Boat Building Forum

Find advice on all aspects of building your own kayak, canoe or any lightweight boats

Re: S&G: Plate development
By:Nick Schade - Guillemot Kayaks
Date: 12/3/2016, 10:14 pm
In Response To: S&G: Plate development (Hubert Schreier)

I have not delved into the math of Developable surfaces for awhile, but I can say from practical experience that the bottom panel of a S&G kayak can be tricky.

My take on it is: Developable surfaces assume a panel that is 4 edges on a kayak this translates to: Chine, Keel, Bow and Stern Stems. But in reality the Keel and two stems are continuous, often with fair curvature from the keel to the stem, so the surface has two edges and translating the 4 edges of the developable surface to 2 creates more twist.

For the Developable surface with 4 edges the stems must be straight, otherwise it can't develop. But this will create a kink in the plywood at the base of the stem adjacent to the keel. To make this in plywood you need to cut off the corner between the keel and the stem, rounding out the stems and creating a smooth transition between keel and stem.

Using NURBS surfaces I've dealt with this in two ways, instead of being 1st degree NURBS in the Keel-to-Chine direction, I will use 2nd or 3rd order surfaces and fake a developable surface, i.e make a surface that maybe developed even if it is not strictly Developable.

Another way is to run the surfaces past the centerline and trim it back to the centerline. This can allow you to create a surface that is developable but only use part of it to create the desired shape.

upchurchmr's suggestion of the BoatDesign forums is a good one, there may be participant there who have dealt more with the math, instead of just finding techniques to hack what is available into a solution that can be built.

Messages In This Thread

S&G: Plate development
Hubert Schreier -- 12/3/2016, 4:10 pm
Re: S&G: Plate development
upchurchmr -- 12/3/2016, 4:38 pm
Re: S&G: Plate development
Hubert Schreier -- 12/3/2016, 4:55 pm
Re: S&G: Plate development
upchurchmr -- 12/3/2016, 5:45 pm
Re: S&G: Plate development
Nick Schade - Guillemot Kayaks -- 12/3/2016, 10:14 pm
Re: S&G: Plate development
Hubert Schreier -- 12/4/2016, 12:57 am
Re: S&G: Plate development
upchurchmr -- 12/4/2016, 3:37 am
Re: S&G: Plate development
Hubert Schreier -- 12/4/2016, 11:45 pm
Re: S&G: Plate development
Alex Ferguson -- 12/5/2016, 3:38 pm
Re: S&G: Plate development
upchurchmr -- 12/5/2016, 5:42 pm
Re: S&G: Plate development
Hubert Schreier -- 12/5/2016, 9:23 pm
Re: S&G: Plate development
Alex Ferguson -- 12/5/2016, 9:55 pm
Re: S&G: Plate development
Hubert Schreier -- 12/6/2016, 12:34 am
Re: S&G: Plate development
Nick Schade - Guillemot Kayaks -- 12/4/2016, 8:20 am
Re: S&G: Plate development *PIC*
Hubert Schreier -- 12/5/2016, 10:23 pm
Re: S&G: Plate development
Bill Hamm -- 12/6/2016, 12:56 am
Re: S&G: Plate development
Hubert Schreier -- 12/6/2016, 1:03 am
Re: S&G: Plate development
Bill Hamm -- 12/6/2016, 1:09 am
Re: S&G: Plate development
Hubert Schreier -- 12/6/2016, 1:20 am
Re: S&G: Plate development
Mike Bielski -- 12/6/2016, 1:09 pm
Re: S&G: Plate development *PIC*
Hubert Schreier -- 12/6/2016, 3:07 pm
Re: S&G: Plate development
Mike Bielski -- 12/6/2016, 4:35 pm
Re: S&G: Plate development
upchurchmr -- 12/6/2016, 7:14 am
Re: S&G: Plate development
Hubert Schreier -- 12/6/2016, 8:45 am
Re: S&G: Plate development
Nick Schade - Guillemot Kayaks -- 12/6/2016, 8:49 am
Re: S&G: Plate development
Hubert Schreier -- 12/6/2016, 10:04 am
Re: S&G: Plate development
upchurchmr -- 12/6/2016, 11:04 am
Re: S&G: Plate development *PIC*
Nick Schade - Guillemot Kayaks -- 12/6/2016, 7:29 pm
Re: S&G: Plate development
Hubert Schreier -- 12/6/2016, 8:26 pm
Re: S&G: Plate development *PIC*
Hubert Schreier -- 12/7/2016, 12:27 am
Re: S&G: Plate development
Nick Schade - Guillemot Kayaks -- 12/7/2016, 7:45 am
Re: S&G: Plate development
upchurchmr -- 12/7/2016, 9:29 am
Re: S&G: Plate development
Nick Schade - Guillemot Kayaks -- 12/7/2016, 10:21 am
Re: S&G: Plate development
upchurchmr -- 12/7/2016, 12:43 pm
Re: S&G: Plate development *PIC*
Hubert Schreier -- 12/13/2016, 4:00 am
Re: S&G: Plate development *PIC*
Nick Schade - Guillemot Kayaks -- 12/13/2016, 6:54 pm
Re: S&G: Plate development
Hubert Schreier -- 12/13/2016, 8:03 pm
Re: S&G: Plate development *PIC*
Nick Schade - Guillemot Kayaks -- 12/13/2016, 11:10 pm
Re: S&G: Plate development
Hubert Schreier -- 12/30/2016, 6:08 pm
Re: S&G: Plate development *PIC*
Dan Caouette (CSCWC) -- 12/14/2016, 6:55 am
Delftship
Nick Schade - Guillemot Kayaks -- 12/14/2016, 8:50 am
Re: Delftship *PIC*
Dan Caouette (CSCWC) -- 12/14/2016, 11:57 am
Re: Delftship
Nick Schade - Guillemot Kayaks -- 1/25/2017, 9:41 am
Re: Delftship
Dan Caouette (CSCWC) -- 1/25/2017, 6:19 pm
Re: S&G: Plate development
Hubert Schreier -- 12/30/2016, 5:53 pm
Re: S&G: Plate development
Dan Caouette (CSCWC) -- 12/31/2016, 8:57 am
Find "MultiConic Dev of Hull Surfaces"
mick allen -- 12/5/2016, 8:16 pm
Re: Find "MultiConic Dev of Hull Surfaces"
Hubert Schreier -- 12/5/2016, 11:07 pm