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Re:Scaling Designs To Get a Larger Version of Same Boat
By:Nick Schade
Date: 5/29/1998, 7:35 pm
In Response To: Re:Scaling Designs To Get a Larger Version of Same Boat (Rob Cochrane)

Cp and Cb are not changed by scaling. They are non-dimensional and based purely on the shape of the boat. Try changing the units of measurement, and you will see that Cp and Cb do not change. As long as the design waterline stays in the same relative location, the design is not changed. This does not mean that the boat will handle in a "proportional" manner. Relative surface area and speed-length ratio will change and thus the "optimum" Cp and Cb will no longer be the same, but for small scale changes, a simple proportional scaling would work fine.

> Hi Mark

> Even in sail boats a direct scaling would only work for a small
> change.

> Remember the cube rule!!

> Factors like Cp Cb start to react badly on a direct scaling.
>

> Further, one knows that in a Kayak a Beam (max) of between 19"
> & 25/6" is about all you need for a length up to twenty plus
> feet.

> I would think that the sort of specs I would be looking at are
> a Beam (max) of no more than 24" - Beam wl of about 17"to
> 18" LOA of about 20' Depth at knees of 13 to 14"

> Careful placement of CG around LCB and a draft of no more than
> 4 or 5 inches.

> Rob

Messages In This Thread

Cigars for everyone!
Rick Rubio -- 5/28/1998, 1:56 pm
Re: Thanks for all the advice!!!
Brian W -- 5/29/1998, 6:36 am
Re: How to link specifically when frames are used.
Mark Kanzler -- 5/29/1998, 10:29 am
Re: Cigars for everyone!
Mark Kanzler -- 5/28/1998, 3:26 pm
Re: Cigars for everyone! Not Mark
Rob Cochrane -- 5/28/1998, 5:38 pm
Re: Cigars for everyone! Not Mark
Nick Schade -- 5/29/1998, 7:08 pm
Re: Cigars for everyone! Not Mark
Wes Boyd -- 5/30/1998, 12:18 pm
Re: Cigars for everyone! Not Mark
Mark Kanzler -- 5/29/1998, 7:57 pm
Re: Big or "up-scaled" designs
Tor-Henrik Furmyr -- 5/29/1998, 7:42 pm
Re: Cigars for everyone! Not Mark
Mark Kanzler -- 5/29/1998, 10:39 am
Re: Cigars for everyone! Not Mark
Dan Lindberg -- 5/30/1998, 12:42 am
Re: Cigars for everyone! Not Mark
Mark Kanzler -- 5/29/1998, 2:11 pm
Re: Cigars for everyone! Not Mark
Mark Kanzler -- 5/29/1998, 1:11 pm
Re: Cigars for everyone! Not Mark
Rob Cochrane -- 5/29/1998, 3:23 pm
Re: Cigars for everyone! Not Mark
Nick Schade -- 5/29/1998, 7:24 pm
Re Scaling plans
Roger Tulk -- 5/30/1998, 2:07 pm
Re: Twelve step program
Mark Kanzler -- 5/31/1998, 4:22 pm
Re: Twelve step program
Mark Kanzler -- 5/31/1998, 4:44 pm
Re: Twelve step program
Tor-Henrik Furmyr -- 5/31/1998, 6:27 pm
Re: Twelve step program
Roger Tulk -- 5/31/1998, 6:44 pm
Re: Re Scaling plans
Paul Jacobson -- 5/31/1998, 1:52 am
Re: Re Scaling plans
Mark Kanzler -- 5/31/1998, 4:28 pm
Re: Re Scaling plans
Mark Kanzler -- 5/31/1998, 4:41 pm
Re: Re Scaling plans
Roger Tulk -- 5/31/1998, 3:23 pm
Re: Re Scaling plans
Paul Jacobson -- 5/31/1998, 8:28 pm
Re: Re Scaling plans
Roger Tulk -- 5/31/1998, 10:08 pm
Re: Re Scaling plans
Nick Schade -- 5/31/1998, 3:51 pm
Re: Re Scaling plans
Roger Tulk -- 5/31/1998, 6:50 pm
Re: Re Scaling plans
Mark Kanzler -- 5/31/1998, 4:32 pm
Re: Re Scaling plans
Rick C. -- 5/30/1998, 2:33 pm
Re:Scaling Designs To Get a Larger Version of Same Boat
Mark Kanzler -- 5/29/1998, 3:31 pm
Re:Scaling Designs To Get a Larger Version of Same Boat
Rob Cochrane -- 5/29/1998, 5:53 pm
Re:Scaling Designs To Get a Larger Version of Same Boat
Nick Schade -- 5/29/1998, 7:35 pm
Re:Scaling Designs To Get a Larger Version of Same Boat
Rob Cochrane -- 5/30/1998, 5:16 pm
Re:Scaling Designs To Get a Larger Version of Same Boat
Mark Kanzler -- 5/29/1998, 6:38 pm
Re:Scaling Designs To Get a Larger Version of Same Boat
Mike Spence -- 5/29/1998, 5:04 pm
Re:Scaling Designs To Get a Larger Volume
Tor-Henrik Furmyr -- 5/29/1998, 6:26 pm
Re:Scaling Designs To Get a Larger Volume
Mark Kanzler -- 5/29/1998, 7:52 pm
Re:Scaling Designs To Get a Larger Version of Same Boat
Mark Kanzler -- 5/29/1998, 6:25 pm
Re: Cigars for everyone! Not Mark
Dan Lindberg -- 5/29/1998, 1:45 pm
Re: Cigars for everyone! Not Mark
Mark Kanzler -- 5/29/1998, 2:09 pm
Re: Cigars for everyone! Not Mark
Mark Kanzler -- 5/29/1998, 10:22 am
Re: Cigars for everyone! Not Mark
Rick C. -- 5/29/1998, 11:55 am
Re: Cigars for everyone! Not Mark
David Dick -- 5/30/1998, 12:47 am
Re: NOW you tell me!
Rick C. -- 5/29/1998, 11:11 pm
Re: NOW you tell me!
Roger Tulk -- 5/31/1998, 12:05 am
Re: NOW you tell me!
Rick C. -- 5/30/1998, 2:29 pm
Re: NOW you tell me!
Mark Kanzler -- 5/31/1998, 4:51 pm
Re: NOW you tell me!
Mark Kanzler -- 5/30/1998, 9:08 am
Re: Flexibility
Roger Tulk -- 5/30/1998, 12:34 am
Re: Cigars for everyone! Not Mark
Mark Kanzler -- 5/30/1998, 12:13 am
Re: Cigars for everyone! Not Mark
Rick C. -- 5/29/1998, 10:47 pm
Re: Cigars for everyone! Not Mark
Rgoer Tulk -- 5/29/1998, 10:41 am
Re: Cigars for everyone! Not Mark
Rob Cochrane -- 5/29/1998, 3:15 pm
Re: Cigars for everyone! Not Mark
Roger Tulk -- 5/31/1998, 12:17 am
Re: Cigars for everyone! Not Mark
Jerry Weinraub -- 5/31/1998, 3:05 pm
Re: Cigars for everyone! Not Mark
Wes Boyd -- 5/28/1998, 11:09 pm
Re: Displacement issue...
Tor-Henrik Furmyr -- 5/28/1998, 6:51 pm