DARPA Develops Dolphin-like Tail For Divers

willatnewscientist writes "Forget flippers, the latest idea from the guys at DARPA is a tail-like prosthetic for divers. The (forward-facing) tail, demonstrated at DARPA Tech 2007, is designed to help a diver maintain a speed of 2 knots for up to 300 metres. 'The unpowered, carbon-fibre structure straps to a diver's shins and is used with a motion that is not unlike the way Patrick Duffy swims in The Man from Atlantis. The design is inspired by the way mammals like Seals and Dolphins swim. I caught this video of Powerswim (3.5 MB .avi) at the DARPATech 2007 gathering in Anaheim, California. It would be nice to grab one and try it out when I next head down to the beach, but unless its designers DEKA (the same people who make the Segway) come up with a budget version, the $500 price-tag is going to keep me firmly in my flippers.'"

Man From Atlantis?

[Picass0]

I guess they are expecting that you have to be old enough to remeber the show to have money to buy their products. Has anybody in the 20-something age group even seen that show?

Re:$500 - not a bad price

[Firethorn]

I did some research - human swimming speed record is 2.29 m/s, which is around double the 'More than 2 knots' quoted in the article. While unaided - Tom Jager also wasn't encumbered by air tanks and only covered 50 meters in his run.

Still, I doubt their guinea pig was a world-class swimmer or diver.

If it really does increase efficiency from 10%(tourist fins) to 85% like another poster said, I can see it being really popular among serious divers. For one thing, it's probably less intrusive than a scooter.

Re:$500 - not a bad price

[MichaelSmith]

I can go to walmart and buy a perfectly usable bike for $150, or go to a specialized bike shop and spend $2k or more for a really, really good bike. The same thing with golf clubs and bowling balls. Heck, look at archery. There's all sorts of sights and release aids that aren't strictly necessary that people willingly spend money on.

I am a bike rider and a snorkeler and this article has got me thinking about integrating some sort of power assisted snorkel with it. Swimming under water is more efficient than being on the surface, so being a metre down with fins like these would be a big advantage. You can't suck air to that depth with your lungs but it might be possible to use the motion of the rig to pump air from the surface and into a mouthpiece. Athletes already learn to synchronise breathing with body motion.

Re:$500 - not a bad price

[Firethorn]

Dude - either uncheck the AC comment or get an account. This is a good post.

Good point about the cost of normal fins. That was part of my point - $500 is relatively cheap for many forms of sporting equipment.

Not to mention that during the fun part of the dive people like to be able to go at a slow speed so they can see things so they'd need to bring normal fins too.

The way I see this operating, it'd be a lot like a more efficient type of fin. It's not like they couldn't just flip it slower if they wanted to go slower. IE if they want to look at something a little ways away, they can travel there faster with less effort. Without going back to the scooter

They may want to check with the patent office

[edwardpickman]

I'm not sure if the guy patented it but I saw the exact same setup, I believe it was in Popular Science, thirty years or more ago. Dead serious on this one. It had the same front fin arrangement. I remember photos of him testing it in a swiming pool. I think he claimed more than 2 knots but it could have been exaggerated. I seem to remember it being more like 3 or 4 knots.

You never used a Sun, I guess...

[argent]

The Sun audio device handled aLaw/Law audio directly, and since they were the Microsoft of the UNIX world everyone else's "/dev/audio" devices work the same way.

This is like finding a file in BMP or WAV format, you go "oh, that's an oldschool DOS/Windows guy who doesn't know any better"... this is what you get when oldschool Sun/UNIX guys who don't know any better release stuff. It's no biggy... chuckle and move on.

More efficient, yes, easier to use, NO

[Tmack]

Not a lot of information available, but found this http://www.darpa.gov/dso/thrusts/bio/biologically/ powerswim/index.htm/ [darpa.gov] that states that this device is 85% efficient, whereas typical recreational fins are only 10% efficient. Interesting, but does that mean that the device is going to be 75% more difficult to use that regular fins?

For the ammount of energy expended to move forward, as the other posters stated, no. It actually will take less effort to go faster, since its more efficient, thus more of your exerted power goes to moving you forward.

From a usability aspect, after watching the video of it in use, I have to say YES, it will be more difficult. Besides remembering to not extend your legs so far that the thing will hit you in the nuts, as you bring your legs back it extends down and away from you, just waiting to snag stuff on the bottom. This thing would only be good for swimming pools and open water where you have no intention of getting near the bottom.

SCUBA divers have a hard enough time as it is controling bouyancy so they can stay at a position close to the bottom without kicking up silt or breaking the delicate reefs. Having something like this just asks for trouble, and I seriously doubt any practial use for SCUBA exists. This being a DARPA project though, its more likely for military use such as covert SEAL ops requiring faster underwater swims. There it definately has potential, so long as they can shrink it down so its as small as/smaller than current fins when stowed, and can be put on/taken off just as quickly.

tm

The Aqueon did this 40 years ago!

[Traf-O-Data-Hater]

This DARPA thing appears to be nothing more than a copy of the famous Aqueon invented back in the 1960's. You can find videos of it on YouTube, and even the original patent drawings are online which you could use to build your own: http://forums.deeperblue.net/freediving-equipment/ 53592-weird-fin-long-ago.html [deeperblue.net] Just google 'Aqueon swimming device'.

It's Okay, I suppose.

[phoenixwade]

The monofin (backwards pointing) http://en.wikipedia.org/wiki/Monofin [wikipedia.org] has been around since the Soviets introduced it in the early 70's.

I can't see how this new thing will generate any more thrust, or more efficient thrust than the monofin does, and it has to suffer from the same basic flaw, you get lots of thrust, but sacrifice maneuverability. (not to mention the monofin isn't going to crack you in the nuts.....)