Propulsion techniques are a bit like a toolbox: you wouldn’t expect a workman to turn up with only one tool for the job. Similarly, successful technical divers need more than one way to move underwater. We’re taking a look at propulsion techniques and their applications here.
We can forgive new divers for never having thought about how they move underwater. After all, propulsion techniques are not part of the standard open water diver curriculum of all agencies. However, when you move on to more challenging dives or want to become a technical diver, mastering different propulsion techniques becomes important.
Propulsion: a fundamental skill
Like buoyancy control and trim, propulsion is one of the foundational diving skills for technical divers. And, just like buoyancy and trim, propulsion does not exist in a vacuum. If you cannot hold a set depth by controlling your buoyancy with a combination of wing and lung volume, you won’t be able to focus on how your fins are moving.
Without horizontal trim, even a perfectly executed backwards kick will either send you up or down. Kicking up or down means having to readjust your buoyancy frequently, causing additional task loading. However, if you can get these three to work together, you are well on your way to managing multiple tanks, gases and tasks.
The frog kick
Most tech divers start with a frog kick. In principle, the frog kick is similar to the movement you make when swimming the breaststroke. The knees and ankles and some degree of leg extension drives the fin blade, but it’s not always necessary to fully extend your legs. This kick is a tech diver’s ‘bread and butter’ kick, which they’ll use for a majority of each dive.
The modified flutter kick
If your legs tire from repetitive movement, but you still need a similar degree of propulsion, the modified flutter kick becomes an option. Technical divers generally want to avoid stirring up silt from the bottom of the sea, wreck or cave they are diving in, so this altered version of the kick works without fully extending your legs. Full extension of the legs would create a draft, pulling up sand or silt. Instead, tech divers extend their ankles and point their fins upward before flexing their ankles to allow the fin blade to push the water behind them. The kick feels very strange initially, but you can actually use it to build up a lot of power and speed to help you move through a current, for example.
Modified frog kick and shuffle kick
On the subject of modified propulsion techniques, there are also both a modified frog kick and a shuffle kick. They are essentially smaller, and often slower, versions of the frog kick and the modified flutter kick. We use both the modified frog kick and shuffle kick for controlled movements in restricted areas. They are essential for cave and penetration wreck dives to zero-visibility situations. For both, movements are largely restricted to the ankles. Knees and legs stay almost motionless and at a 90-degree angle. The ankles create enough movement to drive the fin blade.
These are not fast kicks, and they are not designed to cover large distances. They are all about controlling your movement and are useful outside of overhead environments as well. During photography dives, both of these propulsion techniques are very useful when it comes to nearing marine life without disturbing it. Both kicks are ideal for sneaking up on whatever it is you would like to photograph.
Having moved close to where you need to be, it’s also important to be able to move away — ideally without using your hands to skull. This is where the backward kick comes into play. For some, it’s more or less the Holy Grail of propulsion techniques, having taken dozens of dives to master. For others, it comes naturally. All technical divers must master this kick. When moving forward and encountering an obstacle, for example, you first backward kick is effectively your brakes, stopping the forward movement. Your next few backward kicks then allow you to back away from the obstacle.
It’s also handy to know how to move backward when gas sharing. The out-of-gas diver signals his team and a teammate moves in quickly to supply gas. To avoid crashing into each other (while holding torches, controlling reels, etc.) both divers can simply kick backward to give each other a little space while staying close enough to share gas. In open-water environments, the backward kick is ideal when divers are adjusting their position within a team. Anyone who has ever done a fast drift dive along an undulating wall will appreciate the ability to adjust the way they are facing with a swift and powerful backward kick.
The helicopter turn
The helicopter turn is another way to turn around. The name is a giveaway: this kick allows you to turn around — 360 degrees if necessary — without taking up more space than your own length. While you can push around with one leg only doing a semblance of a frog kick, the helicopter turn is smoother, more efficient and a lot more controlled when both legs fin together. In that case, one leg would perform a motion similar to a backward kick to steer and the other performs a version of a frog kick. Most divers will have a favorite direction in which to turn; what’s important, though, is to master this kick in either direction to complete your toolbox.
Fin choice and propulsion techniques
A word on fins: typical tech diving fins with relatively short, rigid blades will make these kicks easier to master and give the diver much better control underwater. That said, many other fins will work, but may make mastery a bit more difficult. Generally speaking, split fins or long freediving fins will make things harder and, when problems occur on technical dives, additional task loading will make it harder to solve anything.
So, how do you master these propulsion techniques? Practice, practice, practice. Dry practice will help teach your ankles, knees and legs how you want them to move, and this is something any diver can do at home. Then, in-water, apart from a solid demonstration and practice time, getting video feedback also makes a difference. Seeing what you are currently doing goes a long way toward adjusting, and eventually mastering, whichever propulsion technique you find trickiest.