[Paddlewise] Rudders redux

Matt wrote in response to Richard Culpepper;

>Show me the evidence!

This is good advice. So much of this debate hinges on faulty logic, opinion, 
specious arguments and flawed "research".

I know Matt won't mind my using his post as an example since I know he 
welcomes constructive criticism and won't take it personally. As I pointed 
out in  a previous post some of Matt's arguments lacked objective support 
(3,4,7,12,14 and16),  some used specious logic (1,2,5,8,9,13,and 15) and 
some used flawed data (6). Suitable objective testing to support these 
arguments would go a long way and be enormously useful.

The important thing is to recognise that a poorly designed or built rudder 
is not a suitble foundation for their condemnation.

Of course, the opposing side isn't any better. Paul Caffyn is a good story 
but his story is anecdotal and only applies to him and his particular 
experience. It is certainly not a universal recommendation for rudders. 
Obviously the personal preferences of paddlers are just that - personal, 
and most arguments in favour of rudders hinge on personal preference. Like 
the opposing view they lack objective support.

However, because there is so much support for Richard's points they are 
useful. Most designers of sprint kayaks actually do the research (although 
they are not keen to publish it for obvious reasons), have done tank testing 
and controlled real life testing and have found that there is a net 
improvement in performance using a rudder. Experience in the hotbed of 
competition supports this. Of course, as Matt points out, the seem specific 
to one type of boat in very specific conditions. It would be good to have 
data that crossed those boundaries. One of the things that is not mentioned 
when comparing rudders vs heeling is that, while the rudder adds resistance 
so does heeling the boat. The heeled boat changes shape and form parameters 
and not usually to the benefit of resistance. The amount of added resistance 
varies considerably from boat to boat but it exists and is measureable. 
Unfortunately, Sea Kayaker did not test their kayaks heeled like we do when 
testing sailboats. It would also be nice if we could actually measure the 
added effort needed to keep a boat on course with a paddle and by leaning. 
Then we could put that part of this debate to rest.

In the meantime I suppose this kind of inconclusive discussion does prompt 
people to think about what they might want in a kayak. For me no rudder is 
the best rudder but some of my friends consider me a Luddite and they may be 
right. :-)

Cheers

John Winters
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