Follow Slashdot stories on Twitter

 



Forgot your password?
typodupeerror
Robotics Science Technology

DARPA Develops Dolphin-like Tail For Divers 146

Posted by Zonk
from the chimera-tech dept.
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.'"
This discussion has been archived. No new comments can be posted.

DARPA Develops Dolphin-like Tail For Divers

Comments Filter:
  • by MichaelSmith (789609) on Saturday August 11, 2007 @06:22PM (#20198737) Homepage Journal

    But it reminds me of this gadget I saw on TV somewhere. Its like a bicycle for travelling on water. It has the same two submerged wings but the rider sits above the water and pounds the machine up and down to keep moving (and dry).

    This is a beautiful device. Short cord wings are always better once the materials are up to the job.

    • by rben (542324) on Sunday August 12, 2007 @04:49AM (#20201617) Homepage
      So DARPA has developed the AQUEON, http://www.abc.net.au/tv/newinventors/txt/s1106609 .htm [abc.net.au] , which was actually developed by an Australian in the 70's? Got to make you wonder why no one in our government every checks to see if they are giving out grants for developing stuff that's already been patented. I wonder how much we paid to "develop" something that was probably taken from the original inventor's patent drawings. Sounds like there wasn't much actual development work done, to me. I wonder how big the grant was.
      • Oops your home page is crashing. Missing something called functions.inc

        I should have recognised that video from The Inventors because I watched it a lot in the 1970's. Even if this DARPA team started with that invention they would still have had to do some development work, probably using better materials and working out how to validate and maintain the product. Anyway, thanks for pointing that out.

      • Earlleir than that (Score:2, Informative)

        by Muchsake (769101)
        Not sure exactly when but I watched an article about this on Tomorrows World a BBC science program sometime between May 1965 and September 1967 (That was the period that my family were based in Northwood. I know it was then because I wanted one and tried to make my own in the workshop that house had).
  • Man From Atlantis? (Score:3, Interesting)

    by Picass0 (147474) on Saturday August 11, 2007 @06:33PM (#20198817) Homepage Journal
    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?

  • RTFA (Score:4, Funny)

    by Anonymous Coward on Saturday August 11, 2007 @06:44PM (#20198869)
    No need to click and read the article. The summary *is* the article.
     
  • now, (Score:3, Funny)

    by martinelli (1082609) on Saturday August 11, 2007 @06:46PM (#20198881) Homepage
    we just need some laser beams.
  • by Firethorn (177587) on Saturday August 11, 2007 @06:54PM (#20198919) Homepage Journal
    come up with a budget version, the $500 price-tag is going to keep me firmly in my flippers.'"

    Personally, I think that a $500 price tag will result in this gaining widespread use, assuming it's as useful as the article states.

    Why? People spend more than $500 all the time on bicycles, surfboards, skis, and other athletic equipment all the time. Matter of fact, I wouldn't be surprised if all the equipment for your typical diver exceeds $2k. A quick search shows new surfboards costing $300-400.

    Worst case, it can be rented out to various tourists at $10/day and pay themselves off in well under a year.
    • by Anonymous Coward on Saturday August 11, 2007 @07:10PM (#20198971)
      Its not uncommon for people to spend $120-$150 on normal fins for scuba diving. Some free diving (holding your breath and swimming to depth) fins can go for over $200. The Omer Millennium Carbon Rekord III has a MSRP of $504 (this sells for $420 online).

      So I'd think that a $500 fin if useful could have quite a market. Recreational divers would probably just use underwater scooters if they really needed to go a great distance from their entry point so I'm not sure how hot they'd be on having to kick it themselves. 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.
      • Re: (Score:3, Interesting)

        by Firethorn (177587)
        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
      • by aaarrrgggh (9205)
        $500 is perfectly reasonable, agreed. But the underwater scooters are hard on air consumption (you have to hold on tight and maintain leg stiffness for proper control). If the super fin works well both for high speed and low speed motion, it sounds like a winner.

        Personally, I'll stick with my Quattros. Scuba diving is all about moving as little as possible... but having the extra power when you have to fight a current.
    • by yfarren (159985)
      2 knots an hour? for 300 m? I can do that with my legs....
      • Re: (Score:3, Informative)

        by gujo-odori (473191)
        To put the speed in perspective, 2 knots/hours is roughly double the speed of the world record holder in the men's long course 800 meter freestyle. Even allowing for fins, and for being under water, I rather doubt you could swim that far, that fast, with your legs.

        Plus, of course, if a person could swim that far, that fast, with their legs do you really think DARPA would have spent the money do develop this device?
      • Re: (Score:3, Interesting)

        by Firethorn (177587)
        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.
      • by danlock4 (1026420)
        2 knots = 2 nautical miles per hour = 2.3 mph = 3.7 kph
      • 2 knots an hour? for 300 m? I can do that with my legs....

        Of course you can. The device is strapped to your legs after all.
      • Re: (Score:3, Funny)

        by geobeck (924637)

        2 knots an hour? for 300 m?

        That's a hell of a distance over which to sustain that degree of acceleration. ;)

        • by vrt3 (62368)
          On the contrary, I think it's not easy to accelerate that slowly: 2 knots an hour is only 0.000285802 m/s^2.

          If you start from zero speed and accelerate with uniform acceleration of 2 knots an hour, it takes you just over 24 minutes to cover 300 m. The speed at the end will be 0.414 m/s = 1.49 km/h = 0.80 knots. Nothing spectacular.
    • But, all those things you listed are necessary for their respective activities. You can't ski without skis or surf without a surfboard.

      However, you *can* swim underwater without the Powerswim. How much more effective is the Powerswim than ordinary flippers? Is it worth the $490 increase in price?

      Or if you want to go faster, you can spend $150 to buy a motorized waterscooter that goes 3 times faster than the Powerswim.

      Obviously I've never Powerswimmed so I don't know how great it is, but it would have to be
      • by Firethorn (177587)
        But, all those things you listed are necessary for their respective activities. You can't ski without skis or surf without a surfboard.

        Golf clubs? Monogrammed golf balls? Bowling Balls? Basketball shoes? MP3 players(and impact resistant CD players before that), treadmills, stationary bikes, etc...

        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, loo
        • Re: (Score:3, Interesting)

          by MichaelSmith (789609)

          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.

      • by Bluesman (104513)
        Have you ever been to California? People out here will spend thousands on any ineffective new sporting equipment that will make them look even slightly more ridiculous than the previous fad.

        Mountain unicycling comes to mind. Yes, it exists.
        • Please tell me that's an LA thing!
          Here in NorCal we would normally expect that from San Francisco, but on those streets it would be suicide, if not from the hills, then from the cars (specifically their drivers).

          On a side note, I've always wanted to line up a jump from Van Ness over the last bit of obstacles and into the bay and do it on rollerblades...
          Again, suicide...
    • by malkavian (9512) on Saturday August 11, 2007 @08:05PM (#20199265) Homepage
      I'm a diver, and I'd shell out $500 for a pair.. And yep, my diving kit exceeds 2k. Double that and you start to be in the right area.
      Fins are one of the areas that I'd love to be able to get more power from without increasing my fatigue. If someone comes up with a way of doubling my speed, while keeping my air consumption constant, I'd leap at it.
      While you're under water, everything you carry keeps you alive, and fins, often forgotten, are critical in keeping you effective in a current. There's been the odd time or two, when I've been caught in an unexpected stream, and being forced to cling to rocks to stop myself being pushed either off course (bad) or down (worse). At times like that, when being faced with a downdraught to 70m or more, you'd gladly pay all you had, and more, just to give yourself the best chance of surviving the dive. Sadly, you don't get the option when the most need it; you have to pay in advance, and hope you never need it..

      On the fun side, it'll double your range if you get twice the speed, with no increased air consumption. That means more to see with each dive. Not sure you can do a wreck penetration with one of those on you though. Too much opportunity for it to snarl, and kick up the silt. And one thing you don't want is to be stuck inside a wreck, and have the world go dark (yes, you can get zero visibility quite easily from a badly executed fin kick or two in silty conditions).

      • I've only dove once, but it seems to me that once you're inside the wreck, there's very little need for increased swim speed. Use these to get to and from the wreck, and leave them "parked" outside while you explore.
        • by aaarrrgggh (9205)
          Not all diving is in wrecks... but in a wreck you want something that doesn't create too much vertical turbulence, which will stir up silt. Curious how this would do there...
        • by malkavian (9512)

          That's what you use DPVs [wikipedia.org] for (though Widipedia has a very military looking one; This is the one I use [seadooseascooter.com]). Being as they're battery powered, you're not too worried about drag, and you've also got your fins on at the time (for manoeuverability; you steer half with DPV direction, the rest with fins as rudders). Removing and replacing fins is a bit of a pain in the derriere at the best of times, but having to stow them on you somewhere (loads of drag, cutting down the benefits of the new fins), then changing out

    • Personally, I think that a $500 price tag will result in this gaining widespread use, assuming it's as useful as the article states.

      I've been diving for a couple of decades and this includes rare specialties where covering a lot of distance is useful. For normal recreational diving traveling around fast generally indicates a newbie. The point of diving is to enjoy the scenery and as divers become more experienced they generally slow down and become "lazy" and try to leverage currents and surges as much
      • by Firethorn (177587)
        I've been diving for a couple of decades and this includes rare specialties where covering a lot of distance is useful. For normal recreational diving traveling around fast generally indicates a newbie. The point of diving is to enjoy the scenery and as divers become more experienced they generally slow down and become "lazy" and try to leverage currents and surges as much as possible.

        I was thinking 'the next bend of reef over distances'. Of course experienced divers are going to learn all the tricks to ma
      • by aaarrrgggh (9205)

        A dolphin kick is something that divers occasionally do with normal fins to vary muscle usage and avoid fatigue and cramps. So many of us are somewhat familiar with the general style. The problem with this style is that it is quite limited with respect to maneuverability. Divers often use their legs/fins asymmetrically or at odd angles. This far more useful than going fast.

        I was thinking the same thing... the versatility of a normal rigid fin seems nicer than a "high speed" fin. Haven't tried doing a dolph

  • by Kandenshi (832555) on Saturday August 11, 2007 @07:02PM (#20198949)
    For those of you not as comfortable with knots and meters(and with the help of google)...

    2 knots = 3.37561971 feet / second

    300 meters = 984.251969 feet

    So it's about 3.4 feet/s over 984 feet.
    Takes about 289 seconds, or 4 minutes 49 seconds.

    Honestly, that's not as fast as I'd expect from DARPA equipment. Nor does it really have great endurance. *shrug* It's cool, don't get me wrong, but it seems like it'd be a long way away from USEFUL except in very, very specialized situations. Help me out, I can't actually think of any times where you'd want something like this if it only lasts 300 meters. In the time you're strapping that to your legs I'll already have swam most of the way there at a leisurely pace(and as a bonus, I don't have some dolphin fin to remove when I arrive.
    • I can't actually think of any times where you'd want something like this if it only lasts 300 meters

      How far you go depends on the user. In general I think scuba gear has it easy on the oxygen supply side. The leg muscles which drive your fins can only use so much oxygen. By using muscles in the torso to push the wings up and down you do more work for more return and (probably) use more air.

      For me this is a bit like the difference between open pedals and clipless pedals on a bicycle. The former case has poor power transfer and performance, but doesn't load the metabolism so it is good for Your Mum to us

    • by Firethorn (177587)
      In the time you're strapping that to your legs I'll already have swam most of the way there at a leisurely pace(and as a bonus, I don't have some dolphin fin to remove when I arrive.

      What if you don't have to remove it? The article states that it was developed from studying marine mammals. They have their shape 100% of the time, and they can do all sorts of stuff. So, baring anything unusual, you shouldn't have to remove the device for the entire dive.

      If it allows the high speed as a result of increased s
    • Re: (Score:2, Insightful)

      by gujo-odori (473191)
      Very, very specialized situations? Uhh, this *is* DARPA we're talking about here, so it's pretty likely those are just the situations they had in mind.
    • Help me out, I can't actually think of any times where you'd want something like this if it only lasts 300 meters. In the time you're strapping that to your legs I'll already have swam most of the way there at a leisurely pace(and as a bonus, I don't have some dolphin fin to remove when I arrive.
      How far can you swim while holding your breath?
      • A fairly decent distance, if I've had a chance to prepare myself, and especially if I have some very low tech diver's fins. I'll grant you that I couldn't go 300 meters on one breath, but I couldn't go the 300 meters with these things anyway. I'd have to hold my breath for 5 minutes.
        If I was bobbing up for a breath every once in a while, then diving back down again these would convey some advantage certainly. The fact that they'd be doing some of the work for me means less O2 consumed and CO2 produced.
      • In my prime, after hyperventilating (not recommended for beginners), I could swim about 130 meters under water without the aid of fins. Now I'm old and not much good for anything.
        • In my prime, after hyperventilating (not recommended for beginners), I could swim about 130 meters under water without the aid of fins. Now I'm old and not much good for anything.
          Yeah, ditto here but I'm working to get it back. My best on land with no activity is holding my breath for 4:20... I haven't timed myself underwater though. I'm guessing you get your blood saturated to the point just below where you would pass out?
           
          • by fuego451 (958976)

            I'm guessing you get your blood saturated to the point just below where you would pass out?

            It depends on what you are going to do under water, e.g., a deep dive or a shallow swim. However, both of these activities can result in blackout [wikipedia.org]. I was a competitive swimmer, surfer and free diver so I was in excellent physical condition, knew my limitations and always had a buddy nearby in case it all went south.

    • Re: (Score:2, Insightful)

      by Trouvist (958280)
      Seeing as how I was a competitive swimmer in highschool and college, we would often do 100 meters in around 1:30 for warmup. Consequently, 300 meters would take 4 minutes and 30 seconds; basic swimming, not even getting out of breath. We could go THOUSANDS of meters at that pace (which is still faster than what this contraption does). So technically, this really isnt all that fast.
  • 85% efficiency (Score:3, Informative)

    by K.os023 (1093385) on Saturday August 11, 2007 @07:04PM (#20198955)
    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?
    • Interesting, but does that mean that the device is going to be 75% more difficult to use that regular fins?
      No, it means that for the same amount of energy you use getting from a-b with regular flippers, you can do ~a-b-a-(b)1/2

    • by Omnedon (701049)
      It means that you would be able to keep pace with a swimmer using conventional fins while expending far less energy or expend the same energy and get there quite a bit faster. Much like a more efficient car using less fuel for the same distance (or go faster with the same fuel use, but the police tend to frown on that).
    • 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 stu

  • It'd be cool if something like this was self-powered and could be controlled by EMG (the electric signals given off by contracting muscles), sort of like this prehensile tail that some folks made at the Telluride Neuromorphic Workshop a few years back:

    http://www.isr.umd.edu/Labs/CSSL/horiuchilab/proje cts/EMGtail/emg_tail.html [umd.edu]
  • if that isn't an oxymoron.

    I watch BFM Paris news stream and a French swimmer is one of their top athletes. As someone who knows just enough to paddle instead of sink, I find it a little macabre to see how very, very much she undulates her whole body like a whale or something.
    • by weak* (1137369)

      I watch BFM Paris news stream
      The researchers will have to rerun their fluid dynamics simulations with wine as the transport medium and make some adjustments before this will serve your needs.

      (BTW, not hating on the French--they account for half of my ancestry.)

  • They Call Him Flipper! Flipper!

    Faster than lightning!

    No one you see, is smarter than he!

    And we know Flipper

    Lives in a world full of wonder,

    Lying there under, under the sea!

    Everyone loves the King of the Sea

    Ever so kind and gentle is he....
  • What's the difference between this new gizmo and old good monofin [wikipedia.org]?
  • wait...... (Score:2, Insightful)

    As noted: 300 meters in 4.7 minutes. Uh, how many people can hold their breath for just under 5 minutes? Wait, I'll answer for you: Not even many SEALS I know can hold out that long without moving. This is really a piece of combat equipment to be used with oxygen and not for tourists OR a novilty. Swimmers already have monofins that can propel you "almost" as fast.
    • by grommit (97148)
      I guess you missed the part in the article that said it was meant for divers?
    • by rindeee (530084)
      'Uh, how many people can hold their breath for just under 5 minutes? Wait, I'll answer for you: Not even many SEALS I know can hold out that long without moving.' Ooooo...your sharp, biting whit and grasp of the obvious is striking. Though in the future you might consider SCUBA gear. And as for NAVSOC/NECC (SEALs et al), they would love to use this sort of thing with a Dräger. Know a lot of SEALs do you? Jackass.
  • by CptPicard (680154) on Saturday August 11, 2007 @07:54PM (#20199213)
    Lasers!!
  • by edwardpickman (965122) on Saturday August 11, 2007 @08:00PM (#20199243)
    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.
  • instead of posting these lame ass stories...
  • this is useful (Score:2, Insightful)

    SEALs turning into dolphins. Sounds like they're going backwards. And what do they do if it's a hot landing?
  • I'm not a jock, as you can tell because I'm posting to /. However, I do swim to lose my flab once in a while, and doing the breaststroke, which is a resting stroke, it takes me 50 minites to do a mile. That's 1.2mph (1.04 knots), which is half the speed of this thing.

    Now, sure, going twice as fast would be pretty cool, even if it's only for 300 meters, but I can probably go that fast or pretty close just by changing to the crawl stroke and wearing flippers.
    • Want to lose flab? one word: Butterfly.
      Once your cardio gets to the point that you can do one full lap without gassing, start alternating one fly one breast or back to catch your wind, then up it to 2:1, 3:1 as you gain. It was my favorite stroke till I got sidelined and fell out of shape.
      -nB
    • You forgot that swimming underwater is much much slower than swimming at the surface. Also it's much harder to use your arms (and your legs too) underwater as effectively as at the surface. Add a bunch of equipment strapped to you, and it makes things even harder. So they're probably making much larger gains with this device than what your calculations indicate.
  • That's a big deal. Even dolphins can only manage to sustain twice this speed underwater, and they're much better swimmers than humans will even be.
  • by phoenixwade (997892) on Sunday August 12, 2007 @06:38AM (#20202023)
    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.....)

  • Maybe this bionic fin should be adapted to help keep the not-quite-extinct Bajii [slashdot.org] out of trouble?
  • I just thank the Lord she didn't live to see her son as a mermaid!

    Mer-MAN! Mer-MAN!

The tree of research must from time to time be refreshed with the blood of bean counters. -- Alan Kay

Working...