What is the one thing all divers, especially new ones, can do underwater to improve air-consumption, enrich their underwater experience and reduce environmental impact?
It's the same thing that enables the experienced diver to effortlessly drift ahead, while the rookie brings up the rear frantically peddling an invisible bicycle in a cloud of silt, seemingly going nowhere ... It's your finning technique, of course.
But how can a proper finning technique make tanks last longer and dives more enjoyable? One of the answers lies in maximising air supply. Propulsion during a dive is provided by the legs, most notably the large muscles found in the upper leg and bottom, your quads and gluteus. They are powerful, but oxygen hungry muscles and when worked hard, can quickly gobble up your air supply. This is why it important to use your legs as efficiently and effectively as possible.
New divers (and some not-so new too) end up bending at the knee, resulting in a bicycle kick. The kick then not only gives you less propulsion for the same energy, but also tends to send you upward, rather than forward, bringing buoyancy onto your list of worries as well. Check for negative buoyancy/over-weightedness and or a low hanging weightbelt. These can all contribute to the more erect body position that is normally associated with the bicycle kick.
For many, finning starts out with the trusted scissor kick or flutter kick. If done correctly, i.e. with more or less straight legs bending at the hip, toes pointed outwards extending the fins and churning out even, easy strokes, it is, in fact, quite effective. It also has a good propulsion-to-energy ratio. Propulsion comes from the down-stroke and the up-stroke moves the feet back into starting position with little water resistance.
It has its limitations however and is not the best method to employ when in a silty environment or in the narrow confines of a wreck or cave. Also to cover long distances in current, the scissor kick can quickly lead to exhaustion.
Arguably, one of the most efficient and effective fin strokes is an adaptation of the scissor kick, a.k.a. the frog kick. Where the classic scissor kick runs along the vertical access, the frog kick operates on the horizontal access. In other words what the scissor kick is to freestyle, the frogkick is to the breast stroke.
Dive propulsion is produced by the closing stroke, with the feet and fins position vertically, creating resistance and resulting in forward motion. A slow opening stroke sees the feet and fins return to the horizontal position to minimise resistance. The frog kick's horizontal motion further allows you to get closer to your subjects, as silting is significantly cut down and you are less likely to stab the coral beneath you so you can use this technique for gliding low over fields of delicate coral, without worrying about to much dangerous up-and-down fin motion.
It is also a useful movement in current when, having been scissor kicking, you want to rest tired muscles without going backwards. The frog kick uses different muscles and therefore allows you to continue to progress slowly and allow tired muscles time to recover.
Once mastered, a subtle reverse of the frog kick technique will also enable you to fin in reverse. A little like reversing a motorbike, it is seldom the most graceful looking manoeuvre but is necessary now and then. The key is to push water forwards with the upper side of the fins and then return the fins to the starting position with minimal resistance.
Photographers and divers who enjoy exploring the nooks and crannies of caves and wrecks will need to master reverse finning to fully enjoy their favourite underwater pastimes.
A spin off, if you would, of the frog kick technique, finning with just one leg, is called the helicopter kick. This enables you to pivot on the spot and rotate your horizontal body without swimming in a circle. In essence this means 1 fin remains horizontal in the water and the other fin works as in a frog kick causing the body to spin around on the horizontal axis so that you end up facing the direction you came from.
Both frog kick or scissor kick, can be downscaled to ankle kicks which are useful in tight spaces or for close control. In fact there is an intermediary stage of the frog kick, the short frog kick which employs more than the ankles and allows for closer control and reduced risk of kicking up silt.
In very tight spaces you may wish to make some sort of forward progress with the minimum of movement and this is where you can use your fins merely with your ankles to waft water backwards and slowly propel yourself forwards. This cannot be done for long since the feet soon tire but is perfect for the very close control in tight situations.
So despite what you might be told in the early stages of your scuba diving training, there are a number of different finning techniques and the ability to switch between them as circumstances dictate is an important part of anyone's scuba education
Once you're gliding along like you've seen your dive instructor do so often, and employing the most efficient finning technique that the situation demands, you will notice your air supply last longer. Your improved technique will exert you less, keep your heart beat down and reduce your oxygen consumption.
Silt will remain on the bottom and no corals or sponges (or other divers) will receive stray kicks of your fins. You will be able to approach areas of interest without fear of careless damage and your underwater experience will be much enriched.
All great reasons to practice good finning technique.