Why we don't always use freediving fins in scuba?

There should be no problem with indiscriminate kicking of the bottom with freedive fins.

The video shows, possibly without you realizing it,,, the way that freediver fins(or any fins) are used close to the bottom without destroying the visibility (or damaging coral). All that is required is to keep the knees bent at 90 degrees. This keeps the fins a foot or so off the bottom and allows the diver to gently kick and move and maintain stability.

Freedive fins provide efficiency and a ton of control in the water column - they aren't necessarily used to swim faster.

Also the comments that freedive fins are stiff and super powerful and are therefore too tiring for "normal" divers is off the mark as well. There is a broad selection of fin stiffness options when you move into the more expensive fiberglass blades, for example. If you want a soft blade, you can buy one.

 

Using freediving fins for scuba.

People who need or like to cover a lot of ground may find freediving fins useful. Some Southern California lobster divers like them. I’ve seen those same guys go without BC’s and they use huge tanks.
Their goal is to cover a LOT of ground as rapidly as possible, so the idea would be something like a race car with a huge powerful engine that is high geared (big legs and long powerful freediving fins), and as little drag as possible (aerodynamics with a sleek car body, or in the case of water, hydrodynamics with sleek wetsuit and no BC). Those guys (and girls) are also very competitive with each other.

I’ve used freediving fins for scuba but I found it to be probably more of a pain than it’s worth where I dive. I’m in and around rocks a lot looking for game and scallops. I prefer shorter fins for maneuverability and ease of donning doffing on shore dives. I’ve had open heel freediving fins but I didn’t like the heel movement and felt they were too sloppy. The long fins I have now are full foot and I have to wear neoprene socks. That also makes it a pain for shore diving because walking in them ruins the bottom.
The last time I used my long fins was for freediving when abalone was still open.

One more point about freediving fins for scuba.
If you have a lot of heavy dragging gear on like a baggy drysuit or a puffy jacket BC, or both, you will wear yourself out trying to push all that through the water with freediving fins. There is a trade off, one good stroke with freediving fins can be like two or three strokes with short fins. The shorter fins are “lower geared” where as the freediving fins are “high geared”.
If you’re going to use freediving fins for scuba you need to minimize drag by really thinking about things that stick out and catch moving water.
Sleek freedivers have the slickest profiles of all, so they can slip through the water very quickly and efficiently with powerful long fins. They will position their bodies and even head angle to pierce the smallest hole they can while gliding through the water column. When you start adding scuba gear and introduce things that stick out and interrupt that sleek profile it will slow you down and thus cause you to work harder to overcome that drag. This is where you need a lower geared fin so you can get more (but easier) kick cycles to move forward. The extreme example would be excessive drag caused from an overstuffed BC, hoses sticking out everywhere, bad trim, overweighted making the wing overinflated, dangling console, and an out of shape diver. I’m starting to think split fins were invented to address this type of situation!

 

Eric makes some good points, but I think a lot of people don't realize where these "freediving fins" originated. It was not with freediving; it was from finswimming and underwater orienteering competitions. After proving their merit, before monofins took over, in finswimming, freedivers adopted them too. Now, they are used whenever people like the ability to move quickly in the water.

Freediving Fins use a different theory for moving water. Whereas regular Scuba Fins, whether they are vented, straight-blade, or cupped form a "J" in the water, freediving Fins tend to form a "S" shape in the water. This is much like how an eel swims. If you look at the top and bottom of the stroke, you can usually see this "S" shape. For finswimming competitions in the 1960s through the 1980s, these "bifins" were hand made in Eastern Block countries from fiberglass. The fiberglass available there and then could be sawed to the shape desired, and layers peeled off to "taper" the flexibility of the long blade. In this manner the individual finswimmer or underwater orienteer could completely customize the fin to his or her own desires.

Now, these Fins are commercially made, with variations of the blade available to the freediver. (They are also really expensive.) But, they ar also very efficient and comfortable. In the 1980s I used a commercial variety made of rubber for an 18 mile Finswimming event on the lower Umpqua River, where I was the only finisher.

SeaRat
John C. Ratliff
Former Finswimming Director (1980s)
Underwater Society of America

 

Thanks John
Many of your posts bring both historical remarks on scuba/freediving and your knowledge of the technique and theory of the 2 sports. Like in this one, not only you show that you know the origin of this type of fins, but why that origin explains the way they work and its implications for scuba. I always read your posts with great interest

 

This thread brings to mind one of my (few) threads from a couple of years ago. I just reread my old thread. There is a lot of info there: Tech with Freediving Fins.

rx7diver

 

Freediving fins are very effective for pure drift diving (@Ana, @CuzzA), but are especially good for hunting. These are the fins of choice for a lot of hunters and dive guides in southern Florida (diving from a boat). The power transfer from the full foot pocket is great. However, as stated earlier by @Eric Sedletzky, full foot fins are not so great for shore diving. Against the repeated protestations from the wife, I took freediving fins to the iron shores of Bonaire. I had to wear sandals to negotiate the sharp volcanic rock down to the water (yes, I am a wimp), so that was a huge PITA. Considering the currents in Bonaire are typically nonexistent, these fins were certainly overkill. Most of the time my fins were up to protect the reef (see pic). So like @NorCalDM said, “different tools for different jobs”.

 

One thing I have wondered about: How do freediver fins work for surface swimming? Imagine that you have to surface swim an appreciable distance (say, 0.5 miles) in full gear with full cylinder, using your snorkel, to the spot where you are to commence your descent. Will freediver fins work for this? If so, then how well (compared to, say, Scubapro Jet Fins)?

rx7diver

 

horses for courses.

 

I usually swim on my back when surface swimming so the length of the fin does not matter to me. When using my freediving fins I'm just a little more upright and it's no big deal. But no matter what I wouldn't want to swim .5 of a mile I'm taking a boat!