Snorkeling equipment: fins

September 18, 2023

The third indispensable element! Your engine, your seven-legged boots! Two imperatives: comfort and efficiency.
A fin is made up of a foot part and a blade.
Fins are called "shoe" or "adjustable". The former are "closed" and correspond to sizes. Adjustable fins remain open at the heel and have a strap that grips the back of the ankle. They are generally less comfortable and offer lower performance.

Adjustable fins

Let's take a look at footwear.
Today's footwear is often of varying thicknesses or made of rubber of different hardnesses: the harder to transmit force (underside of foot, side rails, upper end above toes), the softer to ensure comfort (instep and ankle).
The footbed must be soft and comfortable, yet snug and rigid enough to transmit the force from your foot to the canopy.

Adopt a comfortable position and wet the shoe and the shoe part of the fin.

Press your foot firmly into the bottom of the fin before slipping your heel in.

The junction between the foot part and the blade must be as wide as possible, to ensure efficient transfer of the force of the stroke.
The blade is the mechanical element that restores the force stored by the fin and transforms it into a propulsive wave.
The blade must be elastic, flexible and rigid at the same time. Like a leaf spring. If it's too elastic or too flexible, it won't be very effective. If it's too rigid, it will cramp more easily and won't allow for satisfactory finning.
The presence of spars on the side of the fin channels the flow of water and prevents propulsive energy from being dispersed.
Longitudinal ribs or channels on the fins play the same role, preventing the fin from slipping sideways. Finally, some fins feature flexible rubber channels. The aim is the same: to channel the flow of water caused by finning and direct it backwards to promote propulsion.
Some fins, known as "openwork", have a hole to facilitate penetration into the water, for less effort. They are designed for beginners and those with little training. They make it easier to learn, without the risk of fatigue, pain or cramps.

An openwork palm.

The whole fin must be light. The flexible blade has a perceptible spring effect when the fin is bent.
The shoe and blade assembly must be rigid enough to hold together.
There is no such thing as the ideal fin. It all depends on your stature, strength, physical condition and intended use.

The booties slip on under the wetsuit.

Wearing neoprene booties protects your feet from the blisters and irritations that can result from a too-rigid footbed. The liner shouldn't be too tight, so as not to impede blood circulation.
When slipped into the flipper, your foot should be held in place, not squeezed. Depending on the thickness of the liner, choose one or two sizes larger than your own.
Fins are a little outdated, but so effective. These are rubber straps that hold the foot in the fin: in front of and behind the ankle, and under the foot. No risk of slipping off and a better hold for the foot in the fin.

The authors

Snorkeling guide

Emmanuelle Levasseur, Julien Collet