sheer strip angle.

Submitted byJ.auger onMon, 05/14/2018 - 15:06
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Kayak Building

Hello. I am building my second kayak using Nicks books. I built the guillemot from the last book and it came out great despite it being my first boat and not having taken any classes. This time around, I am building the Petrel from Building Strip Planked Boats. I am taking care to do things correctly and without haste. I am trying to figure out how to set the angle for the sheer strip. I understand the rolling bevel and all of that. I just cant figure out how to set the angle. I have scoured the videos and books for the sheer angle information and can only find one line that says "draw a line that marks an angle halfway between the deck side and the hull side" I thought that this meant to draw an angle line from the sheer line to the middle of the form. the mid point between the hull and the deck. this makes too steep of an angle in many places. watching the videos i see the angle not being anywhere steep as what i ended up with.  You all have been a great help in the past. Thanks.

Etienne Muller

Mon, 05/14/2018 - 16:17

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The main thing is that the hull and deck meet at a convenient angle.

I would strike perpendicular lines off tangents at the sheerline. Mark them on the formers, and use them to angle the hull sheer strip and the deck sheer strips later.

The easier option though, is to put the angle on the hull strip when starting the hull - then, once the hull is complete, but before glassing it, or removing it from the forms, bevel the first deck strips at the sheer, using the hull sheer strip as a guide for the bevel. Then attach it and carry on as usual.

Et

Most of the back deck, and the front couple of feet of the front deck, meet the hull at a very sharp angle or chine. So if the sheer strip in those locations is beveled to about 45 degrees the joint bisects that angle. 

But around the front of the cockpit and the foredeck the hull-deck joint is pretty much a straight line - the sides of the deck are vertical, so if you bevel the sheer strip then it makes a very sharp transition from 0 to 45 degrees, which is hard to do, as the forms get in the way.

I've tried both beveling and leaving it at 0 degrees, both are quite hard, but beveling produces a better final result, in my humble opinion. Just do as Et says above.

Justin

I cheat - - - - After building the deck and hull I set them together and insert a 1/4" thick x 2" wide by 36" long strip of wood between them that has 80 grit sandpaper glued to both sides. A few strokes with this sanding board the length of the boat results in a perfectly matched deck / hull sheer.

Hello again. all of your advice helped me set up the initial beveled strip. Ive been using Nicks robo-bevel to lay a nice bevel and now I am at the hull chine. In his videos, the kit forms have these bevels laid out on the forms as a guide on where to trim the extra wood. My problem is that these bevel lines were not provided in the book offsets. so ive been staring at the kayak and not doing anything because i am unsure how to proceed. Its the petrel and the strips are too wide to make the hard turn on the hull chine by the seat. How do I lay the line to trim the extra wood off?

Allan Newhouse

Sat, 06/30/2018 - 17:59

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I use the same technique as Randy.  It is quick, easy and effective.

If the strips are too wide to sit close to the forms on the hard turns, rip the strips narrower.

If you lay a couple of spare strips flat on the hull, and cut the sides level with them, then that will give you the right height for the top of the bevel.

I.e. since the hull is upside down, the bottom of the hull is upwards. Lay the loose strips on top, cut or plane to that height, and then bevel at around 45 degrees where the hard chine is, rolling off to not much forward of the cockpit where the hull is rounded, with no chine.

Hope this is clear and helps?

Drawing a line perpendicular to a line tangent to the curve of the form at the sheer line will yield an equal bevel on the deck and hull strips. You can use a t-square to do so.

Clamp a short (6" or so) strip to each form along the perpendicular line and projecting past the strips -- doing so reveals the amount of bevel needed in the hull and deck strips at that point.  Just mate the beveled edge to the clamped stick.

JayBabina

Thu, 10/18/2018 - 17:24

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Some interesting mathematical solutions to the problem. My problem is that you still have to cut the angle.

I have never built a Petrel but have done some strong back deck shear curves. I cut my regular 3/4 strips in half. Often my angle is 45 degrees. I  use a squeeze clamp and mark my stations on the strip. Then I just go section by section and bevel that angle pressing it into the proper position to check the fit. I use a low angle plane. As long as I favor the outside fit, I can tolerate a lesser than perfect on the inside. When I do my inside glassing, I just pull a finger of epoxy putty over any no-so-good fits and press the cloth into it and glass the inside. Its one of those things that just gets better and better as your craftsmanship gets better. Its a rolling bevel so it will always need some hand work.  I enjoy doing rolling bevels.

I can't control myself here, I keep reading these, "make a mountain out of a mole hill" solutions. I have to repost this method that takes 5 minutes and works perfect, almost zero brain power required which made it an easy solution for me . . . . . OK - I shutup !

"I cheat - - - - After building the deck and hull I set them together and insert a 1/4" thick x 2" wide by 36" long strip of wood between them that has 80 grit sandpaper glued to both sides. A few strokes with this sanding board the length of the boat results in a perfectly matched deck / hull sheer."

Hi Randy,

He's past the sheerstrip, and asking for help on the hard chine now.

By the way I agree with your solution for matching the sheer.......

Justin

I misunderstood the question, sorry.

I need to pay more attention before opening my mouth :(

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Strip Built