Split fin haters... please explain:

[danvolker]

When I think of why a Military use could be possible, I think of the huge differences between what they do and what we do...for instance :

1. I don't jump out of helicopters with my freedive fins on--if I did, I would break them.....
2. If a bunch of SEALS were to be dropped 5 miles off shore, to swim in covertly, and then run several miles ( stealth approach to behind enemy lines objective) where peole could be trying to kill them....they would want fins that would NOT utilize much leg muscle, but instead run primarily on the cardio system...breathing rate could be high, this will not matter....speed will not be a big deal in water, only being able to swim in ....when they hit the beach, their legs need to be fresh, and their lives may depend on this..When our diving is done, we can relax and typically will NOT be doing a run for our life...
3. SEALS heading for a beach will not care about silting...in fact, they may like the idea of hurting visibility all around them, like an octopus inking, or goliath groupers with their silting behavior to allow them to functionally disappear to potential predators....So the silting potential of the splits is high, and just fine with military applications...for us, silting is really bad, and split fin divers tend to be the worst offenders....

 

[mdb]

dj_The fins could be going for rec, use, although I doubt it. We just know that the military orders are in large quantity and are always in size Large or XL.
The orders come from both the East and West coast.

 

[MRadke]

So with all of the arguments back and forth, I guess I should put a Twin Jet on my left foot and a Jet on the right and see whether I am involuntarily turning clockwise or counterclockwise.

Dan Volker - As a cyclist, I would have thought you would like the higher cadence of a split fin. Are you a spinner (90 - 100 rpm) or a masher? What gear inch are you turning over at what speed and/or cadence?

 

[danvolker]

So with all of the arguments back and forth, I guess I should put a Twin Jet on my left foot and a Jet on the right and see whether I am involuntarily turning clockwise or counterclockwise.

Dan Volker - As a cyclist, I would have thought you would like the higher cadence of a split fin. Are you a spinner (90 - 100 rpm) or a masher? What gear inch are you turning over at what speed and/or cadence?

Very insightful comment...
I used to be a track sprinter, where I would sprint to 140 cadence....however, I also time trial, where I prefer to run at 80 to 90 rpm. I have a lot of torque, so can push at even 70 with good efficiency, if I need to allow cardio to rest for a while....

With my Dive R freedive fins, shape of kick creates at least 5 or 6 different "gears".... I have a very definite slow and big amplitude kick, that uses almost no heart rate, and propels me at a easy crusing speed which is faster than a high speed with splits( meaning a speed the split user can't reach or sustain)....this being a max bottom time type of kick, or max sight seeing of small life....with hovering motionless frequently....
Progressive shortening of the amplitude, and a change in the angle of the fin, to the extreme for high speed to follow dolphins....has a very high kick turnover with the DiveR freedive fins, with the upstroke almost equally as thrust creating as the downstroke--you create an "oscillation" of the blade, of sorts, that produces incredible speed. This speed can be sustained at a near anaerobic threshold type effort.....I could probably do this for 45 minutes to an hour in an emergency scenario, at a heart rate of around 170 to 180bpm...Last time I did this, it was following a pod of bottlenose dolphins for about 15 minutes or so....I was kicking in the maximum fashion, to increase the pace of the gavin scooter from maybe 3 mph to closer to 5.5 mph. ..the speed dolphins relax at when cruising a reef....see Dolphins on Pauls Reef WMV 7 Mbps 1080p - YouTube
Without the scooter obviously I cant do 5 mph, but I can run at a speed far in excess of what any split fin diver could ever imagine--even if we are talking an Olympic athlete that should be able to "smoke" me on a bike or in the water.
Alternatively, I can reverse kick with precision, or frog kick with amazing glides between big frog kicks .... However, in my deep shipwreck penetrations, I would prefer something like the Bob Evans Hockey fin--it allows perfect frog kicks, it is as easy to reverse kick with as it is to go forward with, it does GO fast when you need to, and is not a fin I would imagine most divers would silt with even when not trained.

 

[Allison Finch]

I spent my first 30 years diving in SP jet fins doing all kinds of diving, including penetration cave diving. On a whim, I tried my sister's bio fins. While I personally found the bios too "mushy" for my likes, I liked the feel of the splits. I went through several other splits and settled on the SP twin speeds. They were the stiffest I found at the time. Due to my years in caves, I rarely flutter. I mostly frog kick. I find them excellent!

I dive mostly Pacific waters with high current potential. I can always keep up, or pass, paddle finners in high current. If I have found one thing I feel they are not as good as paddles on, it is back kicking. While I can do it, it is not AS easy as in paddles.

All in all, the advantages FAR outweigh the one disadvantage. My jet fins seem to stay in the closet. I do photography now and find that their ability to do fine movements (Not so much in the mushy bio fins) are just fine in the splits I use.

 

[MRadke]

Thank you for a very complete answer. It sounds as if you turn the big gear very well, whether on land or in the water. If you were coaching a relatively new cyclist, would you advise them to 'just ride the big gear' or would you tell them to ride in the tallest gear that they can maintain an 80 RPM minimum cadence in?

 

[danvolker]

Thank you for a very complete answer. It sounds as if you turn the big gear very well, whether on land or in the water. If you were coaching a relatively new cyclist, would you advise them to 'just ride the big gear' or would you tell them to ride in the tallest gear that they can maintain an 80 RPM minimum cadence in?

Im about to leave for diving, so I can only answer briefly......Use intervals to push the big gears and spin them up to 90 or 100...2 minutes is max for this, 1 minutes good to, with 4 times thee rest.
If a new cyclist trys to push a big gear too soon, and too long, they hurt their knees.....I built up to this over a very long time

 

[djcheburashka]

dj_The fins could be going for rec, use, although I doubt it. We just know that the military orders are in large quantity and are always in size Large or XL.
The orders come from both the East and West coast.

If they were actually being issued to soldiers for military use, you'd know because the military would impose all sorts of manufacturing requirements, contract requirements, etc.


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[MRadke]

Im about to leave for diving, so I can only answer briefly......Use intervals to push the big gears and spin them up to 90 or 100...2 minutes is max for this, 1 minutes good to, with 4 times thee rest.
If a new cyclist trys to push a big gear too soon, and too long, they hurt their knees.....I built up to this over a very long time

That is my point. I believe that a good many divers dive for fun and recreation and may not have the strength, endurance or desire to push the 'big gear' efficiently.

I've used splits to this point but now own a pair of jets, so I have a decision to make before I take AOW in February.

 

[mdb]

If they were actually being issued to soldiers for military use, you'd know because the military would impose all sorts of manufacturing requirements, contract requirements, etc.


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They do.