[Paddlewise] Rudders redux

Matt wrote;


>  Please show me point by point why I am wrong or
> being illogical.

I did this in my post of 6/25/2007 where I asked for answers to questions 
that Matt may have not considered.

Specious means: apparently right or proper : superficially fair, just, or 
correct but not so in reality : appearing well at first view. (Merriam 
Webster Unabridged Dictionary)

Item 1) You concluded that  there was less fatigue when not using rudders. 
It sounded excellent but contained no objective support just your opinion 
but was stated as if it were a fact. I am giving you the benefit of the 
doubt by treating it as specious logic rather than a deliberate attempt to 
falsely state as factual what is just opinion.

Item 2) You comment on an injury giving the impression that rudders cause 
injury when in fact, the problem was with the builder. This sounds good. One 
reads it and says, "Yes, I have seen those bare wires." It sounds good but 
is false logic That builders build poorly is not a condemnation of rudders 
it is a condemnation of builders.

Item 5) You comment on maintenance and use the words "far more". In so doing 
you suggest a quantity that sounds serious without explaining why it is a 
problem. Do paddlers not have time to maintain their boats? Can they not 
learn how? If they are unwilling to learn is it the rudder's fault? The 
comments sounded good and to the reader might make sense but they are only 
superficial.

Item 8) You comment on slower turns and it sounds good coming from someone 
of your expertise but you neglected to mention that one is not obligated to 
use the rudder for all turns or even any turns. Your comment sounds good but 
it neglects the many other options available to the person using a rudder to 
augment his abilities.

Item 9) You discuss slower spins. See above. Are spins even an issue for all 
paddlers or even most paddler? It sounds important coming from you but is it 
really? To conclude that it is requires some support or it is simply 
specious.

Item 13) You comment on rudders flopping from side to side when backing up. 
Once again, coming from you this sounds important but is it? It may be to 
some people but to how many? How often?

Item 15) You comment on the time delay in getting rudders to operate as if 
this is a failing suggesting that people using their paddles do not have the 
same problem or even how much delay is important. All despite many comments 
here from people telling how they use the rudder to adjust directional trim 
where time delay is of no consequence. Once again, coming from you your 
comments sounds impressive and convincing.

When Matt writes something it always sounds good as he writes well and he 
writes convincingly. People are likely to accept what he says thinking there 
is more to it than just his opinion or that it is based on verifiable 
testing. By verifiable I mean that anyone can perform the same test and get 
the same results. If  the test aren't verifiable one has to ask, "How 
valuable is this tests if only Matt can do them?" Is Matt the paddling 
standard? I don't Matt thinks so.

Matt has done a lot of testing and I think it is interesting stuff. However, 
one has to look at it critically. What has he missed? What is he measuring? 
Is the same for all paddlers or just for Matt?

We are flooded with claims these days that have proven specious. Claims for 
the value of drugs, safety devices, teaching techniques, strength etc. etch. 
etc. We should always be asking questions. If you will note my post of 
6/25/2007 you will note that I asked a lot of questions for which I have 
gotten no answers. Matt wants answers. So do I. If paddling without a rudder 
uses less energy (and it may) then were is the data? Did Matt do tank 
testing of heeled kayaks to see how much added resistance heeling caused? I 
haven't seen it.


Failings of Sea Kayaker rudder tests.

1. No data on the shape parameters I.E. aspect ratio, section shape, area, 
surface condition, edge shapes. This is poor practice. Without knowing what 
was tested one cannot determine the value of the tests. All we get are your 
claims that rudders can cause 10% greater drag. Does it apply to all 
rudders, some rudders, only one rudder?

2. No comparison between the resistance tests and that of calculated values. 
For example flat plate drag is easily calculated (see Hoerner "Fluid Drag" 
or most any text on fluid drag) and yet this was not done to determine if 
there might have been test anomalies..

3. If I recall correctly you once wrote that the rudder was allowed to move 
freely. This is poor test practice unless the rudder is allowed to move 
freely in use and is not controlled.

4. Insufficient number of tests over a full range of speeds. You will recall 
they tested the boats over a wider range of speeds. Why no the rudder over a 
wider range of speeds. We paddle over a wide range of speeds.

5. Lack of comparative tests to determine of the rudder was properly sized 
for the job. If the rudder was too large for the job then it has little 
meaning to people using properly sized rudders.

Actually I think I have written all this before on either Paddlewise or 
Wavelength.


Craig wrote about empiricism.

Empiricism is good stuff unless you are quantifying data. The issues here 
often have to do with quantification.  See "Perceived Exertion" by Noble and 
Robertson to learn about human failings in detecting and quantifying effort.

Imagine this. You are in the butcher shop and say you want 10 pounds of 
prime Black Angus beef. The butcher takes a piece of beef , throws it on the 
counter, wraps it and asks for your credit card. You are indignant. "Aren't 
you going to weight it. How do I know it weighs ten pounds?" The butcher 
replies, "I been cutting beef for forty years. I know ten pounds when I pick 
it up." Are you will to accept this and pay up? Think about this for 
anything that involves measurements for any force.

If so, I have some light weight kayaks to sell you. :-)

Measurements keep us honest but they also keep us from being mistaken.

Cheers

John Winters
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