Re: [Paddlewise] surfing and hard chines

----- Original Message -----
From: "Steve Scherrer" <Flatpick_at_teleport.com>

>
> ahhhh yes grasshopper but when you are sliding down the wave the stern is
> actually well buried in the pile and IMHO very important.  Won't the edges
> and volume aft either keep the stern floating <boxy stern> or let it sink
> into the pile <rounded, pointy stern> ??

Steve,
I'm not sure we're envisioning the same scenario.  I am talking about
smaller wind waves, with no pile.  Also I describe correcting a broach once
it has started, but while the boat is still pointing forward down the wave.
The boat has not fully broached, but is only 30 degrees or so off course
from straight down the wave.  At this angle, most sea kayaks (and indeed
most paddlers) are beyond the point of no return in terms of preventing the
broach.  I was surprised to find that I was able to recover from this point
in the broach, and continue on surfing the same wave.

But back to your question, I really don't think the last 2-3 feet of the
stern has much impact while the boat is only 30 degrees off course and into
the broach.  Often times it will be out of the water, and when it does hit
the water, it will act to correct the broach, not enhance it.  So in this
case, a sharp, pointy stern would help.  But again, this effect is much less
important than the ability of the amidships hull to break free from the wave
while the paddler to gives a HARD rudder stroke and maintains the proper
edging angle of the kayak.


> >
> > One thing that whitewater boat designers have learned is that the chine
> > needs to be really sharp for flat spinning.  Soft hard chines just don't
> > work, so boats like Mariners with their softly defined chine would
likely
> > have some trouble in this maneuver.  Note, I am trying to make a
> distinction
> > between the rounded chines and less-sharp hard chines (e.g. soft).
>
> yeah but with the ww boats they are gaining sooooo much wetted surface
with
> the *planeability* of a crisp, flat edge.  With a sea boat you need to hit
a
> compromise.
> >

Yep, the knock against my Arctic Tern is that it is a little slower than a
round-hull boat due to the extra wetted surface area of the crisp hard
chine.  I'll take a 5% reduction in cruising speed any day for maximizing
rough water and surfing performance!

Incidently, it is my theory that whitewater boats need wide flat hulls with
lots of wetted surface area because of the paddler's inability to hold a
boat perfectly flat to the wave's local surface.  This is a crutch for
non-pro paddlers like me.  A 23" wide flat bottom rodeo boat would spin just
as well a 26" boat if the paddler is good enough.  However a wider boat is
probably an enhancement for balanced volume distribution during
cartwheeling, and hence we'll never see a supper skinny rodeo boat (only
squirt boats).

You're going to add me to the email list for Columbia River surf mongrels,
right?

Cheers,
Kevin


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