Lofting question

Joined
Feb 17, 2014
Messages
327
Location
CT
I'm getting started lofting a Freedom 17 from the Canoecraft book, I understand that I need to subtract the strip thickness from the lofted dimensions. What about the stem forms? If the lofting dimensions represent the final profile of the bow and stern, it seems like I will have to subtract substantially more than the strip thickness because of the angle the strips come into the ends.

Do I just take a stab at and check fairness? I'm guessing that's what I have to do but thought I should check before I start cutting wood.

Stripperguy, I really wanted to build a Kite after watching your build, but I think I should do a tandem first so I can get my kids more involved. Maybe the next one.

Thanks.

Thanks.
 
Joined
Feb 29, 2012
Messages
1,820
Location
Schenectady, NY
wtsedav,
If you're using 3/16 strips, do you even need to consider their thickness? Are you building the hull to fit to some specific criteria, like a race requirement?
Even so, you could safely subtract the 3/16 from all forms, to stay within the supplied dimensions. BTW, some plans specify whether or not a hull thickness allowance is already calculated.
As far as the stems, are you building with stem pieces? or just joining the strips from each side? If you are just joining the strips at the stems, the strips usually extend beyond the form by an inch or two...exactly how much is a function of how blunt or slender the stems are. You can always cut the stem forms and temporarily mount them and verify a fair shape with a few strips before solidly mounting those stem forms. Even easier than a field verification would be a CAD layout...do you have access to any CAD software? It really simplifies the form layout, all of them, not just the stem forms...Especially if you are offsetting for the hull thickness, it's just too easy with CAD!!

I have that book at home...I can look at those offsets later. Are you building soon? I can determine the stem positions from a partial CAD layout...

Lastly, I'm very pleased with the Kite, but I've decided to build another one in the spring and pay more attention to the weight. I just helped a buddy glass the outside of an Osprey, and his hull came off the forms at 20 lbs!! My build finished at 31 lbs, waaaay too heavy for my sort of travel.
 
Joined
Jan 8, 2014
Messages
1,133
Location
Minden, NV
Call me a dinasour, but I can't stand CAD software. It takes all the art out of a thing like a canoe. It turns it into a math function.

Is 3/16 " really going to matter that much? Maybe if the design seems narrow you build on the full forms without subtraction. If the design seems beamy, subtract for the thickness of the strips.
 
Joined
Jun 12, 2014
Messages
3,340
Location
NW Iowa
I can't remember what he recommends in that book but I've built mine stemless and I use a belt sander to taper the edges of the stems. Kind of hard to tell by looking at the picture but I'd guess the strips are extending about 1/2" past the stems, maybe a little more. The strips are 5/32" to give you an idea of scale. I'd think a boat with more blunt ends wouldn't extend quite as far. Final sanding brought them back a little farther as well.

I roughly beveled the stems on the bench and then mounted them in place. Then I could hold short strips in place to see if the angle was correct, which of course it wasn't, so then I just touched them up in place with the belt sander until the strips lay nicely against the stems.

20140705_011 by Alan Gage, on Flickr

Alan
 
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