Re: [Paddlewise] Rudders redux

Richard wrote:

>>>>>>>>>I prefer a footboard with a steering stick rather than foot pedals.
The footboard makes for better use of the legs during the forward stroke (as
in sprint boat racing).  For messing about in the surf where pitonning is
possible, I am concerned that pedals may permit one's feet to slip past the
pedals and become entraped (which is why many wild water kayak designs moved
away from small foot pedals fifteen or so years ago).<<<<<<<<<<

Earlier kayaks (including Olympic kayaks) used a rigid bar as a footrest.
They were found to be dangerous for the reason Richard stated, ones feet
could get slammed past them by a sudden stop and not easily come back out.
That hazard resulted in "fail-safe" bars that had a slot in one side that
would allow the bar to swing back and open up if pushed from the back side.
Many foot pedals are also built to ratchet back if a foot (or feet) goes
beyond them and the pedal is in the way of withdrawing it/them (or shoelaces
or sandals hang up on it). The bars used on many Olympic kayaks are mainly
bars with a slot in them for the steering stick to move back and forth in.
Are they fail-safe? Of course not many would find themselves doing enders in
surf and if they did the whole boat might explode around the paddler anyway.

Richard wrote further:
>>>>>>>While a rudder is not necessary for steering control, it sure helps
(particularly in quartering winds).  Yes, it adds a bit of drag, but it also
permits you to spend your efforts entirely on your forward stroke, rather
than using part of your efforts to steer the boat.  I don't have any stats
to put forward on this, but for the last couple of decades I have paddled
sprint kayaks with rudders (they all have rudders -- which is worth noting,
for if rudders were not a good thing then Olympic racers would not use them)
and identical sprint kayaks with their rudders broken off, and I can assure
you that even in calm water and calm wind condtions, sprint kayaks with
rudders go a lot faster than their identical counterparts without
rudders.<<<<<<<<<<<

A lot faster? Just how much faster? Who has done these tests? Where are
these results reported? There are other reasons than straight ahead speed on
calm water that may be the reasons that these kayaks have rudders. Let me
suggest some.
1) The possibility of side winds. Olympic kayaks are strong weatherhelming
kayaks for several reasons. Even if the kayak was a hair faster without the
rudder the weatherhelm caused by a little side wind would result in harder
strokes needed on one side than the other. A narrow rounded (minimum wetted
surface) kayak hull (built for just top speed) does not steer well with a
little tilt because the underwater shape doesn't change much by doing so. If
the races were run indoors and only one kayak at a time in perfectly calm
water, the non rudder kayak might have a chance of being faster. If you want
to see which is really faster that would have to be the test criteria. 2)
However, since they don't race one at a time, everybody in the race besides
the leader may have to deal with the divergent bow waves from the boat(s)
ahead. These waves (made by another kayak of the same length pushing hull
speed) are of just about the worst possible length for causing broaching and
they become quartering seas for the following kayaks (about the worst
possible angle to cause broaching). This alone would make a rudder necessary
in such a rounded hull. Even if the comparisons were done indoors in calm
water one at a time the rudder boat might win. 3) To minimize wetted surfave
the hull is rounded and rockered some. The rudder adds some wetted surface
some but if it allows a boat that might otherwise wander due to its
one-purpose hull shape it might well be worth it rather than adding more
keel (and thus also more wetted surface friction) to the hull to get it to
track better. I suspect that under these conditions the results are likely
to be a very slight difference. I wouldn't bet much either way. Show me the
evidence!

Matt Broze
www.marinerkayaks.com  
***************************************************************************
PaddleWise Paddling Mailing List - Any opinions or suggestions expressed
here are solely those of the writer(s). You must assume the entire
responsibility for reliance upon them. All postings copyright the author.
Submissions:     PaddleWise_at_PaddleWise.net
Subscriptions:   PaddleWise-request_at_PaddleWise.net
Website:         http://www.paddlewise.net/
***************************************************************************