If the thought of being approached by a Great White wasn't bad enough, it has been revealed the US Navy once tried to use sharks to deliver bombs into enemy waters.

The secret mission ran from 1958-1971 and was called Project Headgear.

It was uncovered by Mary Roach, who was researching sharks for her latest book Grunt: The Curious Science of Humans at War.

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The secret mission ran from 1958-1971 and was called Project Headgear - when it was abandoned following several tests with tethers an in swimming pools.

HOW IT WORKED Bombs would be strapped to the shark, which would also wear a box on its head which had a compass and could communicate with controllers. The sharks also had electrodes inserted into them connected to the box. The box was programmed to monitor the shark, and if it seemed to swim off course, it would send out an electric shock of between 5-25 volts to one of the shark's sides to get it to swim towards the desired target. Advertisement

Revealing the project for MIT'S Undark site, she wrote she first came across it while 'Reading a historical article on sharks in Marine Fisheries Review.'

'The author, José Castro, quoted a newspaper piece saying that the goal had been to 'convert the shark into a remote-controlled torpedo that could ram a ship while carrying a load of explosives.''

Although the discovery did not make it into her book, following its publication she met Michael Morisy, the founder of a website called MuckRock which specialises in helping people in the US file, track and share public records requests.

He helped her obtain the report into the project, which was carried out at three US labs - Lerner, which is now closed, Mote, and the Scripps Institution of Oceanography.

'The shark wasn't so much a 'torpedo' as a suicide bomber,' she wrote.

'The shark would simply carry the explosives close enough that the target would be destroyed when the bomb detonated.'

The report's co-authors Perry W Gilbert, shark expert and former director of Mote Marine Laboratory, and marine engineer James Marion Snodgrass said that sharks were preferred over dolphins as the latter were too smart and could not be trusted to follow orders.

Dolphins are used to hunt mines in other projects.

'Man can intellectually dominate a shark — something he finds much harder to do with a porpoise.' the report concluded.

'We have serious reservations concerning the suitability of a shark as a vehicle for command guidance or for transporting a payload any distance,' reads the conclusion of the Final Report, dated June 16, 1971.

The report says that tests were carried out with the sharks on tethers and four versions of the headgear were developed between 1958-1967.

However, later tests with the animals in swimming pools had disappointing results, and the project was abandoned.

'We have serious reservations concerning the suitability of a shark as a vehicle for command guidance or for transporting a payload any distance,' reads the conclusion of the Final Report, dated June 16, 1971.