Re: [Paddlewise] planing

From: "Peter Rathmann" <prathman_at_attbi.com>

> I would define surfing as occuring when the boat is propelled forward
> relative to the water as a result of its position on the forward portion
> of a wave. I.e. the boat moves forward because gravity pulls it down the
> sloping face of the wave (which can be either advancing or standing). As
> with planing, there's room to quibble about how fast and/or far the boat
> must be propelled before it's 'really' surfing.

Actually, that probably isn't surfing, though most people refer
to it as such (Hey - might as well stir up the nest a little!)

I guess we have to differentiate between riding on a breaking wave
versus riding on a non-breaking wave. Correct me if I'm wrong on
this: (As if I have to ask:-)

You move on a non-breaking wave because gravity pulls you downhill, 
as you described above.  In general, however, you can't sustain
this motion without adding some paddle power.

You move on a breaking wave because of both gravity and the fact
that the water is moving down the face of the wave.  That water
flow is not at a constant rate and is faster up the wave than 
down near the trough.  As a result, the stern can be pushed while
the bow is being retarded by slower (or even reverse motion) water
near (in) the trough.

I'm not at all certain, but I would guess that you can only reasonably
surf (plane?) on a breaking wave.  I doubt if a non-breaking wave
can generate enough speed.

This gets back to Bob's objection to John's statement about surfing/
planing on a wave.  I can see that surfing can imply that you are
on a breaking wave and the forward portion of the hull is planing,
but the aft portion isn't.  This doesn't neatly fit into the definition
of planing (without specifying which definition :-).  It also 
differentiates on whether the water propulses or drags on the vessel.

Since surf around these parts is either laughable or terrifying (no 
in between on Lake Ontario or Georgian Bay), I'll leave it to the
Left Coast surf dudes to flesh this out a bit.  Kevin?, Shawn?

Mike



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