Super stiff bifins?

[Yogaman]

So here's a question - what are the disadvantages of getting a customized pair of bifins that are super super stiff?

I've been diving with Omer Millenium Competitions until now and although the foot-pockets aren't perfect for my feet, I really enjoy how they react and feel in the water - especially dynamics. I know they're, comparitively speaking, stiffish fins, and I feel that all I have to give them when doing a dynamic, is a quick 'tap' and if I'm weighted correctly, I can glide without doing anything for a long way before the next tap.

When i wear softer fins, I feel I'm moving my legs a whole lot more for the same/if not less distance. It just doesn't make sense to me.

So, my point/question: Surely super-stiff bifins (if they are correctly made, and are used with a less pronounced stroke) are better. Any opinions?

There's a guy here that makes excellent quality custom carbon blades, and I'm thinking of getting a pair....

 

[TRITON]

Yes...but question is how much O2 you burn when doing less kicks with stiff fins.I've tried doing kick&glide technique but my legs get tired more quickly.
On Potapljanje na dah in podvodni ribolov - novice H2O team you can find some DYN video footage(from MAD CUP 2007) of Stig,PeterP....and you can see the difference in technique.I myself prefer Peter's technique.

 

[trux]

It is not a general rule that the stiffer the fins the faster or more efficient they are. There is certain optimum, with just the right level of flexing, where the fin is most efficient, but quickly loses the efficiency if stiffer (or if the kicking technique is not adequate).

I saw it perfectly yesterday in our pool. During the warm-up I swam behind a colleague, who is very tall, and good swimmer - usually he is much faster than myself. Strangely, this time he almost stood on the spot and progressed very little. At the beginning I thought he was just joking or taking a rest, but when I approached him closer I saw he really made big effort. The style was quite funny though - the fins moved in all directions, like a falling leaf. In amazement I stood behind him watching his fight until we managed to reach the other side of pool. I almost did not need to move to follow him in the same speed - just a very gentle movement of ankles was needed to keep with his heroic effort. I then asked what happened to his fins.

He too was unsatisfied with his fins that he found too soft, so he added another layer of carbon sheet on the blades. He had the feeling that he is progressing quite well, and did not quite understand why I was laughing. So do not let you fool too much with your feelings - often you have the best style and reach the highest speed or efficiency when you feel kicking almost effortless. My kicking technique is not good at all, but in the rare occasions when I "catch the wave", I almost do not feel the fins - they are somehow in a resonance with the motion and I progress faster with less resistance.

In the same way I was completely baffled when I tried friends split fins the first time a few years ago. I considered them a big joke and a stupid gadget and laughed on my friends for falling on such stupid advertising trick and spending his money on it. When I've put them on, I was sure I do not progress at all - they felt as if I had no fins at all on my feet. Absolutely no resistance. But to my absolute amazement I've been swimming much faster and with much less effort than with my normal fins (I did not have freediving fins on that trip with me). Well, the twin-fins (or split-fins / propeller fins) are another topic (I addressed it also here), and use different flow mechanism than classical paddle fins, but they really feel extremely soft, but still propulse you quite efficiently. Though the acceleration and maneuverability are miserable, and they are not quite well suitable for freediving - at least not the models currently available on the market (I hope though that a manufacturer will once try optimizing a freediving fin with the split/propeller principle too).

So the conclusion is do not rely only on your feelings - the resistance you feel is not a sign of a good fin. Be sure to measure your times and distances, look videos of yourself swimming, and make sure you adjust optimally your kicking style to the specific fin you use.

 

[Yogaman]

Hey thanks for the input Triton and Trux!

Triton, I'm loading those videos right now - thanks looks like good stuff! Trux, I reckon that's probably a good rule: 'There is certain optimum, with just the right level of flexing, where the fin is most efficient, but quickly loses the efficiency if stiffer (or if the kicking technique is not adequate).'

I'm just scared of going with what seems to be a norm and buying softer fins and feeling like I've got a piece of spaghetti on each foot! I'm thinking more along the (wierd) lines of a monofin on each foot!

Shot for the advice...

 

[Whiskey]

Yogaman


You can also look at the following article for guidance 2005 Fin Test - Scuba Diving Magazine :t

 

[Fondueset]

I am no expert! But I have been diving with Omer Ice fins and Omer Millenium runners. My winter diving spots are deeper so I was using the runners - which are just a bit more than twice the stiffness of the ice fins. Lately I switched back to the ice fins because they expose less movement to fish - for photography. The interesting thing is it really made no difference - I completely forget I am wearing the fins. It feels like there is a pace of most effective kicking with any type of fin - also a certain level of optimal exertion for best speed/endurance during apnea and that when you find this you do not so much feel the resistance of the fin. I feel the fins most when accelerating up off the bottom. If you work too hard you get into an efficient relationship with drag vs thrust and spend energy overcoming that. A dramatic example is surface swimming - if you kick downward too hard you end up lifting your body up.

I have a dive buddy who kicks in the way Trux described - he often seems to be hanging head down in the water - going nowhere - while his legs sort of rotate and move at strange angles to one another. His technique fails to make use of opposing the fins.

 

[spaghetti]

I'm just scared of ... buying softer fins and feeling like I've got a piece of spaghetti on each foot!...

That's the way I always feel...rofl

 

[ncunuclear718]

It is not a general rule that the stiffer the fins the faster or more efficient they are. There is certain optimum, with just the right level of flexing, where the fin is most efficient, but quickly loses the efficiency if stiffer (or if the kicking technique is not adequate).

I saw it perfectly yesterday in our pool. During the warm-up I swam behind a colleague, who is very tall, and good swimmer - usually he is much faster than myself. Strangely, this time he almost stood on the spot and progressed very little. At the beginning I thought he was just joking or taking a rest, but when I approached him closer I saw he really made big effort. The style was quite funny though - the fins moved in all directions, like a falling leaf. In amazement I stood behind him watching his fight until we managed to reach the other side of pool. I almost did not need to move to follow him in the same speed - just a very gentle movement of ankles was needed to keep with his heroic effort. I then asked what happened to his fins.

He too was unsatisfied with his fins that he found too soft, so he added another layer of carbon sheet on the blades. He had the feeling that he is progressing quite well, and did not quite understand why I was laughing. So do not let you fool too much with your feelings - often you have the best style and reach the highest speed or efficiency when you feel kicking almost effortless. My kicking technique is not good at all, but in the rare occasions when I "catch the wave", I almost do not feel the fins - they are somehow in a resonance with the motion and I progress faster with less resistance.

In the same way I was completely baffled when I tried friends split fins the first time a few years ago. I considered them a big joke and a stupid gadget and laughed on my friends for falling on such stupid advertising trick and spending his money on it. When I've put them on, I was sure I do not progress at all - they felt as if I had no fins at all on my feet. Absolutely no resistance. But to my absolute amazement I've been swimming much faster and with much less effort than with my normal fins (I did not have freediving fins on that trip with me). Well, the twin-fins (or split-fins / propeller fins) are another topic (I addressed it also here), and use different flow mechanism than classical paddle fins, but they really feel extremely soft, but still propulse you quite efficiently. Though the acceleration and maneuverability are miserable, and they are not quite well suitable for freediving - at least not the models currently available on the market (I hope though that a manufacturer will once try optimizing a freediving fin with the split/propeller principle too).

So the conclusion is do not rely only on your feelings - the resistance you feel is not a sign of a good fin. Be sure to measure your times and distances, look videos of yourself swimming, and make sure you adjust optimally your kicking style to the specific fin you use.

Good point!

May I translate this article into chinese and put on my chinese forum?
I will claim you are origin author.

 

[trux]

Yes, sure, you are welcome, ncunuclear718. It's my pleasure to be quoted on a Chinese forum

BTW, I added your forum to the Freediving Media Base. But because I am not really familiar with Chinese alphabet, you may want to edit the entry and add some description, keywords, or other details. If you wish to edit the record, simply click on it, and on the yellow pop-up card, click then on the brown edit. You can add description and keywords both in Chinese and in English, if you wish. Or just Chinese is fine too.

Feel also free to add other Chinese (resp. Taiwanese) freediving websites - there are not too many of them there yet.