More on Underwater Gliders

ianjk writes "Abcnews.com is reporting on two underwater gliders developed by the University of Washington and Webb Research. Both use very little energy and have quite long ranges (thousands of kilometers). Of course, the US Navy is showing quite an interest in the project." We mentioned these earlier.

Comments

This will ease the Greenies pressure on the Navy

[typical geek]

One of the biggest use for these will be as weapons, count on it. And this will get the Greenies off the Navies back (at least until they find some other windmill to tilt at, like deaf whales or something).

There have been a variety of Navy programs that used trained sea mammals to protect Naval bases, for instance the trained dolphins trained to bump into a VC frogman in Kham Rhan bay, but they never told the dolphins that the bumping hat was an activated mine. Boom!, one less flipper, and one less Charlie.

There are also reports of using sea lions, seals other cetaceans to watch for submersibles and boats, and hit them, forcing a detonation. For instance, Day of the Dolphin is a thinly veiled documentary on teh CIA's attempt to train dolphins to blow up Castro's yacht.

So, with these, everyone will win. The Greenies cute little dolphins don't have to kill, and the US Navy can continue to enforce the Pax Americana, and the rest of the world (except for evildoers) can go about their business, criticizing war mongering Americans, yet profiting from the most peaceful age the world has known since the Roman Empire. We business savvy sorts call that a win-win situation.

How Deep?

[Marco_polo]

I wonder how deep these gliders will go? At what depth does the pressure start playing havoc with its sink/swim functions?

I am really curious as to what we could find if we put a bunch of these in the ocean, and just monitored for objects that don't belong..

the sunken city of atlantis? :-) but seriously.. I would love to see what kind of data a long term mapping program would compile..

Re:How Deep?

[jovlinger]

You have a couple of options. First of all, you can recover quite a bit of energy from the work performed by pressure: These devices all have sealed bladders that provide most of the bouyancy on the upslope.

However, when compressed, they will get hot, and this heat can be used to drive a sterling engine against the temperature sink of the ocean. Likewise, on rising, the bladders will cool, allowing you to drive the sterling engine in reverse, with the bladder as the sink and the ocean as a heat source.

To provide the necessary extra bouyancy to go from dive to rise, a chemical could be released into a reservoir of seawater (off hand I can't think of such a chemical: you need something which expands the volume of seawater). However, you could likely carry enough of such a chemical for many dives. To go from rise to sink, you need merely vent the cavern, fill it with sea-water, and start over again.

Re:Ridiculous

[nihilvt]

No very ridiculous. Drag force is typically proportional to the square of the velocity. This thing apparently moves at 1 knot. Reductions in speed save you quite a bit of energy, actually. Viscosity becomes a player at higher speeds.

Re:US Navy drones and DSV's

[timepilot]

I worked with a group of people at Rutgers University who used Webb gliders and other AUVs. The gliders were used very successfully in a littoral environment, often to provide dense data streams which were in turn used to initialize ocean models.

The models, which were given a very accurate representation of ocean and atmospheric conditions with this data, were used to produce forecasts of ocean conditions which could have been very useful in a littoral warfare environment.

Check out http://marine.rutgers.edu/mrs/LEO/LEO15.html

Underwater bicycle is more interesting

[Anonymous Coward]

http://www.underwaterbike.co.uk/

Solar Panels?

[cybercomm]

They said the batteres would be LiIon and that the submersible would be comming to surface to communicate, so why not add a couple of solar panels? Im sure it won't bring up the costs significantly. (Heck NASA probably already has a bulk discount on solar panels :) Does the depth and salinity in water affect solar panels; is that why they are refraining from using them?

What about infinite battery life?

[Andy Dodd]

Maybe not quite... Rechargeables decay after a while...

It looks like at least some of these designs surface periodically for a GPS fix.

Why not stick a small solar cell on the upper surface? Given the power requirements it shouldn't take too long to recharge. It can probably even recharge a meter or two (or more depending on the water clarity) down from the surface.

Re:Ridiculous - Look at history!!

[mustangdavis]

It is a well documented fact the the countries with a dominant Navy have always been the pwoer house of the world.

There is no way to fly, reload and refuel our (the U.S.) military planes and use them effectively in a war without air craft carriers .... which is why we keep a dominant Navy. They also make it possible to place embargos into effect!

As far as history ... why do you think Great Britian was the power house it was back in the day? G.B. is just a small islnad nation, but yet they were the dominant force on this planet for over a century. Why? Their NAVY!!!

Keep in mind that there is no way for any Asian or European countries to invade the Americas (if they wanted to) without the use of a Navy. A solid Navy is the key to winning ANY war (without using nukes).

Those who don't learn from history are doomed to re-live it!

Re:Interesting to watch

[Shadow2097]

What I meant was that if mini-subs are introduced, the people they're replacing (submarine crews) aren't adrenaline junkies like USAF fighter pilots. I probably should have made that more clear.

-Shadow

Inventions of Daedalus

[serutan]

Wow! The thermal version described in the article is very similar to the "glidoons" proposed in The Inventions of Daedalus a number of years ago. A glidoon is an inflatable glider containing a substance that is gaseous at sea level and condenses in the cold of high altitude. The craft glides up and down without fuel, driven only by the endlessly reversing buoyancy. Exact same principle, and they really did it!