As fast as sharks

2004/09/05 Galarraga Aiestaran, Ana - Elhuyar Zientzia

• Materialak
• Fisika

The appearance of shark bark has also been given to sailboat helmets to circulate faster.

Year 2000, Sydney Olympics. At the last moment the International Olympic Committee has decided that yes, that swimmers can wear shark fur swimsuits. Australian swimmers should immediately decide whether to swim in old swimsuits or wear new ones. It seems that with the news they can win a few seconds. And the fastest swimmer of those Games bet on the new ones. He looked like a real shark.

At this year's Olympic Games some swimmers have been unable to choose. Michael Phelps, Inge De Bruijn, Grant Hackett, Amanda Beard and many others were forced to wear Fatskin swimsuits. In fact, Fatskin baptized the swimsuit that Speedo made from the bark of sharks.

Speedo is the sponsor of these swimmers, like Michael Phelps, who, if he tied the Mark Spitz brand, promised that Speedo would donate him a million dollars. Finally, Phelps has not reached Spitz level, so Speedo has not had to pull that million out of his pocket. However, surely you would have liked to lose that money, because it would have won much more with the publicity achieved thanks to the champion.

This is what some scientists accuse Speedo that everything is marketing. According to them, Speedo's research is not entirely correct and science is just an excuse to increase sales.

The shark as an example

The shark partly owes its speed to its skin.

However, Speedo has done numerous research to design the most suitable material for the swimsuit, focusing on sharks recently. However, neither the only nor the first take as a model the sharks.

The skin of the shark is not soft, it has small wrinkles that reduce the surface affected by water. In addition, at the end these wrinkles are larger than at the bottom, so the turbulence is less.

The hull of the sailboat that won the 1987 Copa de América had a special texture. They did this by imitating the texture of the shark's skin. However, his advantage over others has led him to ban his use.

Arguments of Speedo

No wonder, therefore, that Speedo also considers sharks. Fastskin has made the swimsuit based on the shark. This bathtub represents a reduction in passive resistance of 4% in men and 3% in women. This is because variations and breasts increase resistance, and therefore the difference between both sexes is greater.

From the hand of Inge De Bruijn and Grant Hackett Speedo, shaped like a real shark.

Swimsuits are designed to reduce two types of resistance, skin friction and pressure resistance. To reduce skin friction, the key is to perform wrinkles with the right size. If they are more or less large than necessary, the water fills ‘valleys’, so the resulting surface is greater than that of a conventional swimsuit.

On the other hand, there is pressure resistance. When water passes through the eyebrows, breasts, knees and other irregularly shaped parts, it is immediately removed from the skin causing an absorbent effect. To reduce this absorption, Fastskin is punched in several places like a golf ball. Thus, the swimsuit holds the water forming a layer of uninterrupted water throughout the body.

Through the computer the dynamics of fluids in the pool have been studied, both with mannequins and with swimmers. Mannequins send data from water to the computer, so they have known to what extent friction occurs in each place. Taking this information into account, the Fastskin swimsuit has used fabrics of two textures. After thousands of tests, the Speedo have no doubt that the swimsuit that mimics the skin of the shark helps to swim faster.

Scientific doubts

However, some scientists disagree. According to a study published last year in Sports Biomechanics magazine, the Fastskin swimsuit does not reduce resistance. The research was conducted by several swimmers, some with normal swimwear and others with shark skin shape. And they noticed no differences.

Also, skeptical scientists consider that the flow around a boat has nothing to do with a swimmer, and less with speed. The maximum speed that people can reach is about 7 km/h, which means about a quarter of a boat or shark. Therefore, a texture that helps the shark can have a reverse effect on the human being.

If we consider the statements of a last generation swimmer, it may be worth using this type of swimsuit. In his opinion, "the best of these garments is the psychological aspect. If the swimsuit makes swimming faster in theory, in the end one swims faster."

Published in 7K.