C4 Flap 25´s or C4 Flap 80´s for freediving

[Shark 1980]

Hi guys,
I tried a lot of plastic bi-fins, Specialfins carbon bi-fins and the last year I use C4 Flap 25´s which I consider to be the best fins I have ever had. I am quite strong an muscular (187 cm / 86 kg) from fitness training, but my freedive style is all about "slow and easy" with minimal cumsuption of air... that is the reason why I prefere soft 25´s and don´t want harder. But in future I consider to buy longer C4 Flap 80´s for pure freediving (CWT) and for deep wreck diving. (Deep means up to -40m for me ).

Is there somebody who is experienced enough and can compare these two C4 fins?
a) what is the difference in movement / comsuption of oxygen?
b) is it worth to have 2 carbone fins ? or is the difference betwen these fins unvalued and should better spend money on Glide WW (now I use Nemo Wings but don´t consider to be good :naughty)

Please don´t suggest new Mustangs or 81´s ...cos I don´t want to use this stupid footpocket. Also would appreciate an advice from somebody who really could compare these fins and have some experience in freediving, so beginners take a break please )

Thank you for your views

 

[trux]

Not that I can help comparing the 25's with 80's (I used Flaps 30), but am quite interested what is wrong with the Mustang footpockets? Did you try them out and did not like them? Heard negative feedback? Or is it just the look you do not like? Or perhaps the color is not the right one?

 

[Shark 1980]

Hi Trux )
I have never tried this footpockets but talked with a few freedivers who have that opportunity and they wasn´t much enthusiastic.... One of them said the footpocket is too wide at the point of the end of footpocket and the begining of the blade (you sure know what I mean).

And my opinion... when I consider law of hydrodynamics which say that fins should be slim at the point of footpockets as much as possible, because when the diver kicks his legs during the diving, he push the watter in frand of and behind his leg. It is a loss of oxygen, loss of energy and it doesn´t help to move forward. This is the reason why are some fins, for example normal scuba/schorchling fins, slim at the point of fingers of the foot and then are extend to big width. Some of them have even holes next to footpockets to watter could run through and to avoid ineffective pushing the watter. Why I am talking about that? Because I don´t understand why these "C4" footpockets are so extended at the point of footpockets... The resault is ineffective pushing of watter at the point of footpocket (especially at the point of foot-fingers). I suppose this widding was made to could push holes for srews further from each other and to avoid breaking of blades at this delicate point (I know a lot of your blades broke at this point). Thanks to that it is more firm and don´t break anymore. Also could be separationed right and left foot, what can be comfortable. But I think that it lost the efficiency of forward movement of the diver a little.... and I am not talking about the triping the fins each other at this point and about the fact that I am sure that my wider food would not fit these "italian style - boots" ))

But that is only my opinion...

 

[Jon]

I've owned 25's, 30's, 40's, 80's and now use Mustang 30 flaps.

The Mustang footpocket is the most comfortable footpocket I have ever used- hands down.

The 80's I owned were my favorite, but I sold them to buy a monofin. If I ever get the cash together I would love a pair of Mustang 81's.

I found the 80's to be softer than my 30's, and closer to my VTR 25's. I never found the extra length to be an issue. It does require a bit slower, and wider, fin kick.

I have a normal, to narrow, foot and find Sporasub pockets to OMER's- because they fit my feet better. Maybe that bit of information will help you form a different opinion of the Mustangs. I would LOVE to try out that new C4monofin with the Mustang footpockets on it- it looks to be as comfy as can be.

Jon

 

[hudasmt]

You might wanna check Spierre Fins coz he customize the blades from your body structure and length of the blade will go up to 82 cm. You can choose the stiffness of the blades also. He is also open to personalizing your fins, i had my call sign printed at the back of the blades. It is being used by the South African Spearo Team like Jaco Blignaut. He is doing this for both carbon and fiberglass. But I'm a newbie so you might wanna disregard my post thou,like you said. Sorry, was just trying to be informative. I also wanna buy the C4 80 or 81 fins but like you, i have issues with the footpockets. Good luck on your search.

 

[Shark 1980]

Hi Hudasmt
I heard about these fins... but this is not a big deal, because a lot of producers can customize stiffness + lenght + width to your personal need. I already had customized Special Fins and Leader Fins do that too....nothing new.
I am quite experienced in that and no doubt - C4 bi-fins are the best for my kind of diving...

So the qustion is only about C4 80´s...

 

[trux]

Hi Trux )
I have never tried this footpockets but talked with a few freedivers who have that opportunity and they wasn´t much enthusiastic.... One of them said the footpocket is too wide at the point of the end of footpocket and the begining of the blade (you sure know what I mean)...

The idea behind the wide footpockets with rectangular connection to the blade is the laminarity of the water flow over the blades. Using narrow, long, and constant width blades is the principal advantage of C4 against other brands.

You are right that any area of the blade that is not in the ideal angle of attack during the kick causes great transverse drag. That's why some (mostly scuba) fin manufacturers use designs with opening, or channels, to reduce it. On the other hand, any irregularity of the shape disturbs the laminar flow, and adds a lot of turbulences. And laminar flow is especially important at long fins. For these reasons, it is difficult to tell whether the wide footpockets really add more drag, or whether they oppositely rather greatly improve the laminar flow, and hence reduce turbulences, and the wave drag.

As for touching the footpockets when kicking - since the blade is equally wide (and rather narrow in comparison to other brands) all along, if you keep the blades parallely (as you should for optimal efficiency), you do not risk touching them. I'd tell that it is rather the more usual blade which is wide at the trailing edge that is not optimal from this point of view - you either touch the tips when kicking, or have to keep a significant angle between the fins, hence losing efficiency.

I am not claiming the Mustang footpockets are more hydrodynamic than the classical model - for finding that some extensive tests in a hydrodynamic tunnel would be needed. I am just telling that there is a reason for that design, and one should not reject the concept without verifying or testing.

 

[Shark 1980]

I know what do you mean Trux. Of course there is a reason for that design = prefent from breaking blades + reduce of turbulence in case of blades which are narrow from the begining. But somebody should put these footpockets on, without blades and try to kick with them in swimming pool... Don´t know if he would go forward or backward )

I know.. maybe I should try first, but I am sure this footpockets are too narrow for my wide foot and also don´t wanto to spend money on something what maybe wouldn´t work properly for me... even if my sporassub footpockets works good with traditional shaped C4 blades.

By the way... I have never seen any recordmans or really good freedivers to use that. Everybody of them prefere the old shaped C4 blades with classical footpockets. Even my boss who I working for as freediving instr. in my spare time is a little sceptics about this new inventions.... maybe he is oldfashioned but he is one of the most experienced freedivers in my country... he reprezented our country together with Martin Stepanek in Pacific Cup 2002 and many others...

As regards these footpockets I am sure that a lot of freedivers will be happy with them... but a lot of freedivers will have too wide foot (as me) and I am not sure if anybody will have any success with these footpocket in serious competiting freediving.

 

[Shark 1980]

This is what I am talking about... http://www.spearboard.com/attachment.php?attachmentid=62815&stc=1&d=1192022220

 

[Jon]

That's an aweful lot of assumptions about a fin that you've never even tried on. So much for "freeing your mind".

I find that surface swimming, while spearfishing, is much eaiser with the Mustang footpockets than with my old OMER/Picasso/Sporasub/Esclapez/Spetton footpockets. The blade angle is better and the thrust is more forward. There's also a whole lot less surface splashing.

I didn't know that ANY records were still be set with any bi-fin? Everything I see these days, in the record department, is done with a Russian stlye monofin.

Jon

 

[trux]

I didn't know that ANY records were still be set with any bi-fin? Everything I see these days, in the record department, is done with a Russian stlye monofin.

No, that's wrong. Untill recently the DYN records were often held by bi-finners - especially Tom Sietas with C4 80's and Stephan Mifsud with custom Brier's belong to the long ones. In contrary CWT is indeed dominated by monofins since a while.

 

[Shark 1980]

Jon I don´t want to argue with you my friend
If you would read carefully my reply, you would see:

1) I agree there would be a lot of freedivers who could be happy with these footpocket. I am sure these footpockets could be much more comfortable for a lot of freedivers (and for you) than traditional footpockets.

2) But the only footpockets which I can use is sporasub / nemo / beuchat. The others (cressi, omer, ect) are to narrow for me. Be sure I would like to try this new footpockets, but the only chance how to try it is buy it... and I am not so rich to could spend money on things which may not would work properly for me.

3) As you said... this fins can be great on surface and for sparfishing, but I am interested mostly about CWT, DYN and pure freediving... so I don´t care about how much comfortable but how efficient it is.

4) Of course I know that world records are set with mono, but we talk about bi-fins now and I didn´t talk about world records, but talked about serious competitive freediving ...a lot of good competitive freedivers in my country still use C4 bi-fins for their recreational freediving and for national competitions... but none of them use C4 footpocket.

As I said before.. be sure I would like to try it, but don´t have as narrow foot as you and don´t have any opportunity, because all people around me use traditional shaped blades + sporasub footpockets.

so don´t be upset with me

 

[Shark 1980]

To could see what I have on my mind with these C4 footpockes, look at this picture... the red coulour is the watter flow during the kick forward...

Of course that there is an advantage of less watter turbulence because of narrow blade from the begining... but I am not sure if this advantage is big enough... just look at the picture..

 

[trux]

Well, the picture does not prove anything. I can take the same photo and draw turbulences and flows in the exact opposite way. The mechanics of fluids is a very complex science, and even scientists who study hydrodynamics for decades won't be able to tell you exactly from the look how the fin performs in dynamic conditions (we have a university professor in mechanics of fluids in our club, so I know it well). Even themselves will need to make simulations and tests in a tunnel to measure the real behavior.

Frankly told, I have certain doubts about the concept too, but am not sure at all whether the advantages overweight the disadvantages or vice versa. I'd like to see some real objective unbiased tests, but am afraid nobody really has the means to do them. However, I found it little bit too strong calling the footpockets "stupid" without even testing them. That's why I asked for the exact arguments, and whether you had personal (or second hand) experience with the fins.

 

[ILDiver]

I believe the Mustang footpocket is supposed to give better energy transfer from the foot to the blade. I've heard people say that they feel more connected to the fin with the Mustang footpockets. As for the water flow around the footpocket in your diagram, I would have a slightly different view of the effects. You show the water spilling towards the heel of the Mustang and the water flowing down the traditional pocket. Your looking at it wrong imo. The shape of the Mustang pocket allows for less resistance in a portion of the fin that is not at all involved in the propulsion of the diver. So on the mustang pocket the foot cuts through the water and the blade has much higher resistance and brings on the flex of the blade sooner and stronger. It's the flexed blade that gives the propulsion.

Also as the diver is moving forward, that spill you illustrate will be even further reduced.

I use the OMER Rekords and I love them. But The mustang footpocket looks to be the better design.

The same is seen with split fin designs, but we won't go into the efficiency of split fins, it angers traditionalists (poking fun at Jon)

 

[Shark 1980]

This picture shouldn´t be a proof ! It only had to show what I mean...
I agree with you that it is hard to say whether the advantages overweight the disadvantages, but I prefere to trust old shaped fin for now, because it works well for me.

As regards the word "stupid" I admit that it is too strong, but probably I said that because I am a little dissapointed by the dirrection which C4 is tend to last years...

 

[Mullins]

I own a pair of 80s and though they're good fins I don't think there would be much improvement over the 25s. In fact I'd like to try a pair of 25s because I think they might suit me a little better.

I used a pair of Mustang 30s on several occasions and really didn't like them. The footpockets fitted my feet well, but that was about the only good thing about them. The blades felt very disconnected from the footpockets so it was hard to tell what was happening down there, it did seem that the top part of the footpocket/blade combination was staying rigid and causing a bit of drag, while underneath some kind of activity was going on in the rest of the blade. They were too short and too wide so it was very hard to avoid knocking the blades together (I'm fairly sure they're wider than the falcons even at the trailing edge). The Mustang 80s may have been better suited for me but the width issue would still have been there. The footpockets didn't seem to allow my feet to flex properly either.

 

[trux]

Well, this is not on the original topic, but rather about footpockets, so I thought I post it here too and hope you excuse the intrusion: on the Lunocet website, there is just a new entry about the recent re-design of their footpockets. They were not satisfied with their current solution, so they searched for another one allowing both perfect power transfer and comfort. It looks like they used their experience from the cycling industry:

​

More details here: Lunoblog Blog Archive Why A Fish Need A Bicycle ?

 

[Jon]

Now, that is cool!

They make wind socks that fit over cycling shoes to make them my aerodynamic. I'm sure they could come up with something similar for the water.

Jon

 

[Shark 1980]

Hi Mullins
Thanks for your opinion.. finaly the first important message for me !
You confirmed what I guessed about Mustangs fins and what a few freedivers told me before about these fins. As regards 80´s I have decided to stay with my 25´s for now and maybe in future when my 25´s will be broken or too damaged to buy 80´s as the next fins.

So thanks for your opinion..