While I agree with you on some of this post, I must caution people that trying to determine which fin will take you farthest on a single breath of air is a very dangerous undertaking, and an open invitation to shallow water blackout. This is why the World Underwater Federation decided very early on to hold apnea competitions (breathhold underwater swimming) only at the 50 meter distance. So I would tell people not to try swimming for distance, records, etc. on a single breath of air.dumpsterDiver:
I don't know whether you have tried finswimming for time, but believe me these guys and gals are very interested in efficiency. This includes body technique for streamlining, placement of the head, use of goggles or no visual aid at all over the eyes, and of course the type of fin. Finswimmers up until very recently home-built their monofins, and there are no restrictions on the fin under CMAS rules, only that it attach to the feet.
Concerning air consumption, fin swimmers take that to the extreme too, as the other underwater swimming events for time are 100m, 200m, 400m, and 800m, using a hand-held scuba. They minimize the tank size, practice streamlining technique with the tank, practice racing dives with the tank held in front of them, and try really hard to keep their bodies at maximum efficiency while consuming the least amount of air.
Concerning fins, I have a lot of comments (perhaps more than this thread can endure). So I will keep it to a minimum. I found the thread to leaderfins today, on a Google search to find current world record times for the 50m apnea. My material dates back to the 1980s when I was Finswimming Director for the Underwater Society of America before Mike Gower took over from me. I've never used these Leaderfins, but their website looks interesting. I had a Dolphin monofin, and found the foot pocket uncomfortable, and sold them. I now use a Finis monofin (the training monofin, that isn't quite so wide). It is adequate, but foot pockets still need improvement. Going to a monofin is quite an adjustment, and takes awhile to pick up the modified dolphin kick required by this unique fin.
On the Vintage Scuba Supply thread (see above), I've shown an experiment I'm doing currently with three full foot fins, all three almost identical except for the fin style (one paddle, one split, and one a modified scoop fin). To me these show that the scoop fin concept is better than either of the two, but doesn't compare with the monofin simply because of surface area and efficiency of the monofin. Split fins loose some propulsion efficiency through the split, and that's the advantage of the scoop fin concept.
There is much more to learn about underwater swimming than anyone here probable thinks about, and I've been experimenting with different techniques for over 20 years now. Enough for now, but I'll be back later.
SeaRat
