Message-Id: <3.0.32.19971119083145.006deeec@peseta.ucdavis.edu>
Date: Wed, 19 Nov 1997 08:31:45 -0800
To: baidarka@lists.intelenet.net
From: John Gerlach <jdgerlach@ucdavis.edu>
Subject: Re: Skin Boat and Hard-shell
>> (SNIP)
>> This would answer such questions
>>as, is boat A more efficient than boat B on flat water, but
>>boat B more efficient in two foot waves? So strap an electric
>>motor to the bottom of the boat, add a rudder and remote
>>control and off you go. With an electric motor, you would
>>simply have to record electric current going to the motor,
>>knowing that power P = I^2 R where I is current and R is
>>hopefully constant. Even if it isn't, it shouldn't be too
>>hard to measure R at different loads and factor that in.
>>I don't know if driving the boat through the water is any
>>cheaper than driving the water past the boat as in a tank
>>test, but rigging up this sort of thing would certainly be
>>within the capabilities of your average third year engineering
>>student who might potentially want to do such a thing as
>>an independent study project. And the best part is that you
>>don't have to know any hydrodynamics to get answers.
>>Wolfgang
>
There are a variety of different ways to conduct the experiment so that the
results can be analyzed statistically depending on what are the real
questions you want to answer and the amount of resources you have to
replicate each trial. If the ultimate question is which type of
construction is more easily driven by electric power under varying
conditions given a certain load and load distribution then the electric
motor experiment is one way to do the test. However, kayaks are propelled
by humans who supply power intermittently and asymmetrically. Also, the
flexibility factor will vary even among similar construction methods.
Loading and sea conditions will also have a lot to with flexibility
dynamics too.
What would be the ultimate reason for doing the experiment? I like skin
kayaks for their aesthetics - the feeling of transcending time by being
vicariously connected to a different culture and for the feeling of
accomplishment you get by creating something beautiful from scrounged
materials.
John Gerlach