One more split fin theory put to rest

[haha49]

Ok i have split fins and ill just put it this way.. it feels like i have nothing on my feet.. when i have them on i can atcually tow 2 people.. as i did while swiming as both my friends couldnt swim well so i had to pull them arcross the river.. i supect they were just lazy.. but i did it with tusa xpert zoom fins.. i find that my feet dont hurt after wearing them as there is less restance in the water.. yes i can go much faster with a solid fin but i have had alot of fins usaly cheap ones but i have a really old pair of scuba fins were the plastic was soft and very flexable and i found them to be a really nice pair of fins.. it all comes down to personal prefreance dont knock it till you trieded it..

 

[redacted]

I love my splits (in the right circumstances), but I've never read a bigger load of BS here. Simple physics of the frog kick shows that a paddle provides more surface area in a frog kick.

I think you may be oversimplifying the physics here. I know I have seen some paddle fins that are much smaller than some split fins. I suspect that a credible scientific treatment of this subject would involve more independent variable than "surface area" as well as appriopriate dependent variable. And there does seem to be a fair amount of disgreement on what those dependent variables should be. I don't think your "simple physics" which suggests it is just a matter of size provides an adequate answer.

I have a pair of Blades that I modified into split fins and a pair of Jet fins. I normally use a frog kick. I find no noticable differences in their performance. I prefer the splits mostly because the foot pocket is more comfortable. And, yes, I can back kick with both.

 

[Txfirefighter4305]

Being a matter of personal preference, I gave splits the benefit of the doubt and tried a pair my last dive, SP twin jets. Didn't like them, went back to my paddles. Just works better for me.

 

[RJP]

One more split fin theory put to rest...

Thank goodness - now we'll never need to see this debated here on SB ever again!

Did they happen to "put to rest" any theories about Air2, SpareAir, or BP/W vs BCD as well?

 

[Nemrod]

I think you may be oversimplifying the physics here. I know I have seen some paddle fins that are much smaller than some split fins. I suspect that a credible scientific treatment of this subject would involve more independent variable than "surface area" as well as appriopriate dependent variable. And there does seem to be a fair amount of disgreement on what those dependent variables should be. I don't think your "simple physics" which suggests it is just a matter of size provides an adequate answer.

I have a pair of Blades that I modified into split fins and a pair of Jet fins. I normally use a frog kick. I find no noticable differences in their performance. I prefer the splits mostly because the foot pocket is more comfortable. And, yes, I can back kick with both.

I did that same experiment a few years ago.I split some old UDTs by removing the center rin and then recontouring the blade. I also did the same with a rotten pair of old Jets. I did this to some old Vikings as well an a set of Plana Graphite full foots that had a torn pocket. You know--I hate to tell you guys---:

1) Force Fins Pros are quite possibly the fastest fin
2) standard UDT fins are as poweful as the Jet and possibly faster and do everything the Jet does better except go on to a drysuit boot.
3) Jet Fins are a good all around fin for diving due to their power, acceleration, reasonable foot pocket, price and availability but when it comes to speed they are not the top of the hill. I am talking about the XL size.
4)The fins I split did not perform that differently from the unsplit version. The UDT was softer without the center rib but frog kicked well.

This conclusions above are based on my simple experiments by swimming of laps in gear and timing myself at a moderate effort and by counting the number of strokes/cycles for the frog kick to get from one end of the pool to then other with no push off.

There is more to this fin stuff than blade area or shape or split etc. Some work really good and some don't and it is hard to put a finger on it. I have taped the vents closed on Rockets and Jets and I think--think--they work better without the vents for example.

I would really like a set of the Apollo XT to test against the Jet XL and UDT. Further, my tests mirror what the Navy found decades earlier before the Jet ever existed--the UDT is the King of the Hill. It toook fewer cycles to cover the same distance asd the Jet XL.

My arsenal:

N

 

[Eris Lucan7*]

I never was a frind of split fins.I use the 'Nermod speed' as latest...

E.L.7*

 

[CompuDude]

I'd loan you my BioFin XT's (size LL) to see the results of that test...

 

[SDAnderson]

Look at this.

 

[Nemrod]

I have seen that study before and noted that there was a significant lack of control and that he did not maintain--test to test and year to year--the same controls. He also did not account for his obviously improving physical conditioning and perhaps improved kicking form. His conclusions also lack one obvious factor--he simply lacks the power to kick the larger Jet XLs to their fullest capacity. Just as when I did my tests it is hard to hold things constant--I tried counting cycles in my frog kick runs for example but once you go into a standard flutter kick it is hard to count cycles. I have also observed that some fins do better once they are up to speed--such as Force Fins.

N

 

[Web Monkey]

I wear both SP Jets and SP Twin Jets (the black ones which are the stiffest) so I'll throw in my two cents. Yes, you can frog kick in them but you can't tow anyone. I did my rescue class in my Twin Jets and was miserable. I was kicking like crazy and I could feel the fins flexing in half while providing no thrust what so ever. Of course I'm 6'3" 195lbs and the guy I was towing was 6'4" 270ish, so maybe that had something to do with it as well.

You can tow anybody using Twin Jets. I do it on a regular basis.

They just feel softer than the Jets.

Terry