[PSUBS-MAILIST] Going faster (was: gel-coat)

["Michael B. Holt" <mholt@richmond.edu>]

Thanks, Tim, for the essay about grooves in the hull.  Somewhere
around here I have papers about that sort of thing, and there was a
patent granted for the idea of a grooved hull.  

One of the papers is about the shark and dolphin skin characteristics.
What I gleaned from the article was that dolphin skin, especially,
reduced drag by being flexible.  As I recall the paper, bubbles formed
on the skin, and the dolphin would eject them by sending a wave of
warm blood along its body while flexing the entire skin in a series 
of pulses.  The bubbles served the same function as the sandpaper, but
only up to a certain speed; beyond that, they were drag-inducers.

Of course, figuring out how to send a series of waves long the
out hull of a submarine might be an engineering challenge ...

Shark skin is different, being covered with a layer of fibers oriented 
along the flow direction.  That might work, for some speeds, but the
idea of a submarine covered in plastic fur is, at least, funny as hell.

Has anyone evdr followed up the idea of the flipper as propulsion?
There's a canoe builder in Canada who has a pedal-pwoered boat that
uses a flexible flipper for propulsion.  I'll see what I can find.


Mike