Pervasive Fallacy about Split Fins

[riverserf]

I finally finished reading ALL the posts and I gotta say there are a lot of people here who tried to twist this thread into something they wanted it to be rather than what it was started as: lots of people kept trying to highjack this and make it a split fin vs. paddles debate. It wasn't. It was about seperating facts from opinions and not pushing opinions off as fact.
I gotta say I've appreciated what Temple of Doom has attempted to do. For the people who weren't already prejudiced one way or the other I think they got that.

The thing that depresses me about Scuba Board is that so much of the time it's hard to find intelligent discussion on things. Most of the time, threads that start out with promise get sidetracked by people that just want to make wise-cracks and attack anyone with a different opinion than themselves. At one point or another they pull out the tiring...."I got more dives than you whipper-snapper...so you don't know nuthin'" Or...."You need more experience before you try talking about such things..." Seriously, I wish I could go through and cut the crap and just read the meaningful, intelligent, and respectful stuff. It would save sooooo much time.

In addition to Temple of Doom, I'll say thanks to the others who have actually made serious remarks because I'm still trying to decide whether to get a pair of split fins or not (Apollo Bios to be exact) and although this thread wasn't about which is better, some people did have some interesting things to say. And the worthwhile comments are appreciated by people like myself that may not have a ton of experience but we are trying to gain a little knowledge even when we can't be 'in the water'.

 

[in_cavediver]

I've posted this once or twice but here's the clarification.

- Splits have more thrust than paddles as per scubalab tests et al:

This is NOT proven anywhere in this thread. All cited studies use the flutter kick which is ideal for splits. They ignore ALL other kick styles in testing. This means that the most that can be gleaned is while flutter kicking, splits have more thrust than paddles. Sorry, you can't take it any further than that.

Lastly, who really cares anyway. The fact's of real world diving dictate far more than this simplistic 'tests' of thrust. There are reasons why groups of divers might choose specific gear over other gear. You don't see tec divers in splits. There might be a reason there.

Look no farther than observation and personal evaluation. Get what fits you and works for your diving. Then dive and be happy and use whatever floats your boat. Just don't silt the place up for the rest of us.... (which paddles and splits are both capable of)

 

[MauiScubaSteve]

When it comes to arguing for or against though, Temple has the rest of the thread outclassed.

I gotta say I've appreciated what Temple of Doom has attempted to do. For the people who weren't already prejudiced one way or the other I think they got that.

If SB is anything, it is a place where your facts have to be really good. Most divers who have experienced a wide variety of dive profiles know that underwater hardly anything is equal. For many the tests verify splitfins greater speed, in the tests, and just that. Until you dive it you can't really tell if you will like it. Some might be better served by spending the $200 on two days learning how to properly do the wide variety of paddle kick styles.

Look carefully at ToD's message below; as best I can figure it this is what this thread is all about, for him. It is certainly not the professor who assumes so much.

I wouldn't want anybody to change their minds about split fins (except maybe opening a closed one by debunking a myth). All I'd want is people to understand that:

If you believe the below assumption, which has been backed up with years of tests done (cited by Frank), then that means that the following conclusions are true.

Assumption: A diver swiming with the same effort can swim faster and thrust harder with splits than with paddles.

Conclusions, all else being equal and the only difference is fin:
1. Split fins are more efficient at swimming.
2. Split fins require less energy to swim at the same speed as paddle fins.
3. Split fins require less air to swim the same amount as paddle fins.
4. Split fins offer more thrust than paddle fins while swimming.
5. The above statements are all true in current and high drag situations.

The reason ToD may have used "assumption" (twice) could be because the tests really do not test the fins at normal diving speeds doing normal diving activities. They only tell us facts about the actual activities tested, and really only pertain to the group of testers. To make factual statements like those above you would have to have more detailed data from more testers at many more speeds, not just the speeds tested.

If you have any understanding of hydrodynamics, google a few word combinations (ie. underwater drag acceleration speed), even the experts can't explain it, much less predict it (assume?). My favorite result apears to be from somebodies navy, if you are really nerdy check out page 98.

All these variables make it highly unlikely we will ever have anything other than anecdotal evidence, just like with Nitrox. The fact is it's really hard to come up with facts that mean anything in diving!

Even thoses floating on the very top of this road apple (below) know where the answer is to be found

I think the NWGRATEFUll diver had it spot on many posts ago. Take it to the water and find out for yourself. Not all paddle fins are equal, some are inexpensive thermoplastics molded for $8.00 or $9.00 a pair or less and sold with huge marketing hype. Other paddle fins are high quality using good materials and design. The same with split fins. Some work very well, others not so well. It is not just paddle vs. split. It has a lot to do with the materials used, the design of the fin itself, the kick "style" of the diver, etc. This argument will go on and on. As Bob said "Take it to the water".

ToD knows who got schooled. Would really like to see video of his first dive with new dry suit and blue splits.