Fundamentally, the fin is an extension of the lower limb, increasing propulsion capacity and acting as if it were an integral part of the diver.
CONSTRUCTION AND MATERIALS
After the first propulsion flaps, created by Corlieu in 1920, many models were launched on the market. The fins have been the target of great evolution and a growing specialization for different activities or sports modalities, such as swimming with fins, diving in apnea, underwater hockey and scuba diving.
The fins consist essentially of two parts:
- The foot, which can have heel closed or open, is usually molded into different types of material, so as to be smooth and malleable but without losing structural stiffness.
- The blade, can be simple or have intermediate ribs, openings, channels or other devices that give it stability, flexibility and rigidity.
The basic features that a fin should have are as follows:
- The blade plane should extend the leg shaft and not the foot shaft.
- It must have sufficiently firm ribs to give the necessary stiffness to the assembly and channel the water flows.
The flaps can be made in various materials (rubber, plastic, fibreglass, carbon fibre, etc., often used together) and vary in their dimensions and stiffness. The bigger and harder they are, the more water they move, making propulsion faster but more physically demanding.
From these general principles, there is a huge range of models, whose characteristics and effectiveness result from different conceptions and details, each with its advantages for specific uses.
IN UNDERWATER DISPLACEMENT DURING DIVING THE FINS IS AN EQUIPMENT THAT ASSUMES AN IMPORTANT FUNCTION FOR THE BALANCE AND PROPULSION OF THE DIVER
TYPES OF FINS
- Fins with a closed heel or closed foot have the advantage of adapting better to the diver’s foot, forming a more fixed set and protecting it more effectively and the disadvantage of only being able to be used without the use of boots, usually with the use of thin neoprene socks.
- Fins without heel or open standing, are used with isothermal boots, thicker and with consistent rubber soles. They have a wider foot design, counting on the volume of the boot, which makes them more comfortable to put on and take off. The fact and being used with boots, allow the diver in the diving center, on the boat and walking routes to do not need another type of additional footwear.
The choice of fins depends not only on the experience gained but also on the physical skills of the diver. The hardness of the fins should not be excessive in order to meet the following requirements:
- Do not hurt your feet.
- Do not require excessive effort.
- Do not become painful during prolonged use.
- Be adapted to the type of activity practised.
The care with the maintenance of the fins is identical to the care to be taken with the mask and the tube, with the special recommendation to store them lying on a flat surface, to avoid deformation of the flap.