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Re: Kayak-ified Surf Skis
By:anewhouse
Date: 5/13/2014, 10:35 pm
In Response To: Re: Kayak-ified Surf Skis (Björn Thomasson)

if you fx change LOA, BOA and height by x, the results would be that the speed changes with the square root of x, the linear dimensions with x, the wetted surface with x2, displacement and drag by x3, stability by x4 and inertia by x5

That is one reason why people should be wary of making anything more than small changes to a proven design. The impact of scaling on some of the kayak's behaviour is much greater than the impact on other aspects and much greater than most people realise.

Some changes also have effects that some people might not realise will occur. It may not be immediately obvious to everyone that reducing the length will slightly reduce the stability, even if the width remains the same.

The impact on stability of scaling a kayak down is much greater than most people think it would be. To the uninitiated, it might seem that a 10% reduction in width would mean a 10% reduction in stability. Anyone who did that would be in for a big surprise. I think it is closer to a 35% reduction.

Messages In This Thread

Review: Freya' FREYA review *PIC*
Etienne Muller -- 5/6/2014, 11:26 am
Re: Review: Freya' FREYA review
JohnAbercrombie -- 5/6/2014, 1:28 pm
Re: Review: Freya' FREYA review
Ancient kayaker -- 5/7/2014, 4:53 pm
Re: Review: Freya' FREYA review
JohnAbercrombie -- 5/7/2014, 5:58 pm
Re: Review: Freya' FREYA review
Mike Bielski -- 5/7/2014, 11:55 pm
Re: Review: Freya' FREYA review
JohnAbercrombie -- 5/8/2014, 1:10 am
Re: Review: Freya' FREYA review
Björn Thomasson -- 5/8/2014, 5:55 am
Re: Review: Freya' FREYA review
Mike Bielski -- 5/8/2014, 2:36 pm
Re: Review: Freya' FREYA review
JohnAbercrombie -- 5/8/2014, 3:21 pm
Re: Review: Freya' FREYA review
mick allen -- 5/8/2014, 11:25 pm
Re: Review: Freya' FREYA review *PIC*
JohnAbercrombie -- 5/9/2014, 1:08 am
Re: Review: Freya' FREYA review
Dan Caouette (CSCWC) -- 5/8/2014, 4:21 pm
Re: Review: Freya' FREYA review
Mike Bielski -- 5/12/2014, 4:34 pm
Re: Review: Freya' FREYA review
Robert W -- 5/8/2014, 3:33 pm
Re: Review: Freya' FREYA review
JohnAbercrombie -- 5/8/2014, 3:58 pm
Kayak-ified Surf Skis *PIC*
Dan Caouette (CSCWC) -- 5/8/2014, 4:46 pm
Re: Kayak-ified Surf Skis
JohnAbercrombie -- 5/8/2014, 5:37 pm
Re: Kayak-ified Surf Skis
Dan Caouette (CSCWC) -- 5/9/2014, 8:30 am
Re: Kayak-ified Surf Skis
Björn Thomasson -- 5/9/2014, 1:56 pm
Re: Kayak-ified Surf Skis
Dan Caouette (CSCWC) -- 5/12/2014, 6:32 am
Re: Kayak-ified Surf Skis
Robert W -- 5/12/2014, 10:47 am
Re: Kayak-ified Surf Skis
Björn Thomasson -- 5/12/2014, 11:34 am
Re: Kayak-ified Surf Skis
Robert W -- 5/13/2014, 2:56 pm
Re: Kayak-ified Surf Skis
Nick Schade - Guillemot Kayaks -- 5/13/2014, 4:04 pm
Re: Kayak-ified Surf Skis
Björn Thomasson -- 5/13/2014, 4:19 pm
Re: Kayak-ified Surf Skis
anewhouse -- 5/13/2014, 10:35 pm
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/12/2014, 7:27 pm
Re: Kayak- Surf Ski-ified
JohnAbercrombie -- 5/12/2014, 11:58 pm
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/13/2014, 8:18 am
Re: Surf ski-ified Kayak *PIC*
Dan Caouette (CSCWC) -- 5/13/2014, 9:14 am
Re: Surf ski-ified Kayak
Marc Upchurch -- 5/13/2014, 4:45 pm
Re: Surf ski-ified Kayak
Dan Caouette (CSCWC) -- 5/13/2014, 5:05 pm
Re: Surf ski-ified Kayak
Björn Thomasson -- 5/14/2014, 2:39 am
Re: Kayak- Surf Ski-ified
Bill Hamm -- 5/13/2014, 12:53 am
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/13/2014, 8:22 am
Re: Kayak- Surf Ski-ified
Bill Hamm -- 5/14/2014, 1:21 am
Re: Kayak- Surf Ski-ified
Björn Thomasson -- 5/14/2014, 2:43 am
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/14/2014, 12:57 pm
Re: Kayak- Surf Ski-ified
Craig -- 5/15/2014, 2:59 am
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/15/2014, 4:39 pm
Re: Kayak- Surf Ski-ified
Craig Robinson -- 5/16/2014, 12:59 am
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/16/2014, 8:51 am
Re: Kayak- Surf Ski-ified
Craig -- 5/16/2014, 11:04 pm
Re: Kayak- Surf Ski-ified
Craig -- 5/16/2014, 11:06 pm
Re: Kayak- Surf Ski-ified
Craig -- 5/16/2014, 11:08 pm
Re: Kayak- Surf Ski-ified
Bill Hamm -- 5/18/2014, 12:16 am
Re: Kayak- Surf Ski-ified
Craig -- 5/18/2014, 3:06 am
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/16/2014, 11:16 pm
Re: Kayak- Surf Ski-ified
Etienne Muller -- 5/17/2014, 3:52 am
Re: Kayak- Surf Ski-ified
Craig -- 5/17/2014, 6:02 am
Re: Kayak- Surf Ski-ified
JohnAbercrombie -- 5/17/2014, 12:15 pm
Re: Kayak- Surf Ski-ified *PIC*
JohnAbercrombie -- 5/17/2014, 12:44 pm
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/17/2014, 8:19 pm
Re: Kayak- Surf Ski-ified
JohnAbercrombie -- 5/17/2014, 8:54 pm
Re: Kayak- Surf Ski-ified
Marc Upchurch -- 5/17/2014, 9:15 pm
Re: Kayak- Surf Ski-ified
Bill Hamm -- 5/18/2014, 12:18 am
Re: Kayak- Surf Ski-ified - Thanks
Marc Upchurch -- 5/18/2014, 10:03 am
Re: Kayak- Surf Ski-ified
Bill Hamm -- 5/15/2014, 2:31 pm
Re: Kayak-ified Surf Skis Correction
Marc Upchurch -- 5/12/2014, 7:32 pm