Fins for diving currents?

[jim T.]

I used my Atomic split fins (original stiff blade model) in a 1.5 to 2knot offshore "surprise" current a few weeks ago and they did quite well. I was freaked a bit and near hyperventilating but any current that strong is going to be a lot of work.
I was doubly pleased when I had to tow another diver by the hand through the same/similar current a week later. (From previous experience I avoided the current but felt that I needed to assist my less experienced buddy who hadn't.)

Anyway, I'm not so convinced that all split fins are useless in current anymore as long as the blades approach the stiffness of a blade fin. I'm a huge jet fin fan but no matter how many bench squats, leg lifts, walks and extra potassium I take, etc. I still cramp with them. Some folks need the fin to extend along the length of bottom of the foot to the heel...

I find frog kicking to work well with the Atomic splits. I haven't gotten good enough at backing up yet to be sure.

I haven't dove with bio fins but have handled them on shore. They are similar in "floppiness" to Scuba Pro Jet Splits (the yellow ones) and I can't get anywhere in those although mileage definitely varies from person to person.

I haven't seen the newer/stiffer model bio-fins in person yet.

For me, the Atomics have been one of the best surface swimmers (on my back) that I've tried. (various S.P. models, Aqualung, Oceanic.)

Be sure that your split fin kicking technique is correct. It can make a big difference although I'm finding that most of the time a near bicycle kick is working well unless the current is strong then shallow fast kicks. I used to pool swim with my fins holding a large tupperware box lid in front of me to simulate current resistance and it helped to get the feel for what I'd contend with in current.

If traditional jets will work for you they're a great fin, but if you cramp up it'll be worse than any split fin when the s---t hits the fan. I'll use Jets for close quarters/wreck diving but for open water it's splits for me even with Drysuit diving and lots of weight,etc.

 

[bradshsi]

I used my Atomic split fins (original stiff blade model) in a 1.5 to 2knot offshore "surprise" current a few weeks ago and they did quite well. I was freaked a bit and near hyperventilating but any current that strong is going to be a lot of work.
I was doubly pleased when I had to tow another diver by the hand through the same/similar current a week later. (From previous experience I avoided the current but felt that I needed to assist my less experienced buddy who hadn't.)

Anyway, I'm not so convinced that all split fins are useless in current anymore as long as the blades approach the stiffness of a blade fin.

Current has no effect on fin performance. Thus if the fin is fast in still water it will be fast in a current. Since testing has shown that generally split fins are faster than paddle fins, consequently they are generally faster in a current.

I notice that a lot of people claim that split fins are not good in currents, without offering any explanantion as to why this would be so. I challenge anyone to offer a good engineering explanation (because there isn't one)

As best I can tell the difference is psychological (divers mind induced) not physical.

Be sure that your split fin kicking technique is correct. It can make a big difference although I'm finding that most of the time a near bicycle kick is working well unless the current is strong then shallow fast kicks.

Yep the kick is very important. Again according to the testing all fins (not just split fins), give more speed with short fast kicks. This ties in with my experience. You need to kick short and fast to make progress in the current. Big slow kicks will not work well with split fins.

 

[wunat]

Unfortunately fins are like every other piece of equipment... you don't know if it's crap until you've used it, hated it, and then found something better. Your best bet is to buy something sturdy that will last, while not breaking the bank.

Try borrowing someone elses before you buy... if you can!

This is very true. I owned 3 pairs of fins before I ended up with the Jets and is hooked with it. I tried and went back to the old fins and just so they don't sit around doing nothing and I always miss my Jets. Now I am diving the Jets more or less exclusively.

Preferences over dive equipments can be pretty subjective. But I have never have problem having to cut through the currents with my Jets. My buddies were amazed how I could go with them in currents with comfort..........................

 

[divingjd]

I've never had a problem with Scubapro Twin Jets in currents or in towing. You do want to use a short, quick flutter kick for maximum effect. If you want to try split fins with a stiffer composite, try the black Twin Jets. They are significantly stiffer than the other colors. If you don't want splits, the old Scubapro Jet Fins are obviously still a favorite of many divers. The Mares Quattros are probably about as good as it gets for traditional paddle fins. You can get a lot of power out of them, but they really take strong legs to get the most out of them.

 

[IslandCowgirl]

I am just a little bit taller and heavier than you. I too have the Atomics and the Scuba Pro Jet fins. My absolute favorite are my Scuba Pro Twin Jets. I rarely get leg cramps and I dive in current and surge alot. Good luck.


H - the IslandCowgirl

 

[Kaiviti]

I used my Atomic split fins (original stiff blade model) in a 1.5 to 2knot offshore "surprise" current a few weeks ago and they did quite well. I was freaked a bit and near hyperventilating but any current that strong is going to be a lot of work.
I was doubly pleased when I had to tow another diver by the hand through the same/similar current a week later. (From previous experience I avoided the current but felt that I needed to assist my less experienced buddy who hadn't.)

Anyway, I'm not so convinced that all split fins are useless in current anymore as long as the blades approach the stiffness of a blade fin. I'm a huge jet fin fan but no matter how many bench squats, leg lifts, walks and extra potassium I take, etc. I still cramp with them. Some folks need the fin to extend along the length of bottom of the foot to the heel...

I find frog kicking to work well with the Atomic splits. I haven't gotten good enough at backing up yet to be sure.

I haven't dove with bio fins but have handled them on shore. They are similar in "floppiness" to Scuba Pro Jet Splits (the yellow ones) and I can't get anywhere in those although mileage definitely varies from person to person.

I haven't seen the newer/stiffer model bio-fins in person yet.

For me, the Atomics have been one of the best surface swimmers (on my back) that I've tried. (various S.P. models, Aqualung, Oceanic.)

Be sure that your split fin kicking technique is correct. It can make a big difference although I'm finding that most of the time a near bicycle kick is working well unless the current is strong then shallow fast kicks. I used to pool swim with my fins holding a large tupperware box lid in front of me to simulate current resistance and it helped to get the feel for what I'd contend with in current.

If traditional jets will work for you they're a great fin, but if you cramp up it'll be worse than any split fin when the s---t hits the fan. I'll use Jets for close quarters/wreck diving but for open water it's splits for me even with Drysuit diving and lots of weight,etc.

I completely agree with you. I have Atomic splits and love them. They are stiffer when compared with regular splits and that does provide extra power. I feel that its all in the kick. I have a wierd type of kick with them. I use this kick a lot when i swim. Its a flutter kick but on every 5th kick per foot, i put in what i like to call an effort kick. That is a put a lot of power into it. So basically i will do 4 kicks, then the fifth is an effort kick. To make it a little clearer:

left foot kick
right foot kick
left foot kick
right foot kick
left foot effort kick
right foot kick
left foot kick
right foot kick
left foot kick
right foot effort kick

I try to make the flutter kick motions as fast as possible. Using this technique, i dont have a problem with Atomic splits in a current. This will not work as well with softer split fins.

 

[ChillyWaters]

notice that a lot of people claim that split fins are not good in currents, without offering any explanantion as to why this would be so. I challenge anyone to offer a good engineering explanation (because there isn't one)

Very true. You should also consider what type of fins will wear you out quicker. Doing big strong kicks with something like a jet fin will probably wear you out faster in a current than the little, near effortless, small kicks with the split fins.

- ChillyWaters

 

[L.A.Dave]

You say you didn't notice she was female?! What kind of normal guy would write that he was petite?!?!?!!?

 

[jim T.]

Well, even though i use the Atomic Splits most of the time, if it weren't for the cramping/lack of sole to heel support, I think I agree with those that feel the traditional paddle Jet Fins do have more power and a bit more allowance for kick and glide style finning even in a current but if I cramp up it's all over in a current.
Of course gliding is limited in current anyway.

 

[miketsp]

Current has no effect on fin performance. Thus if the fin is fast in still water it will be fast in a current. Since testing has shown that generally split fins are faster than paddle fins, consequently they are generally faster in a current.

I notice that a lot of people claim that split fins are not good in currents, without offering any explanantion as to why this would be so. I challenge anyone to offer a good engineering explanation (because there isn't one)

As best I can tell the difference is psychological (divers mind induced) not physical.
..snip..

Even though I've never used split fins I'll hazard a guess.
I've used various types of hinging fins and these are very efficient at low speeds - exactly because the hinge translates your up & down movement into rearward thrust.
The problem comes when you have to fight a current and you start to force the fins to the point where they hinge 90 degrees and then you're using a lot of muscle for almost no thrust, ie efficiency falls off drastically.
I suspect the same thing happens with splits. At lower power levels the fin should be very efficient because the controlled amount of water coming through the split cuts down the turbulence & hence the induced drag. However as you get into higher power levels, the lack of rigidity around the split will allow excessive curving of the fin and loss of thrust area.
So coming back to the original comment above, few divers really push themselves to the limit in still water whereas a current may force you to give all you've got. Then the loss of efficiency comes into play and the fact may well be that splits are not good in currents.

Personally I gave up on flexible fins and nowadays I swear by my Avanti Quattros. Some flexibility to maintain reasonable efficiency at low power levels, but when the chips are down and I fin hard, then I feel the thrust.