Why no connected legs with monofin?

[Theodoric]

Ever since the first time I saw a monofin, I've wondered why someone hasn't tried some way of eliminating the space between the legs. They're stuck in the same position anyway, and doesn't the water just keep swishing back and forth between them? If the monofin has all that surface area and makes you move more fishlike, then why not take the fish (or underwater mammal) idea all the way?

There must be something I'm overlooking, but it seems that some kind of membrane wrapping the legs together would give more surface area for propulsion, as well as improving streamlining. The specifics would need a bit of thought, but would it work?

Forgive me if this is a dumb question, but I'm curious to know what you think.

 

[JennyWren]

I was at a pool competition this spring and Wes Lapp was there in his one-legged suit. It's a special suit he had made which has one tube for both legs. He was using it for a very specialized arms-only no-fins technique though, not for monofin swimming, although I could see that working too.

here's a pic:

Wes at the shallow end | Vancouver Apneist Freediving Club

 

[TimoP]

He was using it for a very specialized arms-only no-fins technique though, not for monofin swimming, although I could see that working too.

Do you mean that he didn't used dolphin kicks in DNF...I wonder why, if so?
How effective was the technique ?
It would be nice to see a video...

 

[efattah]

Wes uses a monosuit.

But:

#1 Monosuit is allowed in DNF only if you DO NOT do dolphin kicks. He uses only arms for 125m+

#2 Both Wes and Herbert tried Monosuit for DYF, and said it was very bad, didn't work properly.

 

[TimoP]

About Wes and his monosuit...
I found another thread with more information and pics:
http://forums.deeperblue.com/genera...new-us-freediving-record-dynamic-no-fins.html

 

[Theodoric]

Thanks a ton guys, his monosuit is exactly what I was picturing. But I'd really like to hear why it didn't work for DYF. Dolphins don't have holes in their body for the water to swish back and forth, so why doesn't it work well for people? Maybe the ankle section is still too wide?

Very interesting, though. I wonder if anyone is working on a way to make it work for DYF or CWT. Could it ever work?

 

[wes]

Hey,

Short answer is I tried it with monofin and was horrible, really horrible to kick, felt like kicking in oatmeal.

Longer answer has to do with water flow and separation drag in a dynamic motion flow field (your legs kicking back and fourth in the water) which is still outside the realm of computer modeling due to effects of shifiting vortexes which are really really hard to model. If it did work to have legs together then the ankle section would need to be super pointy like dolphins and whales have right where the tail enters the flukes like in this photo:

http://www.mundoazul.org/images/fotos/dolphin-tail.jpg

You can see where the ankles would be the tail is very narrow and quite tall with pointy ridge on top and bottom. This makes the "ankle" part of the tail very streamline to the up and down motion and making the rubber suit to go around the ankle is just the opposite.

This is also one reason I am working on suit for DNF and not Dynamic with fins as its so much simpler to do without the monofin adding complexity.

Cheers Wes

 

[TimoP]

If it did work to have legs together then the ankle section would need to be super pointy like dolphins and whales have right where the tail enters the flukes like in this photo:
http://www.mundoazul.org/images/fotos/dolphin-tail.jpg
You can see where the ankles would be the tail is very narrow and quite tall with pointy ridge on top and bottom. This makes the "ankle" part of the tail very streamline to the up and down motion and making the rubber suit to go around the ankle is just the opposite.

Thanx, very interesting, I'd never thought that this way... and the pic (of the tail of a whale) tells much.

In fact, should somebody test a quite different type of monofin with a really narrow part (made of rubber or something like that) between feet and a monofin's blade?
For reference, see that pic of a whale tail.
Or has it tested already?

Another idea:
Should legs be on top of the other, not side by side, when using a monofin in DYN?
Of course foot pockets must be so, too. If you try to put your legs so, it feels almost as easy as legs side by side. I mean from knees to toes, there is then a 0.5-0.7 m long, 0.1 -0.15 m narrow and 0.2-0.25 m tall part before monofin. These figures seems to be quite good ones, when looking that whale tail pic.

And THEN a narrow streamlined monosuit (even with pointy ridge on top and bottom) like that in the pic of a whale tail...
Probably it's a AIDA rule issue if using that kind of monosuit for monofin in a competition. But without a special monosuit, just legs one on the other and using on normal suit, should be ok in competitions, too.

And once again, it may be a different thing for freedivers than finswimmers. Finswimmers may have some problems if legs are not side by side, beacause they must use much more muscle strength than DYN freedivers. Freedivers want to be streamlined to save oxygen.

Here are some other kind of results after many years of hard researching and testing to find a streamlined shape:

If your REALLY want to save fuel, and BTW oxygen consumption of motor and CO2 emissions,
and have a 100 km long drive with 0.1 L of petrol:
http://fmmc.kapsi.fi/pics/comppics/nokia04/bs_03b_track.jpg

or even without normal fuel drive 100 km/h:
http://www.speedace.info/solar_cars..._Wing_front_Japanese_electric_powered_car.jpg
http://news.cnet.com/i/bto/20081120/SolarWolrd_Solar_Power_1_400x236.jpg
http://www.julrides.com/wp-content/uploads/2008/12/tiga-solar-powered-race-car.jpg
http://static.arstechnica.com/assets/2009/06/UMich_solar_car-thumb-640xauto-6119.jpg
http://liveearth.org/liveearth/wp-content/uploads/2009/03/img_7668_opt3.jpg

These are not much like a F1 racing car, which is done for max power and speed, not for to minimize consumption.

 

[apneaboy]

Is the video available for watching yet Wes?

Looks like a really good idea

 

[glubglub]

Hm... I was thinking about maybe not a monosuit per se, but more along thick kneepads (of course with some ergonomic feature to it so it doesn't cramp the legs) to limit my knees from bending too much on a kick!

Just an idea

P.S: Also Wes, how much weight do you use for your monosuit?