Split Fins and Tech Diving

[The Chairman]

Welcome to the Boards, DocRCH!

You will find the denizens of this board friendly and informative... But just like those fins, sometimes our opinions are split :tease:

(I agree with you on the split fins issue...)

 

[WetDane]

Well, I am sticking with the old guns on this one - I have watched so many splits silt out the environment in no time...

It is not really a competition in who can go faster - but a question of not stirring things up - I think the main thing is not really related to what the power of the fins are, but to the fact that when you dive old jet style fins, you to many technical divers also display an understanding of the issues of finning -

Obviously, if you have not taken doubles to a place where a silt out happens in one bad kick - you would have no clue what ID is trying to tell you.
And I have never had issues with my jet's being too heavy - actually, they allow me to dive without ankle weights and keep my good trim... I can't speak for others trim or non-qualified use of equipment.

Anyway -
Big T

 

[DocRCH]

Again, Iususlly dive with dbl 98's and two 40 stage bottles and with a canister light. I am trimix trained. I dive deep wrecks off of the NE coast. When I hear someone state that the split fins are "not stiff enough" I conclude that they do not understand the difference between efficiency and just being stiff. If stiffness were the deciding critera, the SS fins would be great. There are issues with frog kick technique that may be a factor in cave diving. Most of the people that I know who say that they do not like the spilt fins because of lack of stiffness have not tried using them. If you are interested, give them a try (more that one dive ) .

Doc

 

[scuba_adventurer]

I, personally, would not use the Twin Jet for anything other than recreational diving. I use them, and I really like them, but they are not for Tek.

I have seen them silt up lakes many times if they are not used properly, and I know this would be an even bigger problem in a cave. The Atomics are stiffer, but stiffer yet, the Twin Speeds, might do the trick.

I have seen an openwater diver have to unplug his low pressure inflator at 60'(big leak), and since he was a little overweighted, panic. He could not swim himself up because of his split fins. I know he made probably 3 mistakes, he should not orally inflatedd, he should not have been overweight, and he should not have panicked. If you were to have a buoyancy failure in a wetsuit deep with doubles, it would be a lot of work to swim all of that gear up with Twin Jets, maybe even impossible.

I also think that, from my personal experience, I would rather wear paddles with doubles just because of the extra power. I also am faster in paddles than Twin Jets (DM swim tests).

 

[large_diver]

Diving deep with steel doubles and a wetsuit is probably a no-no in the first place, split fins or no. Too much un-ditchable negative buoyancy in the event of an event like the one you described above.

 

[Tekdiver]

I've tried most of the split-fins on the market and the Volo/Tiger style as well. When cruising with a single in your local lake or quarry or drifting in Cozumel or Caymen they work very well. Particularly if you have knee or hip problems. But most of my diving is in doubles or large singles most often with stage(s) and they don’t provide enough sustained thrust in currents.

I’ve jumped off a boat with a 120cu.ft. and 50cu.ft. stage off-shore North Carolina with ripping surface currents and was flat worn out with the “fast kicking” it took just to get to the hang line. I’ve also tried to enter Little River (a high flow cave) in FL with Volos and dual 95’s and they just folded up. I had to abort and change fins.

The vortex created by all of the split fins is difficult to control in high silt environments like wrecks and FL caves. I’ve used the TUSA splits with a modified frog kick in the caves of Mexico with pretty good results but that’s a heavy silt/sand, low flow environment.

The best fin that I’ve found for all of MY types of diving is the Mares Plana Avanti. Just the two tunnel version. Stiff enough to control in high silt environments and long enough to give sustained thrust.

Just FYI: I’m 5’7” and 150lbs. So on many of my dives, the gear weighs as much or more than I do.

 

[Tekdiver]

Hey ID,

Re: "As long as there are "technical divers" there will be regular fins.

Trust me on this."

What's wrong with "regular fins"? I would really like an answer on this. And what's the gripe with tech divers (if they're real)? They bring you most of your advancments in gear through the mfgs. including split fins. All the gear are tools but you have to know enough to pick the right tool for the job. Yes, you can drive a nail with a Crescent wrench but a hammer works so much better.

 

[monster]

Have to agree that the problem with splits is really just the lack of flexibility in terms of kicking style. I've tried the Apollo BioFins (1st generation) and the SP TwinJets, and found that neither held a candle to JetFins on frog kicks. I find that splits don't glide very well, either, which is how I normally swim when I dive.

Haven't tried any of the new generation, though, such as the Atomics, or the TUSAs, which are supposedly all better performers because of the inserts or thingamajigs that help stiffen the "propeller" blades.

As for the vortex... yes, I've seen those puffs kicked up by propeller fins, but I see them with normal paddle fins, too, so I guess it's got to do with kicking style.

 

[donooo]

While researching equiptment, I checked out what a lot of tech / cave divers in Mexico were using. FORCE tan delta, came up more then once. Stiffer then the other FORCE models , but not split, not regular.

adios don O

 

[monster]

Are these Force Tan Deltas variants of the Bob Evans Force Fins? Yeah, they aren't split, but while they aren't "regular" either, they're pretty much modified paddles. I expect they don't cause the same vortex thing that the splits tend to.