A shark proof cage is an extremely strong metal cage used by a SCUBA diver to safely examine dangerous types of sharks up close, such as the Great White shark or bull shark. Shark proof cages are built to withstand being rammed by large, powerful sharks. The cages provide a visual and tactile deterrent to sharks. Cage diving allows people to come very close to sharks and is mainly used for Great White sharks.
On September 4, 1979, US patent number 4166462 was issued for a self-propelled shark proof cage [1]; the cage was designed to allow abalone divers to collect abalone without becoming vulnerable to attack. [2]Thanks to the propulsion system, the abalone divers would exert themselves less and therefore be able to collect their prey for longer periods of time.[3] 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 objects are attached to the frame so that the cage may be made approximately the same density as saltwater. [4] This patent expired on September 4, 1996.[5]
In 2007, due to poor shark wrangling a commercial shark cage was destroyed off the coast of Guadalupe Island after a 15-foot Great White shark became entangled in it and tore the cage apart in a frantic effort to free itself. [6] [7]Tourists captured video of the incident[8], which quickly spread throughout the Internet.