Shark cage

A shark-proof cage is a metal cage used by an underwater diver to observe dangerous types of sharks up close in relative safety. This can include various species of shark, but the most commonly observed within the confines of a cage are the great white shark and the bull shark, which are both known to be aggressive at times. Shark-proof cages are built to withstand being rammed and bitten by sharks, and be able to protect the user from attacks. Cages can provide a visual and tactile deterrent to sharks. Cage-diving allows people to closely monitor sharks, and sometimes interact with them.

The shark-proof cage is also used in the controversial exercise of shark baiting, where tourists are lowered in a cage while the tour guides bait the waters for sharks.

On September 4, 1979, US patent number 4166462 was issued for a self-propelled shark-proof cage; being designed to allow abalone divers to collect abalone without becoming vulnerable to attack. Thanks to the propulsion system, abalone divers would exert themselves less and, therefore, be able to collect their prey for longer periods of time. The patent abstract details a self-propelled cage with at least one access opening and a propeller mounting frame that carries both an air motor and a propeller. Buoyant material is attached to the frame so that the cage may be made neutrally buoyant in saltwater. This patent expired on September 4, 1996.

In 2005, a British tourist, Mark Currie, was exposed to a high risk of injury or death when a 5-metre (18 ft) great white shark bit through the bars of a shark cage being used during a recreational shark dive off the coast of South Africa. The shark circled the boat several times, and began to attack the side of the cage, then started to crush and bite through. The captain of the boat was trying to distract the shark by hitting it on the head with an iron pole, but the shark bit into one of the buoys at the top of the cage, which made the cage start to sink. Currie realized that he could either get eaten or drown because he had only a mask, not any breathing apparatus. Currie quickly swam out of the top of the cage and was pulled to safety by the boat's captain, who fended off the shark with blows to its head.

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