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Re: What about this?
By:Kris Buttermore
Date: 1/17/2008, 12:16 pm
In Response To: What about this? (Kudzu)

: But I am a curious person so
: I want to know why one design over the other. If it works better, why.

Here's my take on "why":

Because water optimally flows under the kayak and runs more or less straight from front to back along the buttock lines. You want the shape to direct and encourage this path - and not to be pushing more water out to the sides away from the kayak (as some mistakenly assume happens from looking at bow waves - which are just energy - not actual water transport).

The simplified wedge bow forces more water to the sides and can disrupt this flow path, whereas the more developed shape's twist assists the water to flow along the path of least resistance and thereby helps reduce resistance, turbulence, and helps to maintain laminar flow longer.

Compare your front views. Imagine the effect of flow over the forward third of the kayak.

The numbers you're running are not shown significant differences because they are NOT flow simulators. They're simple calculators factoring areas/ratios and such and can't account for the differences in the bow shapes.

Being small and skinny craft the differences can be small (all things relative), and kayaks can do OK with the simplified shape (look at Betsie Bay, some Polar Greenland, etc.). Because of this you'll get anecdotal accounts of it not mattering or even being better. Still, I'd say even in best cases the difference is detectable to the paddler - they just never get a chance to compare two kayaks that are the same otherwise - and so aren't really comparing at all, but rather are just giving an out of context interpretation based on a subjective perception of the kayak overall.

Simplest test: Look at two upturned hulls - one of each type - and I'm betting your eye would instinctively favor the tortured panels to the wedge.

Just check if the panels twist into one smooth face where the junction crosses the waterline. Not the same as the wedge issue, but an edge there can also introduce turbulence and drag as water flows around the chine edge if it comes too far forward/too high. Always tradeoffs though, and some designs do this intentionally for other reasons.

Messages In This Thread

S&G: Bow shape Does it make a difference? *Pic*
Kudzu -- 1/16/2008, 8:31 pm
Re: S&G: Bow shape Does it make a difference?
LeeG -- 1/18/2008, 1:49 pm
Re: S&G: Bow shape Does it make a difference?
Bill Hamm -- 1/20/2008, 3:28 am
Re: S&G: Bow shape Does it make a difference?
LeeG -- 1/21/2008, 2:11 pm
Re: S&G: Bow shape Does it make a difference?
Bill Hamm -- 1/20/2008, 3:28 am
Re: S&G: Bow shape Does it make a difference?
LeeG -- 1/18/2008, 1:44 pm
Re: S&G: Bow shape Does it make a difference?
Bryan Hansel -- 1/17/2008, 10:18 pm
Re: S&G: Bow shape Does it make a difference?
Robert McMurray -- 1/17/2008, 11:20 pm
Re: S&G: Bow shape Does it make a difference?
Kudzu -- 1/18/2008, 8:07 am
Re: S&G: Bow shape Does it make a difference?
HenkA -- 1/17/2008, 8:45 pm
What about this?
Kudzu -- 1/17/2008, 8:49 am
Re: What about this?
Bill Hamm -- 1/17/2008, 7:52 pm
Re: What about this?
Kris Buttermore -- 1/17/2008, 12:16 pm
Re: What about... Flat bottom vs V speeds
Toni V -- 1/20/2008, 7:50 am
Re: What about... Flat bottom vs V speeds
Kudzu -- 1/20/2008, 4:24 pm
Re: What about this?
HenkA -- 1/17/2008, 8:52 pm
Re: What about this?
Kris Buttermore -- 1/22/2008, 2:32 pm
Re: What about this?
HenkA -- 1/24/2008, 10:30 pm
Re: What about this?
LeeG -- 1/18/2008, 1:59 pm
Re: What about this?
Toni V -- 1/17/2008, 3:09 pm
Re: What about this?
Kris Buttermore -- 1/22/2008, 2:19 pm
Re: What about this?
Bill Hamm -- 1/23/2008, 2:23 am
Re: What about this?
Kudzu -- 1/17/2008, 9:02 pm
Re: What about this?
Allan Cole -- 1/17/2008, 7:08 pm
Re: What about this?
Allan Cole -- 1/18/2008, 1:39 pm
FrreShip Flow line were useless. *NM*
Kudzu -- 1/17/2008, 2:55 pm
Re: What about this?
Kudzu -- 1/17/2008, 1:37 pm
Re: What about this?
Alex Ferguson -- 1/17/2008, 5:43 pm
Re: S&G: Bow shape Does it make a difference?
Toni V -- 1/17/2008, 3:52 am
Re: S&G: Bow shape Does it make a difference?
Tom Simpson -- 1/18/2008, 7:05 pm
Re: S&G: Bow shape Does it make a difference?
Bill Hamm -- 1/17/2008, 1:42 am