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From: (no name) (no email)
Date: Wed Mar 26 2008 - 16:34:44 EDT
Boaters in the Virgin Islands should not be surprised to see unmanned winged
green torpedoes cruising slowly under the waves. They are not some new super
secret military weapon but ocean temperature sampling probes developed by
scientists at the Woods Hole Oceanographic Institute. What is most interesting is
that the probes, called thermal gliders, can travel indefinitely in warmer
waters without using any fuel. The gliders are ballasted so that they have a bit
less than neutral buoyancy. In the warm waters near the ocean surface the
glider captures and stores heat energy raising the pressure in an internal oil
storage bladder. Then as it sinks into cooler deeper waters, the increase in
pressure is used to push oil from the internal bladder to an external bladder. This
increases the buoyancy of the glider and it slowly rises, gliding forward on
its stubby wings. When the glider cools, the oil returns to the inner bladder.
As long as there is a temperature difference between the surface and the
waters a few dozen feet below the surface, the gliders will continue to move
forward. An external rudder controls direction. An equatorial circumnavigation
would be possible if wasn't for those pesky continents in the way.
An antenna radios temperature and position information to a collection site.
Navigation is by GPS and microcomputer. Batteries in the unit are necessary
only for the electronics but the next generation will have a few solar power
cells and be entirely independent.
While this solar power scheme is currently impractical for trawlers, one can
envision a brace of these small torpedoes harnessed to a boat hull, pulling it
slowly through tropic waters like a maritime coach and four. But next I
suppose that drug runners will co-opt the idea to evade USCG patrol boats.
Larry Z
**************
Create a Home Theater Like the Pros. Watch the video on
AOL Home.
(http://home.aol.com/diy/home-improvement-eric-stromer?video=15?ncid=aolhom00030000000001)
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