Re: [Paddlewise] surfing and hard chines

Kevin write early on Thursday:
>>  I
> do not know exactly how far aft the hard chines and flat bottom need to
> continue in order for this performance to occur.  However my intuition
says
> that underneath and directly behind the cockpit is the critical area.  The
> stern is less important, because it is probably sticking up in the air
> anyway.

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> ??  I'm still experimenting on this
one.  Need to do an A/B on the same wave with a Pintail (pointy, soft) and
something boxy and hard.(ie. Mariner or ??)
>
> 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.
>
>
> Incidently, my next kayak project will be a skin-on-frame boat designed
> specifically for surfing wind waves on the Columbia River.  There is small
> group of paddlers in the Portland area who like to do this. Apparently the
> waves can get quite large, almost to the point where they are called
swells.

That group is growing.  where does a wave end and a swell begin?  That is
the question, grasshopper!

;-)

steve




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