Looking closer to fins...

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

Externet

Contributor
Messages
176
Reaction score
43
Location
Mideast U.S.
Close examining diving fins...

In the beginning, the flat fins were the norm... the basic, fishlike apppendices. Just like a fish, that is the shape to give us propulsion.
Then they made them longer, became somewhat more flexible because of their characteristics, as cannot be always as rigid if made longer. Claimed to be the ultimate technology. Wider posed a problem, prone to collide themselves, and were not 'developed'.

Later, in another marketing trend or real look to efficiency, came the 'turbos' with three ports to channel water though them...¿?
These ports are angled in such way that the most powerful of the two strokes, straightening the knee (the knee being folded going to straight position), allowed a certain amount of water to just bypass the fin to its other side, with my doubts that could improve propulsion efficiency.
The now split type of fins can be just a trend, a marketing maneuver to make us buy the newest 'designs' with no real improvement behind them.

To my opinion, the shape and architecture of a fin has to be proven, by submiting it to a -force-in - force-out analysis on a laboratory.

If I have missed published results of such analysis, fine; but have my doubts such analysis has been done.
The keyword is efficency. Cannot see any other related to fins.
For a given leg strenght, there has to be a given resistance from the fin to be moved. My backgorunds is electronics, and that is called impedance matching in that field.

Explain: A super large fin can impart a large propulsion if the muscle strenght matches and is capable of handling it.
For weak legs, a less resistive fin will produce the matching propulsion. Example: an adult can arm-throw a baseball the longest distance; but a tennis ball (lighter) or a basketball (heavier) won't make it that far. The one that gets the farthest is not the heaviest nor the lightest; it's the one that MATCHES the arm muscles capability.

Translate that to legs and fins. There has to be a fin that produces the most efficient propulsion, and it is NOT the harder to kick nor the easiest to kick. That is the question, WHICH one has been proven to produce more trust for an average adult?

For younger or weaker swimmers, a different shape -or lenght- matches their leg strenght. OK, that is why fin manufacturers have young and adult sizes. They are fine with that . But returning to shape and flexibility , WHICH is the optimal?

WHICH shape is the optimum? Flat, ported or split, flexible or rigid, or combination of them? To make matters worse, observing 'professionals and instructors' They usually do not keep straight knees to propel themselves with the theorical (or not) straight knee-leg scissor motion, and a fin design should take that into consideration -not everyone will kick properly-

What do you think? Is it marketing? Is there any science behind it?
Miguel
 
I believe your main point was fins are ever changing in an effort by manufacturers to convince us that the newest are the best so we should rush out and get some. But the truth is, most people own 1 or 2 pairs of fins and dont rush out to get new anything except when the old something wears out, gets lost or needs replacement for one reason or another.
I only have two feet, why get 3 fins?
 
Well....the question is a good one. IS there SCIENCE behind it? Well yes, if you believe the manufacturers. But obviously, they have a stake in their claims.

I think if you ask 25 different divers, you'll get 25 different opinions. Because without regard to "science", people have found their preferences and stick with them. I own 3 sets of fins. A full foot Scubapro Twinjet, an Apollo Bio-fin size S for wetsuit diving, and Oceanic Vortex size L for my drysuit.

Bottom line.....without hesitation I will choose the Bio-Fin over the others any day. I like the flexibility of the rubber, I can dive for 9 straight days 3 dives a day and not ever experience a cramp of any sort in my legs or ankles. After 2 days of diving with the Oceanic Vortex I have a slight cramp in my ankles, after about 4 days with the Scubapro twinjets I have the same.

My husband wears twin jets and thinks they are the best thing ever...has never had a problem with cramps. He thinks the Bio-fins are too flimsy. I think the more rigid fins work better for him. He has quite a bit more lower body strength than I do.

I purchased split fins right out of OW certification, and have always preferred them. I have tried paddle fins twice and both times was anxious to get rid of them. But I think that may have something to do with what I learned on and to what I became accustomed.

I think that different people will always have different preferences. I drive an SUV, my friend drives a diesel Jetta, my other friend drives a Hummer. We may pay some attention to science and advertising, but in the end, we tend to just get what we like the best.
 

Back
Top Bottom