Split fins.... YES or NO

[whozamajigit]

I dove for about 6 years with US Divers Blades, and I thought they were just fine, and I still do, however recently I switched over to black Scubapro TwinJets, and I'd highly recommend them. They work just the way the advertisements say they will; minimal effort, maximum output, little resistance...etc etc. They're great for DM'ing a group because they make it very easy to kick up to top speed to wrangle up stray divers. I also love them because the foot pocket is oversized, so that an X-Large size fits me like a XX-Large size of any other type of fin would, and it's often hard to find XX-Large and larger sizes. They also sport the advantage of having the black TwinJet, which is negatively buoyant, and the coloured TwinJets, which are positively buoyant. I dive with the black ones, and because I use a drysuit, this eliminates the need for any ankle weights for myself. These fins also far surpass paddle fins in terms of surface swimming power. My only complaint is that extra effort is required when in an upright position, and trying to maintain your depth by finning, ie; if you're taking a photo. And as far as kicking up silt with a flutter kick goes, well, I dive in Victoria. Here, we know about silt and poor visibility conditions. As long as you're not swimming with your bellybutton in the sand, you won't be kicking up enough of the bottom to worry about.

 

[Stirling]

After reading some of the comments in this thread, a person might go away believing that the laws of physics somehow don't apply to split fins. The first pair of serious fins I ever owned was a pair of JetFins that I got in about 1972 (and still own). The first pair of split fins I ever owned are the Atomic fins I just purchased last year.

Any fin will dig a trench in the bottom if that's what you use it for. But the idea that split fins throw water "down" more than paddle fins and therefore stir up the bottom more than other fins do is just wrong. In fact, the reason that split fins are generally faster than paddle fins for the same output of energy is that they *don't* throw water up or down, nor do they spin it off to the side in a silt-stirring vortex. Instead, they do a better job of pushing water straight back - and Newton's Third Law says that makes them faster. Split fins are simply more efficient, and will produce more speed with the same effort than you will get with a pair of JetFins.

It is *divers* who swim with their feet pointed down (with any kind of fin) who drive water down into the bottom and stir it up. No doubt it is true that, because split fins are more efficient than paddle fins, if pointed at the bottom they will do a better job of digging a trench than you could get with a JetFin using the same amount of effort.

I keep reading that you can't frog kick with split fins, but I keep doing it, anyway. Scuba Diving magazine compares fins by testing them, using flutter kicks and frog kicks, and somehow their test divers can frog kick in split fins, too - because they do it and report that some of the fastest speeds they get in the frog kick test are with split fins. The long blades do make it feel awkward, at first, but that's what practice is for.

The real advantage that Jet Fins have over split fins is that the blades are smaller and - more importantly - stiffer, and therefore easier to control. Of course it is easier to make smaller movements with the stiff blades of JetFins to avoid stirring up silt than it would be with the long flexible blades of split fins. So you trade some efficiency for better control over the action of the blades. Fine. I have no interest in cave diving, but I also have no problem believing that JetFins are preferable to split fins in enclosed spaces where silting is a problem, because the smaller stiffer blades give you more precise control over the movement of the water around you.

But the idea that split fins are only useful for identifying people who don't know how to swim properly is just preposterous. I'm pretty new to this board, but I am really puzzled by the dogmatism that keeps flashing up in some of these discussions.

 

[RiverRat]

Here's my take:

I started diving in Jet Fins 2 years ago and I've grown to love them. I'm still a fairly new diver but I have dove in local lakes and quarries, shore dives in RI, wrecks in NC, walls and reefs in G. Cayman, Bimini etc. So far I've not had any major leg cramps or been unable to keep up with any divers. Not that I'm in a race or anything. I suppose for some folks splits may be better. Seems like they're more efficient if you use a modified flutter kick. I compared my Jets against some stiff splits in a pool and found that my Jets are very strong "off the line" so to speak. The splits felt "flimsy" but if you start to haul *** and modify your flutter kick they did seem to start to "become" more efficient, requiring less effort to swim. But my question is, who swims around a reef at FULL BORE continuously during the course of a dive? I'm also into photography so I like the superior handling of the Jets. I also got blown off the line diving the Bimini Barge in strong current (messing with my camera) and my jets put me right back on with minimal effort. I think splits have a place maybe, but they're overrated to say the least.

 

[MASS-Diver]

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I keep reading that you can't frog kick with split fins, but I keep doing it, anyway.

You aren't doing the kick correctly - it's pretty impossible to have a half decent frogkick with splits - sorry that's just the way it is. The fin is way to flimlsey to work right for this kick, it's not even close.

Let me guess - you claim you can swim backwards in splits too? Splitfins are a nightmare because you can only do a one kick with them and it's a kick that should pretty never be used - atleast it's inefficent, at worst it stirs up the bottom for everyone else.

Hint - when you see something in SCUBA Diver mag, you may want to question it, espically anything about how great $180 splits are.

 

[triggertravel]

I just sold my frogs on ebay as my cramps have gone away since going to split fins. I can swim much faster w/ them too w/ less energy. This my be in me head but it seems the traditional fins take more energy but may have benefits in strong currents and in situations where kicking up silt is a concern.

 

[Charlie99]

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I keep reading that you can't frog kick with split fins, but I keep doing it, anyway.

You aren't doing the kick correctly - it's pretty impossible to have a half decent frogkick with splits - sorry that's just the way it is. The fin is way to flimlsey to work right for this kick, it's not even close.

Let me guess - you claim you can swim backwards in splits too? Splitfins are a nightmare because you can only do a one kick with them and it's a kick that should pretty never be used - atleast it's inefficent, at worst it stirs up the bottom for everyone else.

Pretty amazing claims MASS-Diver, considering that you probably have never seen Stirling.

While I have not seen Stirling, I have seen other divers doing frog kicks quite nicely in Atomics Biofins. They are stiffer than most (all?) other splits.

Your claims about plit fins being inefficient are way off, and the "stirring up the bottom" comments are out of context.

If you are negatively buoyant with fins pointing towards the bottom, then yes, split fins do a good job of rototilling the bottom. Even better than Jets, because splits can throw off a vortex that can go quite a ways. But that's a problem of technique, not an inherent problem in the fins.

 

[Charlie99]

As I said in my first post in this thread, one must try out the fins to really understand the difference.

For me, this is how the fins work -----

US Divers Blades originals. Big flat non-vented fins. Absolutely the best fin and anybody that doesn't agree is a ^&$#@*&&. Lots of instantaneous thrust from either big amplitude flutter kick or traditional frog kick. The long length, plus the stiffness make the fin suitable for a highly modified frog kick where my feet stay close together and most of the power is from my ankles driving the fin tips. Very, very efficient at slow speeds. Beats classic frog kick. When more speed is needed, a classic frog kick with lots of leg movement works nicely. When max speed is needed, a large amplitude flutter kick is really high speed, although also very high energy. Very easy to helicopter. Kind of awkward to back up, but can be done.


Atomics Biofins. Rather stiff split fins. Very little resistance to kicking. Almost felt like I didn't have fins on my feet. Assumed I was going very slow until I actually looked at the bottom and realized I was zooming along at a relatively high speed. The feel "funny", because a big amplitude kick just doesn't grab hold of the water and give a big instantaneous thrust the way stiffer fins do. OTOH, absolutely superior for finning in current, PROVIDED YOU KEEP DOING SMALL AMPLITUDE FLUTTER KICKS AT HIGHER SPEED. If you try to increase you speed by kicking "harder", i.e. bigger swings, you don't get much if any improvement. I only did about 10 dives with these about 3 years ago, and never really got the hang of going backwards with them, but I've seen several other divers do backward frogs with these. Frog kick with these felt more like a Jetfin than the Blades (less resistance, neede to make big leg movements). I ended up not buying them. They were incredibly efficient and very easy on the legs/knees, but I just didn't like the "mushy" feel of not getting instantaneous thrust with a single big kick. OTOH, a dive boat owner that I highly respect loved his Atomics and used them for 500 dives a year for several years, although he had ready access to several other fins.


Jetfin clones by IST. I found these on the bottom of a local dive site last year, so I can use them anytime I want, but have only done about 15 dives with them. Smaller area, and much shorter length than my Blades (although bigger than SP Jets). Can't do a sculling kick / frog kick with just ankles because they are too small and too short. Works well for a classic frog kick where I make large motions with my legs. I find it much, much easier to kick backwards in the Jetfin clones than any other fin I've tried, but rarely do I need to back up a couple of feet in my type of diving. .

SP Twin Jets. Similar to Atomics Biofins, but more flexible. Just this morning I was watching a guy helicopter and move in reverse with these fins. Looked effortless, but I have no idea how long he worked to develop those skills. I only did 2 dives with these because it was clear that, for me at least, the Biofins is the better split fin.

Clearly, YMMV,

Charlie

 

[StSomewhere]

I noticed when watching IMAX "Coral Reef Adventure" that most of the divers where using splits. What is up with that? I mean these guys are not REAL divers...right?

I imagine hauling around that beast of an IMAX camera with underwater housing is a real bear. If they are using splits moving that thing around well enough to get that kind of camera work then they must know something.

 

[RiverRat]

I imagine hauling around that beast of an IMAX camera with underwater housing is a real bear. If they are using splits moving that thing around well enough to get that kind of camera work then they must know something.

Or maybe they don't, maybe busting their tails needlessly

 

[solo_diver]

I use TUSA X-PERT ZOOM fins and have been thinking about getting Non-Split fins...

What do you like?

yes and no

i use split fins and love them

but i've recently been educated on some better finning techniques and the same source of info suggested using non-split fins for it so i will try non-split.

I use apollo bio fins and love em. a bit expensive. best way to find out is next time you're on a dive boat (i did this btw) ask another diver if you can borrow his/her fins (if they would fit) and try them for a dive.

works.