SAC using frog vs flutter

[747pilot]

I'm not DIR so please excuse the ignorance but why do divers use a frog kick in an OW environment. I know about not stirring up the bottom but that can also be accomplished with a slightly higher dive off the bottom and by being careful. So I'm thinking that maybe it has to do with SAC. I currently use Bio fins and was wondering if anyone had done a comparison with Bio's and flutter kick SAC vs Jet's and frog kick. It would seem that if the divers trim was horizontal and using the flutter kick then the legs wouldn't be sticking up in the "slipstream" and causing drag. Anyone have an explanation? If so, some SAC numbers would be appreciated. Then again maybe I'm making the wrong assumtion. Thanks.

 

[TSandM]

Well, I don't know about scientific comparisons, but my SAC rate before and after learning the frog kick hasn't changed.

However, my husband was swimming about six or eight feet off the bottom today, using a flutter kick with split fins, and was sending up a small plume of silt with each kick. So you have to be awfully far off the bottom to avoid disturbing it with a standard flutter.

I find the frog kick restful, because it's kick and glide, kick and glide. But that doesn't really show up in my SAC rate, which was pretty low to begin with.

 

[stiebs]

The only time I ever use a flutter kick is if I want to get somewhere fast. I find a rog kick much more natural and more relaxing. Plus if I'm diving in a group I always tend to find myself waiting for others. Flutter just send me off too quickly.

 

[Adobo]

I'm not DIR so please excuse the ignorance but why do divers use a frog kick in an OW environment. I know about not stirring up the bottom but that can also be accomplished with a slightly higher dive off the bottom and by being careful. So I'm thinking that maybe it has to do with SAC. I currently use Bio fins and was wondering if anyone had done a comparison with Bio's and flutter kick SAC vs Jet's and frog kick. It would seem that if the divers trim was horizontal and using the flutter kick then the legs wouldn't be sticking up in the "slipstream" and causing drag. Anyone have an explanation? If so, some SAC numbers would be appreciated. Then again maybe I'm making the wrong assumtion. Thanks.

There are actually at least two separate and distinct questions here, right? First, why do some divers opt to do a frog kick when there is little danger of silting? Second, what is more efficient (thus lower SAC rate), frog kick with jets or flutter kick with Bio fins? I don't have an answer for either question but I think it important to understand that these are different things you are asking about.

One thought on the second question... I would suggest that it is not as simple as frog kick with jets vs flutter kick with bio fins. I think you might have to look at the whole package when trying to understand which is more efficient. In other words, it might be more useful to compare a DIR diver (and all that implies) frog kick in jets vs. "personal preference" diver (and all that implies) flutter kick in Biofins.

Edit: One other thing to consider here. It is a fact that you can use jets to do things like helicopter kick and back kick. If for the sake of argument you agree that biofins (and any other split fin) do not allow the diver to employ other propulsion techniques other than forward propulsion kicks, then there are other "efficiencies" than jetfin divers have to their advantage that is not at all reflected in any "go from a to b as fast as you can" test.

 

[Dive-aholic]

I'm not DIR, but I do frog kick. Once you frog, it's hard to go back to flutter. To me, it just seems more natural to frog than flutter now. In fact, if I have to demonstrate a flutter to students, I really have to concentrate on it to get it right. Also, as TSandM pointed out, even when you're off the bottom a few feet, you can still create silt clouds with the flutter. You'll never create silt clouds with a properly executed frog kick. As for creating drag. I find that I am more efficient and move along better with the frog kick. It's the kick and glide action. You're moving your legs less, which in turn creates less resistance. With the flutter, most people do a continuous flutter rather than a kick and glide. This increases resistance and air consumption.

 

[grazie42]

For the two to be perfectly comparable you´d have to do 2 dives at the same speed. Getting a "scientific" comparison would be very difficult, IMO. Also, you´d propably be so focused maintaining speed and depth that it wouldn´t mirror a "real dive" anyways.

For me the frog is more suited to the slow, mellow diving I do. For me it also helps with "buddyskills" as I make sure that I, at least during every "kick", look at buddy and surroundings to make sure "everythings ok"...

I´d also disagree, a bit with adobo, it seems like the OP is interested in the frog and jet vs. flutter and splits part of the equation...

 

[Ben_ca]

why do divers use a frog kick in an OW environment.

Like Lynne and the others have stated even in OW there's a problem with unconsiderate/unknowing diviers silting up the site.... Maybe they never look back and see that they're leaving behind big plumes of silt.

We saw that yesterday with flutter kickers rototilling around the breakwater... Besides with the Frog kick and Jet fins then youcan learn the Helocopter, back and other kicks for your tool box

 

[Charlie99]

I'm not DIR, but I do frog kick. Once you frog, it's hard to go back to flutter. To me, it just seems more natural to frog than flutter now.

Same here. I was frog kicking long before I ever heard the name or saw it described. Having tried a lot of different kick styles I found frog kick the easiest and just naturally migrated to that style of kick. When puttering around the reef I use an even more efficient kick method, which is similar to a frog kick, but legs remain fully extended and streamlined, and the power from the stroke comes from the ankles. Sculling might be the term. Sculling might not work with the smaller area fins like Jetfins, but are nice with original Blades from U.S. Divers.

 

[Adobo]

I´d also disagree, a bit with adobo...

Well, you would not be the first to make that mistake. Okay, just kidding.:14:

 

[Charlie99]

We saw that yesterday with flutter kickers rototilling around the breakwater...

The problem I see is not due to flutter kick, but instead because many new divers are negatively buoyant, angled head upward, and kicking downward to maintain depth. They'd be silting with a frog kick too.