Flying Underwater, A Blast From The Past

[ricki]

I am a lucky owner of the Aqueon since last year too, but unfortunately did not yet have chance to use it a lot. In fact I did only one test run in a pool, and then once in open water. I plan playing with it more this summer. I have a question for you guys, though - I had pretty hard time doing efficient immersions. Trying to get submerged took a lot of energy and time, so my down times were cut quite short due to this inability. Do you have some tips for me?

Hope you have some good times with the Aqueon. Regarding descent, I usually take a couple of longer strokes to pull myself beneath the surface. A couple of the strokes, not real strong ones in this case, show up in the first part of the clip at: [ame=http://www.youtube.com/watch?v=z-EJt_PZ6GE]YouTube - Aqueon 1[/ame]

If I am trying to make a steeper dive, I sometimes pivot one foil out of the water, sort of like doing a high attitude banking turn in an airplane. I then stroke hard spiraling downward until aligned vertically.

Tom has gone a lot deeper than I have with the Aqueon and has some experiences and observations in that regard. Cal mentioned tensioning the leading foils 180 degrees opposite the normal configuration. This would allow feet first and ideally faster and easier descent. You would need to configure for easily changing back to the normal setup for your ascent however.

Have fun and let us know how it goes,
Rick

 

[Tom Lightfoot]

If you want to go straight down, the back start seems to be the key. Lie on your back, arch your back, bend our knees and scoop the water with your hands. It's still not as easy or satisfying as a front start with conventional fin(s) but it can be relatively efficient with practice.

The advantage with line diving is that the aqueon gives you the stability and flotation to make breathing up pretty easy. If you start with your head to the float then you end up directly facing the line after the start. I've even used a lanyard without tangling myself.

Cal claims to have no trouble doing dives on his front but it's something that I have yet to master.

Glad to see another aqueon owner out there, Trux. Good luck with your machine!

Tom

 

[Tom Lightfoot]

Hi Rick,

The Dol-fin doesn't have nearly the same thrust as the Aqueon, despite having nearly the same blade size. It is also fairly unstable, at least without much practice. The Dol-fin turns easily enough but will tend to roll you over if your technique isn't perfect.

I noticed another propulsion device on your site, the Dol-fin. How was the thrust with that, did it turn fairly easily?

 

[SirScuba]

I just saw a tv show (April 2010) (discovery channel i think) where Navy combat swimmers were learning to these. the "device" was made of modern materials.

 

[ricki]

I will see if I can catch the show in a rebroadcast on the Discovery Channel. Thanks for the heads up.

Another look at DARPA's efforts to utilize the Aqueon concept. Here's the Powerswim project overview on their website:
Program Manager: LtCol John Lowell, Ph.D.

The PowerSwim program is developing highly efficient, human-powered swimming devices for use by combat and reconnaissance swimmers. This program explores a new concept in swimming propulsion that uses the same oscillating foil approach to swimming that is exhibited by many fish and aquatic birds. This propulsion approach is more than 80-percent efficient in conversion of human motions to forward propulsion. Typical recreational swim fins are no more than 15-percent efficient in their conversion of human exertion to propulsive power. This dramatic improvement in swimming efficiency will enable subsurface swimmers to move up to two times faster than is currently possible, thus improving swimmer performance, safety, and range.
Defense Sciences Office - PowerSwim

The actual inventor of this concept and over 50 years ago, Cal Gongwer hosted about four pool parties in which DARPA staff examined, used and questioned Cal at length about the Aqueon. DARPA then proceeded to consume almost $3M of tax payer dollars in the mandated creation of "new" technology. No credit or compensation has been given to Cal by DARPA in any of this. Doesn't inspire much pride or confidence in this government agency.


They even have a promotional video now:



Looks very similar to the Aqueon underwater, no real surprise there.


.

 

[Ol Dirty Diver]

Aqueon for sale:

[ame=http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=180532504596]Innerspace Corp. Aqueon underwater self-propulsion - eBay (item 180532504596 end time Jul-19-10 21:48:40 PDT)[/ame]

 

[ThomD]

Could anyone who is out there with an original wood and metal Aqueon give me a few measuments and comments on the design? Mainly it would be useful to have the wingspan and thickness and width of the propulsion foil; the point around which is pivots (appears to be a plain bearing in the nose piece); Is the mounting system whereby the bilateral elements of the propulsion foil are mounted loose (parts free to rotate out of phase) or fixed; diameter and material the joining rod is made of, like 1/2" aluminum or SS, and it's length.

I would gladly absorb as many other details as a person wanted to add, but those are the bare minimum that would speed me on my way.

I first saw this device in PM in '74. It has been in my imaginations since then, and since the internet I have come across a few references. The Youtube videos various parties have put up make it possible to start on a DIY version since the actual workings of the device weren't clear to me. Mostly whether the tether was stiff or as has been mentioned pretty much there to get the device started and in phase.

I'm by the water for the next month, with regretably light build resources, but I should be able to get something going. The main thing I lack is a piece of metal for the axle, the rest looks feasible.

I have always been interested in this device, but I could really use one at this point since I trashed an ankle, and taking the ankle flex out swimming would be great. The same accident made it really difficult to find flippers that fit, so even a fairly modestly successful Aqueon clone would be a big help.

 

[Bill]

Hi ThomD. I owned one of the first Aqueons in the early 70's. Drove out to Pasedena and picked it up from Mr. Congwer, complete with a few stories and if everything works OK I'll have another one soon.
Did you see the patent application that was published on the internet? I thought that it was on DB but I'm not sure. I think that I have a copy somewhere.
Where is TO? It used to be slang for my home town. Maybe we were in the same club 50 years ago. My memory hardly works when I go back that far.

 

[ThomD]

Bill, Toronto, Canada, though I currently live a little east of there, and am spending my summer in the Maritimes. I haven't been a member of a diving club, just self-taught starting about 45 years ago. Not a serious diver, just use it for setting up my moorings and for the fun of diving in my lake and anywhere else I might get to.

I did seem the Patent, but it didn't really clarify the questions I asked. I have my guesses, but I don't know for sure that the two parts of the foil are fixed in relation to each other, or free to pivot at both the sleeve bearing and the rod. I could scale the parts, but I don't really have to. I believe that most things of this type if they don't work satisfactorily the first time tried, can usually be corrected by the second. And I am not selling this so any improvement over flippers I can't buy or fit to my feet is going to be a plus. That said, if I can get a leg up to get a quicker start, all the better. Thanks for reading my post.

 

[Bill]

Long time since I've heard TO. Lived there from 41-59. We dove the water works at the east end and Lake Simcoe. Funny, in 69 I moved to Thousand Oaks CA and they called that TO also.
The two parts of the foil are fixed as you define it and anything more that I say will be from old memory. One pivot (rotate only) and about one inch of symmetrical camber but I think that might have been thickened for structural reasons. I'll get you some good info and any measurement that you want but it will take a few weeks.

 

[ThomD]

Thanks Bill! Just cutting up some stock today, so I will get a start but more info will be of interest as time goes by.

 

[trux]

The bottom (rear) foil is fixed (does not move at all). The upper foil rotates freelly on the metallic rod, when not attached. It is kept in the the proper working angle only by the thread and spring going from its back to the rear part. By adjusting the tension of the thread/spring you adjust also the "stiffness" of the front foil, and its maximal amplitude.

 

[efattah]

I tried Tom's Aqueon some time ago. Although I did not use it long enough to master it, I can say without doubt that the DOL-fin Orca blows everything else out of the water.

Perhaps a highly modernized Aqueon that is way lighter, and more streamlined, might compete with the DOL-Fin Orca. But it would still have maneuverability problems.

 

[trux]

Perhaps a highly modernized Aqueon that is way lighter, and more streamlined, might compete with the DOL-Fin Orca. But it would still have maneuverability problems.

Indeed, I own an Aqueon, and I believe too that the efficiency could be improved, but I found already the basic duck dive pretty exhausting, difficult, and uncomfortable with it. Sure, with training you get better, but still it is not ideal. Once under water, the maneuverability is not that bad, but I can't imagine doing a pool max DYN dive with several turns with it.

The efficiency of Aqueon is surprising, but since you have to bend your knees quite a bit, the active drag is rather strong. Also the rear foil, which serves just as a stabiliser, adds more drag as you bend your knees, since the blade gets too far from the ideal angle. In fact I believe it would be much better if the rear hydrofoil was not fixed (purely stabilizing), but movable similarly to the front foil, adding so some more propulsive force instead of just drag.

 

[Bill]

'Also the rear foil, which serves just as a stabiliser, adds more drag as you bend your knees, since the blade gets too far from the ideal angle.'
I would be interested in a comparison of the drag from Aqueon's rear foil and the drag plus reverse thrust from the front part of a mono fin Ivan. I tried to talk to Ron about it but the discussion got over my head in a hurry.
Just for the record, I would like to add one comment here. The big (brilliant?) advantage of the design is that it doesn't care how you do it but if you change the angle of the support tube in a vertical direction, it will automatically produce very efficient thrust. If you want a demonstration of what poor streamlining can do to that thrust, try using it with fins on.

P.S. Please note that I don't compare the Aqueon to the Dol-Fin Orca. No comparison for a mono fin user.

 

[trux]

I just added the results of the last CAFA competition and see that Tom Lightfoot competed in DYN and in CWT with the Aqueon! I do not know whether anyone else ever did, but the results are quite good (rather close to Tom's competition PB's in DYN), and may be well unofficial Aqueon competition records (100m DYN and 40m CWT):

APNEA.cz ranking - CAFA Western Regional Competition II 2011

I wonder how Tom managed to do the DYN turns - in a pool with shallow ends it may be quite challanging with the Aqueon.

 

[trux]

Just got some new details about Tom's performances with the Aqueon: the DYN swim was in a 25m pool with the ends 120 cm deep! It must have been pretty challenging since the rear rigid blade is exactly 120 cm wide too! Additionally, the fin is quite heavy, it means all those turns certainly cost Tom quite a bit of energy.

 

[Bill]

Did you crank into your thinking Natalia and Ron's performance at the world's?
I bought my second Aqueon (the first one was stolen in '74) and am waiting for the perfect time to spend a day in nostalgia.

 

[trux]

Yes, Bill, I have no doubt the hydrofoil principle is a superior technology, but the DOL-fin is almost half a century more modern fin than the Aqueon, and hence it is also much lighter, smaller and especially far not as wide, so the excellent performances of Natalia and Ron are not that surprising. I have an Aqueon too, but frankly told I never thought I could try any competition performance with it. Now I see it is worth of reconsidering

 

[ricki]

Thank you for passing this along Trux. It would be good hear hear Tom's impressions about competing with an Aqueon. I believe this is a first using the device. I will give Cal a call, he will enjoy hearing out it.