Re: [Paddlewise] Pro's and Con's of the "Swede Form"

>The subs' speed will determine the amount of
>energy to be dispersed. Unless the bottom (and sides) of the basin the sub
>is in can disperse the energy from the pressure in front of the sub it
would
>seam that it would eventually (how soon is unclear but given the
>incomressible nature of water I would think it would have to happen very
>quickly) end up at the surface and be used to lift some water above the
>level of the surface creating waves whether they be detectible or not.

For what it is worth is worth, "The modern submarine experiences no
wave-making resistance whatsoever when submerged more than three diameters
from the free surface".

(Thomas Gilmer, "Introduction to Naval Architecture", the text book for
naval architecture at the U.S. Naval Academy.)

>On the other hand maybe no wake is really necessary as the pressure at the
>bow and the lower pressure at the stern may just mean the water moves
faster
>over the hull to fill in the low pressure area behind the sub balancing
the
>system.

Most hydrodynamicists call this form resistance. Scragg and Nelson studied
form resistance on rowing shells and worte an interesting paper on this.


>Back when I was trying to understand weatherhelm I looked in a lot of
books
>and while many of them mentioned it and some even described how ships add
>funnels and such forward to compensate none of the books I found gave an
>expanation and I had to devise my own.

H. Eda has published at least ten papers on this that have provided me with
a lot of help. Also, Nomoto's "Balance of Helm of Sailing Yachts" can prove
useful and "Principles of Naval Architecture" also provides good
background.

(SNIP)

Cheers,
John Winters
Redwing Designs
Specialists in Human Powered Watercraft
http://home.ican.net/~735769/

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