Why Jet Fins???

[Freeflyer]

OK, I'm new to the board, but I've been reading all about jet fins, but haven't really figured out why everyone likes them so much.

They seem to provide a lot of propulsion, but is that it?

Could someone enlighten me.

Also, why are split fins so well thought of. What's the idea behind split fins.

sorry if these are 'silly' questions, but I'm really interested to know. I'm looking for a new set of fins, and would like to make an informed decision. This board has been such a wealth of knowlege so far.

Cheers,

J.

 

[jonnythan]

Freeflyer once bubbled...
OK, I'm new to the board, but I've been reading all about jet fins, but haven't really figured out why everyone likes them so much.

They seem to provide a lot of propulsion, but is that it?

They're very stiff. They provide significant propulsion with little leg movement.. you don't need to kick and kick just to go anywhere. This also enables you to perform a variety of kicks (frog, backward, etc) efficiently. There was a thread recently with a split fin user frogging and doing a backward kick... displays the benefits of the Jets.

Also, why are split fins so well thought of. What's the idea behind split fins.

Not everyone thinks so highly of them. With a split fin, you generally kick quickly and have little resistance. You have to kick faster to get similar propulsion to a paddle fin. I think it's annoying as hell. They're also not nearly as effective as a stiff paddle fin in doing kicks other than a flutter. Whether they're "faster" or more efficient at a flutter kick than paddles is up for debate, but it's generally accepted (at least by me ) that the stiff paddle is more versatile.

sorry if these are 'silly' questions, but I'm really interested to know. I'm looking for a new set of fins, and would like to make an informed decision. This board has been such a wealth of knowlege so far.

Cheers,

J.

Not silly questions at all.. I once wondered the same thing
Not dumb questions at all

 

[Uncle Pug]

Stiff blade type fins like the Jets will give you traction in the water and that will allow you to transfer leg movement into immediate and substantial thrust. That will also allow you to put the brakes on as well as other maneuvers with precise control.

 

[Don Burke]

Freeflyer once bubbled... Also, why are split fins so well thought of. What's the idea behind split fins.

Divers using split fins generally have better gas consumption on slow to medium speed swimming involving flutter kick only.

 

[Uncle Pug]

Don Burke once bubbled...
Divers using split fins generally have better gas consumption on slow to medium speed swimming involving flutter kick only.

...the large stroke flutter kick is very inefficient in that it also creates drag.

A diver who learns to frog kick with Jets (or Turtles, ect.) will see a dramatic decrease in gas consumption as the kick~glide cycle of the frog is much more efficient.

One thing to keep in mind is that neither speed nor ground covered is necessarily the forte of any fin. That is what scooters are for.

If folks learn to move underwater with skill and efficiency using the frog kick they will maximize bottom time and distance traveled while minimizing gas consumption and they will not be destroying the viz for those who follow.

Today Shane and I did a couple of dives at an easy access site that is heavily used. Split fins were everywhere. The viz was great (40'~50') but when we got back up into Split Fin City the rototillers had reduced it to <5' in places.

We covered a lot of territory but at a pace and in a manner that not only allowed us to see things but to use the same tank for the second dive.

 

[pipedope]

I can stir up the bottom just fine with no fins at all.

Of course, the places I am working there is little or no vis and NO sport divers.

 

[Diver Lori]

Freeflyer once bubbled...
They seem to provide a lot of propulsion, but is that it?

Precision.

 

[NaCL H2O Boy]

jonnythan once bubbled...
Not everyone thinks so highly of them. With a split fin, you generally kick quickly and have little resistance. You have to kick faster to get similar propulsion to a paddle fin. I think it's annoying as hell.

Little resistance ensures less muscle fatigue, making you less likely to cramp and/or run out of air as quickly. Less air consumption results in getting to enjoy your dive longer. Conditioning your body to a higher cadence will always prove to be a more efficient approach in any type of physical activity. If you were planning on doing a 15 minute dive, then it wouldn't be as much of a factor. The bottom line is that most people would like to have as much bottom time as possible.

As for kicking faster to get similar propulsion, that's absurd. Two people of equal physical ability, one with paddle fins and one with split fins...the one with paddle fins will never be able to keep up. I've dove with people who use paddle fins and have legs stronger than myself, and when we kick it into high gear, I am always considerably ahead.

 

[jonnythan]

NaCL H2O Boy once bubbled...


Little resistance ensures less muscle fatigue, making you less likely to cramp and/or run out of air as quickly.

That is what Rodale's tells you, isn't it?

I've dove with people who use paddle fins and have legs stronger than myself, and when we kick it into high gear, I am always considerably ahead.

That's what I hear... and I also hear that splits are not good for use in currents. How is it they go faster in still water and slower in moving water? Besides, I've done my experimenting with splits, and I dive with people in splits. I know how it goes.

 

[d33ps1x]

These fins are all fine and dandy for the Cozumel Rodales fin tests with their 25 best buddies but they simply do not move a northern diver diving dry with steels.

That's just the simple facts of it.

As far as diving wet I still have a problem with a lack of resistance. What good is that if you have to therefore kick 10 times as much in little kicks to go the same distance?

Using splits is like using a bicycle in low gear and peddling like a maniac. Easy but whats the point. Especially considering that you give up on a lot of very versatile and efficient kicking styles.

As an owner of Mares Quattro's, IDI Turtles and two pairs of Atomic splits (for wet and dry) I think I can safely say overall the turtle and Quattro get way more bang for the buck. My SAC rate dropped a tonne when switching too them vs Atomics.