Leaderfins 20 and 33° blades

We have already presented the extremely interesting fins offer by Leaderfins. In particular, we have analyzed the difference in the blades made of different composite materials. We have presented the 100% glass fiber (named “fiberglass“), a sandwich mixture of glass and carbon fiber (named “carbon fiber“) and the 100% carbon fiber solution (named “carbon“). This is already a very complete offer by the Estonian company. In addition to this the value for money is great! But there is more to the Leaderfins offer. The Leaderfins blade angle of 20° or 33° is available on the glass fiber and pure carbon blades. On the carbon fiber/sandwich models only the 20° angle is offered at the moment.

The pluses
The increase in the Leaderfins blade angle compared to the foot of the spearo or freediver is thought to indulge the natural position of the ankles. With a high angle the ankles of the diver can evidently keep a much more relaxed position. This will be closer to the angle (not quite of course) that we normally have when walking. In fact, in such situation, the angle of the ankle is much closer to 90°. When finning the need is to open such angle of the ankle to have the blade working more parallel to the body position. In such way, the blade can load a good quantity of water, bend and push the water backward.

For the law of physics, the mass of water moving backward will push the diver forward. This solution also avoids the initial part of the blade, in front of the foot, working horizontally. Such action simply moves water up and down and increases effort, but generates no additional thrust. This is true especially in the positive kick (forward movement of the foot), when it is hard to “straighten” the ankle. Vice-versa, in the negative kick the ankle must go back to a less straight angle. This is much easier, as the articulation can move more easily back towards the relaxed 90°. So the 33° angle evidently gives much more comfort to the diver in the positive kick. This is so a good solution when the diver needs to fin long distances and for long periods of times. In general, the blade will also feel softer on the leg, and so the fatigue is much reduced with the 33° angle.

Minuses
As it often happens, each solution can give advantages, but can also have some downsides. In particular, the 33° angle blade is a “slower” blade. This means it is less reactive with the same effort and position of the foot of the diver. In fact, the position of the blade in the 33° solution has a delay in the positive kick. This determines of course less power return in every kick. In addition, with time a small loss of reactivity of the blade can be verified. This is valid for all blades, for each material and for every brand, even though with different intensities. In such situation, evidently the 20° blade has somehow a better resistance to this phenomena.

It is also true that the 33° angle blade requires a wider kick to achieve the same amount of thrust. Such aspect does not really effect the comfort or tire the diver, but can impact speed performance. In fact, a wider kick generates a bigger frontal section of the diver, meaning a reduced water penetration.

20° angle
The 20° angle is the original concept, and works well for the highly trained divers. It actually represents the most of the requests for Leaderfins.

Pluses
The 20° angle blade needs more work by the ankle of the diver. Still it is also advanced in the positive kick compared to the 33°. So with the 20° angle solution the thrust is more immediate. A very experienced diver could feel more comfortable with this solution. The kick can also be narrower, so water penetration can improve.

Minuses
Such angle is decidedly low, lower than the traditional 22°. The smaller angle by Leaderfins requires the diver to keep his ankles “extremely straight” while finning. This position reduces comfort and also relaxation during the dive. Long transfers and many hours of diving could determine higher stress to the ankles and to the calves.