The British submarine HMS Olympus, sank in 1942 at the height of the siege of Malta and is one of the most historic wrecks off the coast of this island.

The discovery of the wreck completes a historic and tragic story. During the height of the German and Italian blockade of Malta, the British Navy fought a constant battle to keep the valiant Island supplied with food, fuel and war supplies. Submarines were an essential part of this operation, both in bringing in supplies and defending the merchant shipping.

The minute scales, which are just 200 micrometres long, are made from tough enamel, such as that found on teeth, giving the skin a rough texture like sandpaper. Lying flat, they had previously been found to reduce drag as the shark swims. Some reports had also suggested that sharks can bristle their scales, causing them to stand up on end.

Experiments have now revealed that tiny vortices or whirlpools formed within the cavities between the scales.