[Paddlewise] Planing

Nick wrote:
> It is
>possible Derek understands better than he lets on and he is just
>being lazy and doesn't want to write a in-depth text on hydrodynamics

I talked to Derek about this a while back and he did not have a clue. He may
have been lazy in not having a qualified person proof-read his book.
Britain has no lack of naval architects who could have set him straight on
numerous matters. The problem with facile explanations is that they confuse
people.

>But a surfing kayak is often planing, in that it's CG has been lifted
>and the drag is reduced. The fact that it is only capable of doing it
>by getting a power boost from an outside source doesn't change the
>way the boat moves through/over the water.

So a power boat is a kayak since the way it moves through the water is the
same as a boat using a paddle. :-)


> Maybe not all kayaks
>actually start planing in surf, but those that do so more readily are
>faster and generally considered "better" surfing boats.  This ability
>can be designed into the kayak. "Surfing" and "planing" are not be
>the same thing, but they can happen at the same time.

These things always cause problems.  However, Dr. Savitsky pointed out that
the rise in CG during surfing could occur but you could not call it planing
any more than you could say a person falling off a building was flying
because he generated some lift. The distinction between planing and not
planing is the vertical rise caused by the boat's power not an outside
source.

Why is it important? Maybe only because clarity and precision improves
understanding. Consider the confusion over "hull speed", "cavitation",
"lift", "sheer", etc. etc. that we have seen on this list. The English
language continues to evolve but it evolves to no one's benefit if fosters
confusion.

Both Matt and Nick have commented on the inappropriate drawing of
conclusions about boat types based on limited experience and paddlers would
do well to pay heed. Both Matt and Nick try to understand why boats do what
they do. I think that goes along way to explaining why people like their
designs.  Hydrodynamics is like a map. You can wander blindly about and
still get to your destination but if you have the map you might get there
sooner and without falling into the bog. Of course, you can pick the wrong
trail but that does not mean there is no "better" trail.

Sorry to see you go Jackie. The professor is despondent. He has taken to his
cage and refuses to come out or eat. I have see him  in this kind of funk
before and it is frightening. I just hope he can dig himself out.

Cheers,

John Winters



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