Re: [Paddlewise] Why does rocker and carving work?

Nick wrote:
<SNIP>>>Leaning the boat can have many different effects depending on the
design of the boat, but one effect is almost universal regardless of
the kayak. Because kayaks get narrow towards the ends, when you lean
the boat you give it more rocker and more rocker makes it easier to
turn (see above).<<<<<<

In the paddle flutter discussion I am in near total agreement with Nick.
Here though, I think there is a slight flaw in his explanation.
Imagine a perfectly cylindrical "torpedo" floating on the surface with a
draft of 1/2 its diameter (and also having narrow ends) would not change its
shape in the water or any handling characteristics by being tilted even
though the ends might be narrow. Therefore the easier turning isn't just due
to pointed ends. The reason a kayak turns easier when leaned (to either
side--into or away from a turn) is that kayaks are usually wider from the
midline than they are deep below the water so there is more curvature on the
sides of the kayak than on the bottom. Leaning this shape puts the wider
middle deeper into the water and the now more curved underwater shape
decreases the depth of the ends (and often shortens the waterline as well
especially if keels that are now shifted to the side are involved).
 Just what effect this tilt will have on a moving kayak will depend on a
number of things such as the amount of lean, the relative depth, length,
fineness and "V" angle of the keels at the bow and stern, and the shape of
the kayak including chines and the longitudinal distribution of buoyancy.

I'm a dealer so like other dealers I hear a lot of problems people have with
their equipment. Some is due to faulty equipment but most likely it is due
to some lack of understanding on the paddlers part about how to use the
equipment or a false belief about what the equipment should be doing for
them. While it might be more profitable to sell the paddler on a material
solution (product) I think it is more profitable in the long run to help the
paddler solve the problem most efficiently and with the least expenditure.
The retailer will most likely be rewarded with repeat business and good word
of mouth advertising from that customer.

Matt Broze
http://www.marinerkayaks.com

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