The Truth About Dive Fins

manatee, force fin

Are you confused by all the theories, claims and opinions about dive fins? If not, maybe you should be. Since kicking is your primary physical activity when diving, and because the efficiency of your fins and your comfort in the water affects your bottom time more than almost anything else, dive fins are one of your most important pieces of equipment. But over the years, a lot of myths and misinformation have built up about them.

We’ve been designing and making improvements to fins for over 35 years, with millions of satisfied customers, and many major product design awards under our belts, we can honestly say that we are the experts in fin design.

That’s all we do, and we think our innovative fins are without equal in terms of comfort, efficiency, durability, performance, versatility and sheer value for your money. We pioneered fin colors, extended heel sections, leading edges, water channeling and accelerating through a split-V shape, fin, adjustability, flexibility, and the use of snappy and high performance materials, such as polyurethane. Just about every change and development in the way divers think about moving through water today came from Bob Evans and his Force Fins.








best fins for underwater photographyIf you’re used to traveling, packing, and lugging around two huge fins, get ready for a surprise when you take along Force Fins. They weigh less than 2 pounds each, are easier to handle, take up less room, fit in carry on luggage, are easy to get on and off, and you can even walk forward in them!

How well you move through the water is based on many factors including your kicking style and individual characteristics like leg strength and ankle flexibility in addition to your choice of fins. In the underwater world, you need all the help you can get, and we know that you want fins that are comfortable, efficient, durable and reasonably priced. That’s why we invented Force Fins.

jump with fins, force fins, military fins, what fins do Navy SEALS wearAmong those divers in the know, Force Fins are a closely held secret. Dedicated Force Fin users are a special group of divers who were willing to try a revolutionary diving product that delivers on its promises. They will never go back to other dive fins again. Would you like to join this elite group? We could go on forever describing the unique benefits of using Force Fins, but there’s only one way to really find out why our fins are the best diving fins in the world: try a pair. You’ll be happy you did.


Flutter, The Most Efficient Kick For The Most Efficient Fins


Since the kick is all that divers have to propel themselves, it’s important to do it correctly. Many people believe that divers should use a flutter kick that is deep or wide and slow and pushes water backward. But scientists studying animal locomotion along with swimming theoreticians discovered more than three decades ago that this simplistic “drag-dominated” propulsion theory (the movement of a canoe paddle is an example) does not tell the whole story of how boats, people and most animals move through the water.

Based on a more sophisticated understanding of fluid dynamics and bio-mechanics, we now know that other hydrodynamic forces such as “lift” propulsion are just as important and in many instances, more important in propelling you efficiently when kicking.

Force Fins are designed to use this more efficient kick style with its lower energy cost. how to kick force fin, divers kick, scuba kick, flutter kickNotice how streamlined this diver is. Her kick is no wider than the profile of her tank on her back and her bc in front.

Take a look at how animals do it. Contrasted with the inefficient pushing-backward paddling of ducks, energy efficient fish beat their tails side to side (or up and down in the case of marine mammals like dolphin) in a flapping motion, using a complex mix of lift and drag forces to overcome the resistance of the water and move forward.

The best way for humans to perform a flapping-style kick is not with a deep and slow kick, but with a shallow and quick motion that’s more streamlined, more energy efficient, and that consumes less air. Of course, some types of fins are better suited for this kind of kicking than others. Force Fins are designed to use this more efficient kick style with its lower energy cost. Our fin generates maximum thrust from minimal vertical movement because of its superb channeling ability, and the rate or frequency of the kick is easily increased because of the recoil and snap of the blade that speeds up the fin’s recovery. The snap of the blade feeds energy back to your muscles, increasing your efficiency and bottom time while propelling you forward.




Fin Propulsion and Force Fin’s Efficient Kick

Populsive Divers Kick, Efficient Kick

Divers propel themselves by moving their legs (and the increased surface area of their fins) back and forth against the water with a flutter kick motion. This kicking results in a complex combination of propulsive forces that move the diver forward as well as resistance or drag forces that hinder that movement.

With other fins, virtually all of the propulsion comes from the downward phase of the kick (imagine you’re horizontal in the water with your stomach toward the bottom) and almost none on the up-kick. You can test this yourself in the water by trying to kick up, with or without fins. You’ll go nowhere. But simply extend the lower leg down and watch yourself move ahead.

Force Fin KickOne reason for this uneven propulsion is that humans naturally have more strength when kicking down. The power or downward phase of the kick emphasizes the powerful quadriceps muscle group at the front and side of the upper leg. The kick’s upward phase uses the weaker hamstrings at the back of the thigh and is mainly a recovery movement setting up the leg for the next power phase. The result is a natural two-stroke kicking cycle of power and recovery for each leg. It’s the same with other continuous activities like running, bicycling or swimming where a power/recovery cycle is built-in to conserve your energy.

While most other fins make you work just as hard on the recovery as on the power phase, Force Fins take advantage of this two-stroke cycle and work in harmony with the body’s natural strength. The flexible blade of our Force Fin opens out to its maximum surface area to move a high volume of water during the powerful downward portion of the kick.

During the recovery, the blade folds down, channeling water behind while limiting resistance to conserve your energy. (If you have to put the same amount of energy into both parts of the kick, you fatigue much sooner.)

As you kick down, the blade opens out to its maximum surface area, engaging the muscles of the whole leg to push water and provide initial forward thrust.


At the end of the downstroke, the fin recoils, setting up to rebound to its original position during the recovery or return kick stroke.


The fin then rebounds to help begin the upward recovery phase of the two-cycle kick stroke.


The fin’s tips fold inward to aid the upward recovery and to prepare your leg for the next downward power stroke.


Force Fins are the only fins that provide propulsion consistent with your natural two-stroke kick cycle to this degree. By providing for more of a separate power and recovery phase, oxygen depletion is reduced, and the onset of fatigue is delayed. The result is that divers can kick continuously for longer periods of time.


Powerful Fins, Are They the Best Fins?


powerful fins, navy diverOne of the biggest areas of confusion regarding fins is the notion of “power.” Many divers believe that the more they can feel their fins, the more they’re getting out of them. And to capitalize on this belief, many fin manufacturers have responded by making longer and stiffer (more “powerful”) fins that fool divers into thinking that they are generating more propulsion with less effort.

However, the laws of physics don’t agree.

You are the power for your forward movement, the more you can feel your fins, the more energy you’re expending and the more you’re working for them, instead of having your fins work for you

“Power” is a measure of energy expenditure. More power requires more energy, and more energy requires more effort, not less. A 100-watt light bulb is more powerful than a 60-watt bulb. It puts out more light, but it also uses more electricity and costs more to operate.

The same with fins. What divers believe to be power in fins is really resistance. That’s what you feel. “Powerful” fins rapidly waste your energy supplies and actually transfer a much smaller percentage of the effort into forward propulsion than you think.

Since the name of the game in diving is to decrease energy use (which decreases oxygen consumption and increases bottom time), it makes sense to use more efficient fins, not more “powerful” ones, as long as they do the job of moving you through the water.

The fact is, no fins have power. You are the power for your forward movement, the more you can feel your fins, the more energy you’re expending and the more you’re working for them, instead of having your fins work for you. Force Fins are specifically designed not to be felt; Force Fins are designed to work efficiently for you.Extra Force Fin, Powerful Fin

And, for those of you who still want “power” our EXTRA FORCE FIN is the best fin.

The Extra Force Fin has the largest surface area for extra leverage under load. The way Master Fin Designer Bob Evans puts it, “You don’t fly a learjet to carry a herd of elephants. You fly a 747 or C130. The EXTRA FORCE FIN is our C130.