"Subhuman Project" Human Powered Submarine 103
"Inventor Ted Ciamillo and marine biologist Frank Fish (yes, that's his real name) are at work on a human-powered sub designed to cross the Atlantic. What's interesting is the highly efficient propulsion system which uses a 'tail' modeled after CAT scans of a dolphin's. From the article: 'Ciamillo and Fish say they knew they were onto something when the first prototype Lunocet, a piece of sculpted foam sandwiched between two pieces of carbon fiber, essentially swam by itself. When they released it at the bottom of a test pool, its buoyancy combined with its cambered shape generated a forward thrust that made it scoot across the tank.'"
Interesting (Score:2, Interesting)
Sounds fun (Score:3, Interesting)
But is it really any use? If it moves in a direction when started from the bottom of the tank is it actually of any practical use? presumably it's only the buoyancy action combined with it's shape that thrust it forward such that if you start it near the surface it wont do anything.
Effectively rather than forward motion, does this only offer diagonal upwards motion? i.e. can it work without being started some distance below the surface?
I'm not sure crossing the atlantic would be that fun if you have to be dragged to the ocean floor repeatedly and launched diagonally upwards in the general direction.
Not Entirely Human (Score:5, Interesting)
So, it looks like they'll be supplementing human power with wind power. That's kind of disappointing.
'Ciamillo and Fish say they knew they were onto something when the first prototype Lunocet, a piece of sculpted foam sandwiched between two pieces of carbon fiber, essentially swam by itself.
Yes, that's called gliding. It happens whenever a thin flat surface moves freely through a fluid. Aeroplanes and gliders use this all the time. The keel on a sailboat and the rudder on a ship use the same principle. Many autonomous underwater vehicles use buoyancy gliding as a method of propulsion. Increase the density of the robot by compressing an air bladder, and the robot sinks. Fins convert the vertical drop into a forward glide. Expand the air bladder, the robot gets less dense and rises. Again the fins convert the vertical motion into forward motion.
Re:Uh oh. (Score:3, Interesting)
What I first thought of, looking at the pix, was that we'd use this to scientifically test for the presence of really big sharks. Good luck out there, buddy.
Re:A "sub" that goes 2 meters down, and stays ther (Score:3, Interesting)
When I was a kid I used to buy these little delta winged Styrofoam airplanes at the dime store. The were meant to be launched via a rubber band and a small tab on their underside. However I used to play with them in my grandfather's pool instead. I'd go down to the bottom in the deep end, flip the "plane" upside down, and release. Result? It traveled nearly the length of the pool straight as a string and fairly quickly before surfacing. It was a pretty neat discovery for me as a small child :-)
So, I too am not really too impressed by the fact that this thing moved forward when it attempted to float to the surface. I fail to see how that equates to decent propulsion performance from a tail that was modeled after a dolphin.
How time flies... (Score:3, Interesting)
It's interesting to compare this latest reincarnation of the human-powered sub to the eight-man, candle-lit Hunley [wikipedia.org] that (briefly) prowled the waters off the coast of South Carolina during the (U.S.) Civil War.
Re:Who designed this thing? (Score:3, Interesting)
What I'm curious about is how he's going to keep his skin from dissolving after being in salt water for almost two months.
Re:Diving Depth (Score:3, Interesting)
US Navy Diver Charts say something to the effect of 'don't worry about decompression until you spend time below 32 feet (about 10 meters.)' Your tanks will run out of air before you've been down long enough (at 10 meters) to even consider decompression.
For the record, 32 feet is roughly 1 atmosphere of pressure. If I recall correctly (which means 'maybe'.)
If you want to know marine mammal hydrodynamics... (Score:3, Interesting)
If you want to know about marine mammal hydrodynamics, Dr. Frank E. Fish is the guy to go to. Take a look at some of his papers available for free download from Google Scholar:
http://scholar.google.co.th/scholar?hl=en&lr=&safe=off&q=FE+Fish&btnG=Search [google.co.th]
This guy has been at it for ages. He was my primary source of information for a research paper on the subject of hydrodynamics and energetics back in 2000 for a marine mammalogy class in my final year of university. Glad to see he is still at it, because his work is brilliant. There's some pretty high level physics involved (fluid mechanics is not for the faint of heart ;) ), but still worth checking out.