a little bit longer than ordinary paddles..The reason for the excessive length is that the boat is wide and the sides are deeper than more conventional kayaks.

 

Welcome to the forum,

I think you have two issues causing the stringers to twist out of plane. I have built about 12 kayaks and canoe like hulls and am familiar with the problem. The flare in the sides will determine how much shear (or "up turn" of the gunwale stringer) and the amount of rocker at the keel line with a flat bottom hull. The sides of the hull appear to be parallel in the drawing, that is the distance from the chine to the gunwale appears to be the same distance apart along the length hull, your frame appears to have not have the chine stringer and the gunwale parallel the length of the hull. Further more it appears you do not have enough rocker in the keel line as compared to the plans. Check both of these issues out as compared to the plans and make corrections accordingly.

You can force the stringers into a slight curve against their wide dimension, but it will not take much before it wants to twist the stringer unless it is square (like a 1" x1" chine stringer). Even than it will want to twist. The plywood will not want to lay flat against the stringers unless they are all in one plane with the plywood. For this to happen, the more flare in the hull the more rocker and shear (up turn) in the gunwales to keep everything in line.

It might help you to visualize this better if you take some card board and cut it into say 2" wide strips and than make a hull shape with them with various amount of flair, by pinching and taping the ends together, and see how it affects the rocker of the hull.

So you have some adjusting to do on your frame, unless you want to convert to a skin-on-frame construction and cover it with heavy fabric and paint. the fabric does not care what plane the stringers are in and will "warp" nicely to give a pleasing fair hull.

good luck.

 

and btw, that paddle in the plans really sucks (I made the mistake of making one that way once). That is a "white man" paddle, designed by those that do not depend on their paddles to stay alive.

I highley recommend you make a native type paddle, I like the Aleut type (though it is more work to make), but the Greenland type paddle is more popular. The Greenland type takes a slightly different stroke, but once you get used it almost no one ever goes back to a "white man" paddle.

here is a link to a good instruction video on making a Greenland paddle:

http://www.youtube.com/watch?v=c-vahYCW6Fs

here are some detailed plans and dimensions:

http://www.qajaqusa.org/QK/makegreen2.pdf

here are some decent plans for an Aleut style paddle:

 

I am researching the problem

Thanks for all the replies and helps. I will get to the paddle plans when I am confident it is safe for me to be on the water.

I need to look in detail at the framing. I've taken a few measurements to see if things are symmetrical. They aren't. I have to find out why and fix it obviously.
I'll get back with more info tomorrow. Thanks again for everyone's time and attention. It's a great help.

 

Take some more photos and post them. The stem in the photo doesn't look right, it should be attached to the keelson with screws through the keelson into the end of the stem. Do you have the 1 3/8" space between the end of the strongback and the keelson that gives you the 2" rocker of the bottom? Check all your measurements again. But more photos are needed.

 

This is a free design and it is worth every penny you paid. A flat bottomed kayak or solo canoe is a primitive design and an unpleasant thing to paddle. Been there, done that, it's very similar to my first naive design, which was a learing experience. It is quite high and very wide by kayak standards which means the paddle is going to bang on the hull. Ply-on-frame construction went out of style in the 50's with the advent of epoxy; it makes for a heavy boat.

This design will be difficult to build since the 1/2 x 2" chine log is 64 times more difficult to bend across the width than across the thickness. As you have already found it tries to twist so that more of the bending takes place across the thickness. As it is, if you plane the chine log to fit the plank properly you will remove so much material to remove the twist that the log will lose much of its strength. The usual way to control the twist in the logs is to have many frames; there is an example of that in the building manual at the same web source which shows the framework of a larger boat.

The kayak only has 2 frames and that's not enough. You can fix the twisting by simply attaching temporary battens - 1/2 x 2" battens every foot will do - between the chine logs and the sheer clamps; these will untwist the log. Make sure you can remove them after the planking is done, and have them 1/4" short so they don't get glued to the bottom plank. Caveat: a lot of force will develop as you untwist the logs so watch the entire assembly for signs of distress. IMHO 2" is far too wide for such a small boat and I would reduce it considerably, probably to around 1-1/4". Another way is to cut the curved chine logs and sheer clamps from a wide plank, use the straight pieces to measure the depth of the curve, which I estimate is about 3", and mark this on the plank using a batten, then cut - a handheld power saw will follow the curve, a table saw might snatch dangerously.

Once the twist is controlled you can plane the frames and the chine logs to fit both the sheer planks (sides) and the bottom plank. I suggest planing the bottom edges of the logs first, glue the bottom plank, then you can plane the plank and chine log outer edges together to fit the sheer planks. A well-sharpened plane is a pleasure to use, but give me a power plane every time, especially for planing ply edges. Don't try to use a power sander: it is not accurate enough to get a good fit and the dust can clog the grain and weaken the joint.

I wouldn't bother with glass fiber if I were you, this isn't going to be your favorite boat and you will probably want to do better later. That would be the time to buy a proper design that will have performance, lightness and elegance you can enjoy and be proud of. Treat this as a learning experience as I did and don't expect too much from this first effort. And good luck.

 

I'm thinking his issues are more to do with layout than the wood is asked to make difficult bends.

 

Wisgibson, Ancient Kayaer is not picking on you. He is a nice guy with a bunch of experience. He is telling like it is. Your boat is too wide and too tall to make a respectable kayak Do not let that stop you. Your boat is going to work out well and float nicely and with considerably more initial stability that a conventional kayak.

We are here to help you, not to criticize. Well OK sometimes we do, but never ever as a personal affront.

Keep us posted about your progress. Pictures maybe.

 

Greetings all and thank you for your sincere interest in my progress. I appreciate all comments and am not in the least offended by differing perspectives. I've always wanted to build boats, and now have the opportunity. I live very close to a the Fox River in WI and want to get on the water with my son. This plan I knew was simplistic for a kayak as I have spent time in modern roto-molded (sp?) sea kayaks on local lakes & rivers. But I need to learn the basic building skills, so I picked a freebee that looked reasonable. I don't live in an area where people build boats. Just tonight I mentioned to a friend that I am building a boat in my garage and he was stunned. So all the input I get from the wealth of experience around this forum gets processed for learning.

So on with the build...I have checked out the framing carefully. Frames orthogonal & plumb, stems straight on keelson CL. One sheer clamp runs a funny line, and will need altering. Maybe replaced, but I will look carefully at AncientKayaker's recommendation of temporary battens or frames. I hadn't thought of that.

Samsam noticed my stem error. I cut in the chine logs a bit farther back than I should have, forcing me to fair the stem into a bit of a taper.

I'll have pics soon. Thanks again!

 

If the chine logs meet sooner than they should have then the sheer clamps have to also meet sooner than they should, otherwise you start inducing the mismatching angles or supposed twist you're getting/seeing.

Looking at the photos again, the faces of the chine and sheer near the stem appear to be at the same angle as they are at the frame, and if the chine was allowed to move 'out' far enough, those two faces would be parallel so ply would lie flat.

There's a few other things that may contribute to the problem. The 1 3/8" space has to to be there between the ends of the keelson and the ends of the strongback.

There should be no exposed end grain on the chine end of the stem, it should all be covered by the keelson. Then when the taper was cut in the keelson, the stem edge would be planed down to a matching taper.

The plans could be wrong. The way they give a few measurements/angles are an odd way to do it.

 

@ Samsam: Because of my experience in building engineering and producing construction drawings, I have been suspecting that the plans could be wrong. I have carefully checked the 1 3/8" space you mentioned and I do have it built correctly for that. There are no details given of the stem to chines & sheer clamp (consequences of free plans) so I didn't know how to do it. Thanks for the clarity.

 

If you are putting up with a framed hull design, you should take advantage of the fact that you can fasten the frames to a rigid table for accuracy.

Trying to manipulate the frames and stringers 'freeform' is fraught with peril.

The boat will be fine for the thrill of getting into the water for the first time, but it will be a very poor performer. I would be loathe to waste money on good plywood for such a poor design.

Nevertheless, good luck with the build.