Re:[Paddlewise] Rudders redux

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

John wrote:
>>>>>I did this in my post of 6/25/2007 where I asked for answers to
questions that Matt may have not considered.<<<<<<<
Later in the same e-mail John wrote: 
>>>>>>>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.<<<<<<<<<

I can't find this e-mail you mentioned in checking every digest back to
6/16/07. Did the digest skip it? Perhaps you got no response because nobody
received it? Could you send a copy to me? Digests are very mixed up and have
been for a long time. Often I get responses in digests before the original
post shows up in a later digest. Within the same digest the order often
seems reversed. Sometimes a week or so that goes by between digests and I
wonder if somehow I've been dropped from the Paddlewise list. Lately the
digests contain only one or two e-mails and so I might as well not be on the
digest. This is very frustrating. I've mentioned this several times but have
been told things were now working okay. They aren't working well for me. Are
any other digest readers having this problem?

>>>>>>>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.<<<<<<<<<<

Yes, my opinion based on the extra drag due to most rudders and my racing
experience. I attributed this to using more and larger muscles to share the
drag load because of solid foot pedals to push against. Certainly a good
design could solve the mushy or sliding pedals problem with rudders (or with
many other criticisms I might have with the rudders I have experienced). I
understand John may want to focus on differences using the best possible
rudder system for comparisons and I agree that would be the ideal, but I
haven't found any of those in the real world, where my experience has been.

>>>>>>>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.<<<<<<<<<

Show me (or tell me about) this ideal rudder that is no more likely to cause
injury than the naked stern!

>>>>>>>>>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.<<<<<<<<<<

Ask any rental shop what part of a kayak requires the most maintenance and
you will hear about rudders (and maybe adjustable skegs). The one of the
owners of the rental shop next to where my shop was located, NWOC, told me
that they spent far more time maintaining rudders on their boats than all
other maintenance put together (and not all their kayaks had rudders. I
didn't say they couldn't be maintained just that far more maintenance was
required on a kayak because of the rudder. In the real world though many
paddlers don't maintain them (oftentimes even those who know better) until
forced to do so by a failure.

>>>>>>>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.<<<<<<<

The only option I can think of right now is to lift the rudder out of the
water. That takes some time as well, likely more time than that would be
lost using the rudder. I'm reporting the results of my tests. They show that
someone with good turning skills will likely find they can turn a kayak with
the rudder up quicker than with the rudder down more than visa versa. It of
course depend a lot on the kayak. I imagine that most who are rudder
dependant will find just the opposite if they do their own tests.

>>>>>>>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.<<<<<<<

Spin time is not nearly as important to me as turning time at speed but it
certainly could be in some situations. Imagine you are in a narrow sea cave
and waves are breaking as they rush in to where you are. You may be okay
facing away from them but would more likely want to face directly into them
both because you can see them coming and it will be a lot easier getting out
of the cave paddling forward. Backing out of the twisting channel will be
hard but youve found a place just wide enough to get turned around in. Of
course, you will have a limited time to do so between the waves. My advice
would be to get that rudder out of the water before attempting the turn
since my data shows the rudder slows the spin speed significantly in most
kayaks. Of course, just being there the rudder makes the boat several inches
longer and therefore harder to turn in a very tight space. Also, I've seen
several rudders (and have heard of several more) that were broken (or broke
the back of the boat--where the rudder pin levered it open) when the rudder
was slammed into rock. So, up or down, the rudder is likely a negative in
that situation.

>>>>>>>>>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?<<<<<<<<<<

Some reasons are more important than others and more important for some
paddlers than others. I certainly can't think of a time when the rudder
would be an advantage backing up and I've experienced times when it has been
difficult to do so with the rudder down. This is not a major problem unless
one is trying to use the rudder when exiting through surf and gets back
surfed. Then it is almost sure to result in damage to the rudder or stern.

>>>>>>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.<<<<<<<<<

My problem with this feedback delay is the fine control I lose because of
it. I might improve with practice but I doubt I could get as good with it as
without it.

>>>>>>>>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?<<<<<<<<<<<

One should always question authority. Even ones own. I do happen to be the
paddling standard, for me at least. I suggest others do try their own
testing using actual measurements and use those results as a benchmark and
as a guide to improving their skills and/or choice of kayak.


>>>>>>>>>>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.<<<<<<<<<<<

Having been raised listnening to TV commercials and reading advertising I've
become an automatic skeptic. When Bill Clinton said "I did not have sexual
relations with that woman....." I turned to my girlfriend and said: He got a
blow-job. Then we looked up the definition of "sexual relations" in the
dictionary. At one job by bow called me Mr. Negative because I'm always
looking for the alternate explanation that might also fit the data
presented. I can't seem to help it. Even if I wanted to I don't think I
could control my thoughts.


>>>>>>>>>>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?<<<<<<<<<<<<

Of course, it applies to only the rudder tested I've never claimed
otherwise. I would have loved to get more data, I tried, but I couldn't even
get them to test the rudder at all (or a scratched up hull with a new
one--and I had the scratched up hull with me as I was dropping it off for
the paddling tests that day--it later became the head testers kayak, last I
heard a few years ago he was still using it though the tests were done over
20 years ago). The guys running the test facility did the extra rudder tests
for free the next day because they became curious. John Dowd, who was paying
the bill told me that they weren't there to learn anything, just to compare
kayak models. I thought that was a shame because there we were with such a
good opportunity to learn something else. But he who pays the piper calls
the tune. Even at researcher rates the tests were expensive, not something I
could have afforded at the time. I've not ever seen any other data on kayak
rudder tests. If you know of any, please let me know. Unfortunately, this is
the only objective data that I know about concerning drag due to a sea kayak
rudder. I know of a guy working on a paddle that will include strain gauges.
A project I had wanted to do myself but lacked the time for. Hopefully that
will allow for testing of hulls, rudders, paddles and strokes in the real
world of offset and intermittent power application from paddling. Something
all tow tank tests can be critisized for not taking into account.

>>>>>>>>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..<<<<<<<<<<<

Repeatability is a good test for abnormalities. That was done. There likely
were many factors that effected the results but this result was not a one
time fluke. They got the same result a second time and all other results
that had been repeated were apparently also within 1% of each other.

>>>>>>>>>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.<<<<<<<<<<<

Apparently the fear was that they could not fix the rudder in exactly the
right angle to be sure it wasn't cocked a little to one side so let it seek
its own position. Much time was spent getting the kayaks lined up in the
apparatus just getting the kayaks as aligned as possible before that kayaks
tests. I did not witness or video these rudder tests since I wasn't there
that second day. It is possible the rudder did flutter some but there is no
evidence of that. My experience with skegs though is that the more shaped
the skeg the more likely it is to flutter and that flat skegs rarely do so.
Since stern mounted rudders are usually free to find their own balanced
position I can't recall ever using a rudder that fluttered. Lots of more
fixed skegs I have tested fluttered though. Even if the rudder were "fixed"
there could have been enough play or flex to have allowed a flutter. A
flutter could possible have effected the results and if I had to guess it
would be in the direction of more drag but I don't know that for sure. It is
easy to attack result you don't like and the experimenter can't think of
everything.

>>>>>>>>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.<<<<<<

Money.

>>>>>>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.<<<<<<<<<

This was not a big rudder by kayak standards, it was a high aspect ratio
flat blade 3.5 to 4" wide and maybe 6 or 8" into the water.


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/
***************************************************************************