Re: [Paddlewise] planing

Michael Daly wrote:
> In very
> general terms, semi-planing is when the boat is displacing less
> than the maximum and planing is when it reaches maximum.  Trim
> changes as well and the nature of resistance changes from wave
> and skin friction dominated to spray and skin friction dominated.
> None of this defines planing, but describes its behavior.
> 
> But remember, the real issue is not what planing is, but what the
> difference between planing and surfing is.  I think most folks
> can accept the definition of planing.  They've been talking around
> it for a while.

Agreed, and I think all the definitions given for planing have been
essentially equivalent with the exception of specifying exactly where
the transition zone begins and ends.
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.

Given these definitions, a kayak could be
1) neither surfing nor planing (the most common situation)
2) surfing but not planing (typ. because the speed is not sufficient to
plane)
3) planing but not surfing (usu. needs a sail or a towline)
4) both planing and surfing.

My disagreement with John's statement was not that he distinguished
between planing and surfing but because I felt he implied that condition
4) could not exist.
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