Why don't split fins work so well in current?

[danvolker]

Mr. Volker:
We agree with your observation (in an earlier post) that many dive masters and experienced scuba divers are moving away from typical “scuba fins” and have adopted the use of freedive fins. We think this trend will continue as freediving grows in popularity and more scuba divers are exposed to the long freedive fins.

However, your comment about long (carbon fiber) freedive fins being appropriate for only very strong or elite athletes is not supported by our observations. Possibly your CF fins have very stiff blades?

It is important (for us anyway) that divers understand that freedive fins can be fine tuned to match the requirements of individual divers by varying the stiffness of the blades selected.

We offer a wide selection of freedive fins.. from the very inexpensive MAKO Competition Freedive Fins, to the standard fiberglass blade sand also the extra long 85 cm blades. Our fiberglass blades can be ordered in a variety of colors and different stiffness’s which should accommodate a wide variety of divers (including the elite athletes). As you have discovered, some of the newer, high tech blades coming to market have excellent “rebound” properties and function to store and release energy during the kick cycle.

We feel that in many open water situations, a pair of well fitting, full foot freedive fins will allow most divers to move through the water more efficiently. This is a function of a well fitting (full foot) pocket that supports the entire foot, has minimal flex at the sole and therefore transfers energy to the blade with little loss. Freedivers know that performance is tied to the efficiency with which they move and good fins will extend their dive time.

Scuba divers will realize the same benefits of a relaxed and efficient kick cycle and they may also discover that many fish feel less threatened and are more approachable, if the diver is not “kicking wildly” and pumping their feet furiously in an attempt to maneuver in a moderate current. Moving efficiently through the water also tends to reduce gas consumption.

Here’s a link to our fin page:
Fins


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OK, as if I was not long winded enough... I should have added that I use the stiffest carbon hybrid blades that are made by DiveR.....and in MANY of my past posts, one of my praises for freedive fin manufacturers, is that they typically offer several models from very soft ( for long duration spearfishing competitions--or for scuba divers that have never trained their muscles), to several intermediate stifnesses, and then the considerably stiffer for those that want to train to use this extra thrust potential.
I believe Mako to be a brand far superior to the Cressis that are the typical first freediving fins a scuba diver will experiment with...Cressis are sold at many dive shops, so are easy to come by, and fairly cheap....I would like to see more Mako's out on the dive boats , just as I would like to see more DiveRs and more of Bob's Excellerating Force Fins (which are what I use for wreck penetrations and are also very efficient for just cruising a reef.

 

[Scott L]

Agreed. A good boat...any boat I would consider using( any Captain I would use), will provide an upcurrent drop....the captain needs to know the descent speeds of his divers, and estimate the distance upcurrent to drop the divers....When we reach bottom, it is a leasurely drift into the wreck or reef...If it is a wreck, once you are approaching, it becomes your job to know how and where to approach to use the currents to your advantage. With the right captain, even a 280 foot deep wreck in a 5 mph current is relatively easy to get into.

Lazy ass captains that choose to anchor in strong currents need to be avoided like split fins

I can attest that Dan gets to the bottom first.

 

[diverdoug1]

its all about stroke rate and frequency, you can get a stiff blade and waste energy doing short strokes or splits doing long strokes- in current short strokes win due to drag profile/streamline.................................opposite to what has been augmented in this thread the physics rule supreme!

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close but no cigar dude!
It's horses for courses and nobody here has given the full goods(typical amricons)...yet! Intellectual property rights/benifit; i guess is holding this back(watch the nubs squirm), the failure of capitalism, with a repug that pays 14% on a "declared" 12million dollar year income(what a bunch of thieving mofo's they are at the top!).......
There is no multi-geared or length fin yet! The aqualung slingshot is the best attempt yet(like a chevy aquaglide 2spd autotranny!)- but it breaks!and isn't as good as splits or short rigid fins up current!
Hooooo wahhhhhhhh'
damo'

wtf???

 

[danvolker]

wtf???

I think he might have been smoking something

 

[diverdoug1]

I think he might have been smoking something

I think you might be right, He posted the following on another thread a few minutes later (I hope he recovered from whatever he was taking).

"ITS A GIVE IN TO MINING.....SADDNESS need a AL level national marine allowance the yanks and their alcoa and the chinese chinalco need to be publically made to be responsible for their actions....then there is CSG on the horizon(they will supply the borxite refineries smelts)...................the scum that rises to the top witout paying for it's full impact on an environment state!!!!! HATE!!! riddal me why you can't buy a residential block of land in Weipa?????? shame scumbags shame!
so sad of the political sell out on real/true democratic principles! wtf is George bush!!! thieves and murderers!"


Seems like Ozzydamo needs to lay off the fun pills or loco weed!

 

[SangP]

Hi Bob,

Speaking of ff, whatever happened to the excellerating fins (no longer available) and the v wings you were developing some time ago?

Many thanks again for your info on modifying my fins.

 

[Bob Evans]

sangP, Excellerating Force was pulled from the web, due to lack of production. But they are coming in slowly now. We sell over a 100 pair a day and production is making like 3 pairs per day. Sum it up..we will not continue at this rate for long. Their are several amazing fin designs laying in the mortuary. Like my Father Gordon B. Evans stated "Nothing good last for ever". Best, Bob

 

[SangP]

Hi Bob,

You are right, nothing good lasts for ever so get em while you can lol! Anyway, I got some ideas to share with you if you have the time.

 

[flots am]

sangP, Excellerating Force was pulled from the web, due to lack of production. But they are coming in slowly now. We sell over a 100 pair a day and production is making like 3 pairs per day.

Sounds like you need different production.

There are any number of plastic molding companies that would be happy for your business.

flots.

 

[danvolker]

You know, most scuba fins are really made of pathetically bad material for fins. I first realized that when I switched from the inexpensive cressi freedive blades, to carbon fiber and carbon hybrid fins ( as in C4's, in specialfins.com, and DiveR;s). The differences are so extreme, when you go back to the cr*ppy stuff most fins are made of, you actually think something must be broken.


Even take Scuba pro jet fins....while the material is not junk material--the fins do last forever, it is certainly not high tech, for what we need. It is stiff enough to offer a good control surface for precise technical movements when hovering, or reverse kicking, etc., and the material is not going to cause efficiency problems when the diver is frog kicking slowly...big push, long glide....it just needs to be stiff here, there is little need for re-bound or efficiency in the material.... But when a diver needs to go fast upcurrent for something urgent, the material is just, "dead". The fins keep pushing as the diver swims harder, but they almost seem to be braking as much as they are pushing.

The excellerating force fins ( yeah, those fins you can't get anymore, so why am I telling you about them ) are made of different material, and different desaign, and as the diver flutters faster and harder, the water flow over them begins to make the fin ever more efficient, and as the diver gets to very high power output, these fins are seemingly giving a huge power BOOST to the diver....Obviously this is not possible, but this is what it "feels" like to someone used to swimming hard with jet fins...someone like me that is a competitive cyclist, and can spagetti scuba pro jets as long as I want to....the stiffness is confused here....the jets are not really just a stiff fin, they are a fin that is so inefficient, that at high kick turnover, you are losing so much energy, they get tiring. If you train 40 miles per day on a bike, you don't get tired, you just get annoyed that the fins won't get your speed up equivalent to the "effort" you are putting in to them. The Excellerators Bob makes have me feeling like something in the fins has shifted gears as my kick turnover and power output ramps uo....and I start to move faster by far...it really gives the impression of power being added from somewhere else, because of the speed suddenly being generated. So you get divers rationalizing, saying " oh, you don't really want to swim fast", with all the variations of this. This is not a functional concept, because even though 95% of the time may call for very slow, deliberate, and no work at all....there are going to be times when the divers needs to be able to go fast, at least briefly. If you want to ignore this, you will either have to dive in still water tropical locations where there is never any current, or in caves with zero flow. Or, you will need to buy a $4000 scooter, and have it on every dive--then of course, the jets will always be the perfect fin for you......although I have used my gavin scooter with my Excellerators, and control is perfect, so you may hear me getting more and more negative about Jets. The problem here is, Bob cant make the excellerators in the quantities the diving population needs....meaning that for the masses, the Jets are left as the best controlling fin out there, and divers might as well get used to just not having to swim fast...they better not need to.

When I tried Bob's Hockey fins, and then the Excellerating force fins, this was a big surprise compared to the dead feel of conventional fins, much like when I first used the carbon fiber blades.... Bob will need to chime in, but I am pretty sure he is using a material very different than any other fin scuba divers can get....and this material makes a big difference in the re-bound, and the efficiency of the fin. and then of course, there is the actual design itself...most scuba fins are made to look pretty. Matching colors and bells and whistles, but function is always poor, and 99% of the scuba divers that are here on Scuba board, or in the entire world, will never demo more than a tiny handful of fins--and will never try the really DIFFERENT ones like the carbon fiber DiveR's, or the carbon fiber Mako's, or the radically different Force Fins Bob has created.
Divers tend to buy gear, and then convince themselves it is good, because they bought it. It would have to drive someone like Bob crazy, the way almost none of them have ever tried his fins and then had the huge experience difference "forced on them". ..... He must practice Tai chi, or have some very good relaxation fix for this....
What's your secret Bob, how do you stay so calm ?