Best fins to push a beastly rebreather

[The Kraken]

The one thing that subjective diver tests cannot set as a control is the individiual physical conditioning of the diver or divers doing the testing.

Even using just one diver to do an evaluation of several different fins is not controllable because of the possibility that the testing diver peak physical cannot be guaranteed to be equal for each test.

I'm sure some agency out there has some sort of mechanical device to which the subject fins could be mounted that would allow a controlled measure of the force output as a percentage of the force input. Those tests I would have a tendency to believe.

 

[silent running]

Hello teksimple, it seems to me that even the best fins advantage can be cancelled out by poor fin technique. This not to imply that you have poor fin technique-it's probably better than mine-it's just that the difference between the best fins and the next level down, is probably pretty minimal. So any lack of efficiency could easily render the advantage nill. As for me, my CCR-a Prism-is only 47lbs, so my standard recreational Mares Quattros work fine. It seems all the tech divers I know prefer stiffer fins and I find it hard to imagine that any split fins can be made as stiff as a standard fin blade, due to their physical structure. I've never seen any fish with anatomy that actually looks anything like a split dive fin either. So I remain a skeptic. And while we're on the subject, I am curious if anyone has an opinion about whether full foot fins are more efficient than the same fin design made for use with boots/straps.

 

[teksimple]

And while we're on the subject, I am curious if anyone has an opinion about whether full foot fins are more efficient than the same fin design made for use with boots/straps.

Some open heel designs will be more efficient of course, but the swimmer will often notice it right away. As a dive instructor in Hawaii I have compared various designs of Mares and Cressi fins in open heel and full foot design, and the difference is very obvious to me. There are probably other opinions on that subject, but you can't argue with the laws of physics. An open heel fin worn with booties and straps will ALWAYS have less efficiency than the same full foot design.

Some loss of efficiency comes from the use of booties themselves. Movement of the foot is not transferred perfectly to the fin because the booty compresses, and not an insignificant amount of heat energy replaces that which would normally be transferred from the foot to the fin. Other loss of efficiency comes from the hydrodynamic drag of the larger foot pocket and cavity, and straps.

 

[DiveTub]

Like Silent Running I too use the Mares Quattros, they are a strong fin for a strong leg. And I would not put them on small skinny boys and girls.

A little test I was told about to figure out a fin that works well for pushing alot of surface area (such as a rebreather) through the water.
Grab your self a decent size square piece of plywood
Jump in the pool and hold it in front of you, arms streached out vertical so you are pushing it through the water get your bouyancy right and start finnning at a constant rate.
Now time how long it takes you to swim a lap and how many fin cycles, try this with various fins, give them all a good 5 or 6 runs and do an average on the time and fin cycles.

From what I found the Quattros and beat every split fin we tried, the problem we found with the splits is when you put a decent load on them the split spread to far apart and just lets the water pour through the gap without giving much power, they did work well when not pushing any load such as a little 85cft tank.

After 10 years with the same pair of Quattros I will not be swapping over just yet.

Cheers
Chris

 

[teksimple]

Grab your self a decent size square piece of plywood

Very good idea! I bet that none of these split-fin companies have tested with a plank for hydro resistance!

I am sure I I will get plenty of looks if I try that at one of the pools here in Baghdad. I get enough looks from the soldiers when I just wear swim goggles. But what the hell.

 

[Poogweese]

Has anyone else had any experience in heavy currents, a big rebreather, and split vs. free diving or other fins?[/QUOTE]

I continue to use my scubapro jet fins, they're comfortable and I can scoot when on my Dolphin, steel 100, or double 63's. I tried the scubapro splits (the grey ones) and didn't like them, they just didn't have the "feedback" resistance that I was used to. Hope this helps with your question.

 

[silent running]

Thanks for the info Teksimple. I want to try some full foot fins, but I'm afraid of slipping on the boat deck with all my gear on in my bare feet. Does anyone know of a thin neoprene sock or some other material, with some texture on the bottom to prevent slipping?

 

[teksimple]

Thanks for the info Teksimple. I want to try some full foot fins, but I'm afraid of slipping on the boat deck with all my gear on in my bare feet. Does anyone know of a thin neoprene sock or some other material, with some texture on the bottom to prevent slipping?

Funny that you mention that. I just bought a new pair of Aeroskin of California TK76 fins socks that has the thin Kevlar/Neoprene sole. Great fin socks and they don't slip. I use the socks more to prevent chafing, than slipping with bare feet. I recall slipping more with booties in the the last 21 years of diving on boats than I ever have with bare feet. But certainly the PLAIN lycra/polartec fin socks would make you slip. Note, fin socks work great for warmer waters, but if it gets much below 60 F, you may have a problem.

Call Aeroskin of California to find a dealer near you: 800.368.9255.

 

[scubanimal]

Has anyone else had any experience in heavy currents, a big rebreather, and split vs. free diving or other fins?

My video camera rig has a lot more drag than my dolphin so I too have noticed a big difference in fins. If I expect to be in a cold water current I use my JetFins, Atomic Splits for normal dives, but if the water is warm (e.g. not around here) then for heavy current I like free diving fins. I've been in severe currents and had to run back up current to retrieve gear and found those things to be amazing. Pain in the tail for getting close for photo shots ( foot heavy so too easy to bump the reef) but outstanding for sure fire upstream progress.

my $ 0.02

 

[caveseeker7]

I'm pretty sure Pawel's Bazooka generates more drag than his fairly large Azimuth.
Just the guy to talk to.

By the way, he has some "Aliens of the Sea" clips on his website , Check it out.