Do split fins have less umph than blades?

[Rob9000]

I have a pair of ScubaPro Twin Jets. I stopped using them and went to the Aqualung Caravelle since I felt like with the Twin Jets I just didn't have the current-fighting power I can get with blades. It is my understanding that with twin jet fins in general you do more of a faster flutter kick as opposed to the more powerful thrust kind of kick. When I did the more thrusty kick, it didn't seem to do much It is also my understanding that with split fins you are supposed to spend less energy cruising from point A to point B. But....I am a XXL kinda guy and I feel like split fins actually take more work to move my human parachute profile through the water. It is like a torque versus horsepower kind of thing.....splits have more horsepower and less torque, and I feel like I need more torque for the trailer I am hauling around.

Am I doing something wrong or is this correct?

 

[The Chairman]

I agree with your assessment.

 

[Rob9000]

Edit:
I found this thread that goes on about this subject:
http://www.scubaboard.com/showthread.php?t=191055

I guess in the end it doesn't matter what the theory or analogies are...it matters what we all like best when we are in the water. So theory aside, I wonder how many other people have the same impressions I do based on personal experience.

 

[divinginn]

i think you hit it on the head,torque for the paddles and high end horsepower for the splits,i will stick with my 28 year old jets,never saw the need for anything else,that is about the only original piece of gear that i first started with,replaced everything else.

 

[Charlie99]

I stopped using them and went to the Aqualung Caravelle since I felt like with the Twin Jets I just didn't have the current-fighting power I can get with blades.

With splits you can't start doing big wide powerful kicks to fight a current. That just does not work. You need to maintain the same small amplitude kick and increase the frequency. Split fins are more efficient and when used with proper technique absolutely are more efficient. What they don't do is deliver a strong thrust from just one kick. Splits require skill and discipline that many divers do not have.

I try splits every once in a while and am amazed at how efficient they are, but having started diving with monster flat blade original USD Blades fins, the splits just don't feel right. The funny part is the the Scubapro Jet Fins that so many others swear by also feel like little puny things compared to the USD Blades. I have to wave my whole legs around frog kicking to do what can be done with just ankle sculling with the Blades originals.

The saying "different strokes for different folks" is quite literally true.

 

[meesier42]

huh, I have to question what is "torque". I say, what most people perceive as "torque" is really drag on the fin that isn't moving you at all, just giving you a feel of resistance which makes you think that you are moving faster. This torque/resistance is the real reason why jets have the vents in them to reduce the resistance but they do nothing to help move you through the water.

 

[Charlie99]

When most divers post about blade fins having more torque, I'm pretty sure they are referring to the instantaneous thrust, particularly from a standstill. A single kick on a blade fin can get you moving, or can reposition you if current or surge has moved you. If you try to do the same with a split fin, it just opens up in the middle and doesn't give much thrust.

In my mind, a better analogy would be the difference beween a jet aircraft taxiing and a car. With the jet aircraft, the pilot has to crank up the engines a ways and there is quite a delay before getting going, but clearly the jet engine excels at speed.

When I first tried split fins, it reminded me of Wiley Coyote having gone off the cliff and pedalling furiously with his feet trying to claw his way back.

The splits also don't give you much tactile feedback because they are so each to kick back and forth in the water. A person used to blade fins will think he's not getting anywhere because you just don't feel much resistance when you are finning properly. But then you look back and see your buddy fighting to keep up, and you look at the bottom and see it zooming by.

I diver whose opinion I respect absolutely swore by the fins, and would use them to lead 2 dives per day, about 300 days per year. He had his choice of dozens of fin types, but chose a splitfin by Atomics as the very best for leading groups around reefs. The Atomics had just enough stiffness to them that he was able to easily control his orientation and position while stopped. With some other split fins, it is harder to control orientation because they don't "grip" the water as much.

 

[Nemrod]

Torque is a rotational measurement and has nothing to do with a fin kick. Fins don't have torque or horsepower. They do with proper muscle imput provide thrust which could be measured vs caloric burn or O2 consumption.

BTW, XL size Jet Fins are not all that "puny" in size, not as long as the USD Blades but time and time again the Super Jets have held their own and I must grudgingly admit that they are the premier all around scuba fin. Is it that I love them or hate them or love to hate them or hate to love them--oh--well--whatever, more serious divers have Jet Fins than any other fins.

I have used that stiffer Apollo Pro fin and felt it to be a fine fin, fast and powerful and frog kicks decently and feels good in a current with good control. N

 

[Ed Palma]

Uh, under which category do thermoplastic fins - with the neoprene rubber inserts down the middle fall under? I'm sure they're blades, but from this thread I get the impression that blades are the solid rubber jets or turtles. Would the finning technique of these composites be similar to using splits or a combination of both?

 

[DeepSeaExplorer]

With splits you can't start doing big wide powerful kicks to fight a current. That just does not work. You need to maintain the same small amplitude kick and increase the frequency. Split fins are more efficient and when used with proper technique absolutely are more efficient. What they don't do is deliver a strong thrust from just one kick. Splits require skill and discipline that many divers do not have.

I try splits every once in a while and am amazed at how efficient they are, but having started diving with monster flat blade original USD Blades fins, the splits just don't feel right. The funny part is the the Scubapro Jet Fins that so many others swear by also feel like little puny things compared to the USD Blades. I have to wave my whole legs around frog kicking to do what can be done with just ankle sculling with the Blades originals.

The saying "different strokes for different folks" is quite literally true.

You're contradicting yourself. If split fins "don't deliver a strong thrust from just one kick" then they don't deliver strong thrust from a bunch of kicks either. The fin that delivers the strongest thrust per kick is the winner.