Building the hull problem..

woodman

Curious about Wooden Canoes

So as you guys can see in the pictures there is a pretty good bow of the strips between station 1 and 3. That bow of the strips is consistent on both the Bow and Stern of the boat. And also on both sides of the hull. My question is what would cause something like that. Hopefully you can see in the other picture that the first few strips starting at the sheer seem to have a fairly nice curve. this problem only occured in the last few strips.

To answer anyquestions that may come up this is a laughing loon solo portage. Molds were cnc cut. There perfectly centered top and bottom. And the strips on station 2 are making the same contact as when started. Is there anything i can do to fix it? It just seems like that is no way the inteded shape of the hull.
 
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There might be some kind of permission required to allow others to see your images:
upload_2019-3-26_20-29-41.png
 
Double checked spacing and its all good. I got this picture off the link you posted dan. Near the top right side of the boat it looks like that is what im describing. I cant exactly tell if its a play on light or not. But my "problem" seems to be consistent on both ends and sides of the boat. So what is the reasoning for a hollow spot in the water line?
sp.tan.jpg
 
Did you cut the forms yourself? it looks like your form stations are not fair. Like Dan said if the spacing is correct, then you might have a bad station since that looks more like its not fair than a hollow in the design. Perhaps batten the form where its not stripped and that should show you what is happening.
 
I bought the stations they were cnc cut. I cut out the mold patterns from the paper plans and i checked a few of the forms and theyre right on. I tripple checked the form spacing and i am off a 1/16 from station 2 to 1 on both ends of tbe boat. I was using a old tape measure with a wonky end when i initally set everything up. Its just hard to believe that 1/16 would be the cause, when from the sheer line up a few strips the curve looks correct. and i tried a dry fit strips higher up and the hollow spot seems to get worse.
 
This could be the design.

I had typed up a remedy, that came to mind, but after a closer look, and your responses, I believe it's the design.

A thought, is to just not staple to that form, until the strips come more back inline.

Your call ! Or make a call (email) to Laughing Loon.

Good luck !
 
If it's the design ? I'd say it's unusual.

as suggested, check the forms with a "Fairing" strip.

Check the tops of the forms, for height ! If they are all the same. And the spacings are on, then it's the design.

You could live with it, or pull the staples, at the offending forms. Continue stripping the hull, skipping those forms, until it comes beck to Fair !

It would be a lot easier to diagnosis, if I was standing in your Shop !

Good Luck !

Jim
 
Have you contacted the person/organization who sold you the stations? It is possible that this is a bug or a feature.

Benson
 
I havent contacted the company yet, i wanted to be sure it wasnt my fault before i did that.

So I checked the tops of the forms and they do not all line up... somehow the strongback developed a slight sag in the middle. So that sunk the center station and station 4 slightly. Station 3 and station 1 line up correctly. Somehow tho station 2 is about 1/8 low too. This is true for both ends of the canoe. So my sags are consistent. Both 4 and 2 are low and 1 and 3 line up.

So could the station being slightly low be the problem? I did what jim suggssted and pulled the strips away from the offending form and shimed it so it would stay. I did some test strips to see when it would become a fair curve again. It will be a few short of the center when it can touch the offending form again and look correct. Im pretty happy with the way it looks now. Im just gonna do that where it needs it and keep building. Unless you guys think that the stations being slightly up and down isnt the culprit and it is the forms themselves.


 
It'll be OK !
Looking at your first pic, there seemed to be quite a variation in strip thickness, of your test strips ! I know they are probably just used to check Fair, but I'm curious how you cut your strips for your build ?

Jim
 
A few of the test strips werent seated together properly so it looks like bad thickness. I made my strips by sawing a actual 2x8 into 3/4 chunks then sawed those 3/4 by 2 pieces into a bunch or 1/4 strips. Everything was also planed to the same thickness.
 
You'll find that a lot of things spring-back when the hull releases from the forms. If one form on a 16' boat is a bit off it will probably

If your strong-back went out of whack are you confident it is stable? Are you going to chase it for the whole strip/fair/smooth/epoxy process?

From my own experience the quickest and easiest part of the whole build is the first 10 strips up the side. If that is all the further you are I would consider starting over - making sure you're confident in your strongback and form alignment. It would make me really nervous putting in all the hours and material not knowing you're starting from a sound foundation.
 
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