Modified Flutter versus Frog Kick (from a different point of view)

[-JD-]

I just spent a 16-dive Blackbeard's trip with my Force Fin Pros over Altama Maritime Assaults.
Except for "get there fast mode" times where I was fluttering. I mostly used an ankle flip frog kick to maneuver around. I was floored at how easy and efficient it was. The shorter FFs make that easy to maintain compared to my Eddys and Slipstreams which need larger-muscle involvement.

 

[lowwall]

I just spent a 16-divd Blackbeard's trip with my Force Fin Pros over Altima Maritime Assaults.
Except for "get there fast mode" times where I was fluttering. I mostly used an ankle flip frog kick to maneuver around. I was floored at how easy and efficient it was. The shorter FFs make that easy to maintain compared to my Eddys and Slipstreams which need larger-muscle involvement.

I think alternate kicks is why @Bob Evans made the Pros. I like them too.

 

[Doctor Rig]

I think alternate kicks is why @Bob Evans made the Pros. I like them too.

I sure would like to try the Force Fin!

 

[-JD-]

I sure would like to try the Force Fin!

I will probably be wearing some FF variant at the Coz Invasion. If fit works we can make it happen on a shore-dive ...

 

[lowwall]

I sure would like to try the Force Fin!

I got mine used. They are basically indestructible so the age doesn't matter. Straps might degrade, but you can buy them or a bungee kit new from FF or jury rig something. They pretty much stay on your feet even without the straps so it doesn't have to be perfect. SCUBA Archives - Page 2 of 2 - Force Fin

But make sure you get the FF Pros instead of the originals if you want to do anything other than flutter or dolphin kick. They are the same shape, but are stiffer. Apparently the more exotic options like the Excellerating and Extra are even better, but it's unlikely you'll find them used and the new prices are eye watering. SCUBA Archives - Force Fin

If you borrow some, the problem is one dive is unlikely to be enough to decide whether you like them. They feel really different and it seems like you aren't moving much water. I had to do some timed tests in a pool versus my regular fins to overcome this first reaction.

 

[Doctor Rig]

I will probably be wearing some FF variant at the Coz Invasion. If fit works we can make it happen on a shore-dive ...

That would be great! You should be easy to find. I’ll be looking for you.

 

[Gandalf-the-Diver]

Hint, there is a "flick" of the ankle that has to happen at the right time during the kick cycle and it gets you insane amounts of power for almost no effort but it has to occur at the right time during the stroke.

I have tried to keep up to people who know how to do that "flick". Tried, being the operative word.

 

[Doc Harry]

Years ago I did my own underwater study of the efficiency of various kicks and speed.

I set up a 100-yard underwater course with cave line, and did laps using a variety of kicks and speeds, all the while recording my lap times, kick types, gas consumption, and speed.

I based my speed on my perceived exertion, i.e., relaxed, mild exertion, moderate exertion, full speed.

As expected, I found that a slow, steady speed was much more gas efficient than a more rushed pace. This has implications for cave divers.

I also found that a slow, lazy flutter kick was more gas efficient that a frog or modified frog at the same speed.

In my experiment, "gas efficiency" was defined as gas consumed (cubic feet) per unit distance traveled.

I prefer the modified frog in caves because it gives me infinitely more precise control than the flutter. But if I am in wide-open passageways, I will switch to the flutter for gas efficiency.

 

[inquis]

I based my speed on my perceived exertion

I've done similar and figured out the "flick" for the mod. frog. On my ToDo list, however, is to repeat while maintaining a consistent speed (e.g., 30 fpm) with a line and markers for intermittent feedback to reduce the variability & subjectivity of perceived exertion. I might also investigate/optimize the "duty cycle" between kick & glide on frog kicks (e.g., hard kick/long glide vs medium kick/shorter glide).

I can't imagine how moving my entire shin/foot is more efficient than the flick of the ankle for modified frog. Much of the frog efficiency comes from allowing the fin flex/rebound return the energy back to the water, but that's reduced as soon as you move the heel rearward with the mod. flutter.

 

[lowwall]

I can't imagine how moving my entire shin/foot is more efficient than the flick of the ankle for modified frog.

Drag. If you are moving at all, the frog kick blade path results in much higher drag than flutter.

Much of the frog efficiency comes from allowing the fin flex/rebound return the energy back to the water, but that's reduced as soon as you move the heel rearward with the mod. flutter.

I don't know what "return the energy back to the water" means. Frog's perceived efficiency is almost entirely a byproduct of its low speed. Throttling flutter back to frog speeds results in greater efficiency.

Frog kicks does have advantages, but efficiency is not one of them.