Naval technology used in shark repellent system


That military – and in this instance naval – technology can be successfully adapted to civilian use has again been demonstrated, this time by Armscor’s Institute for Maritime Technology (IMT).

Simon’s Town-based IMT collaborated with the KwaZulu-Natal Sharks Board (KZNSB) to develop a shark repellent cable system as a potential green alternative to shark nets and drum lines. These are currently in use at 37 of the province’s most popular swimming beaches.

The KZNSB, the only organisation of its kind in the world, has long been investigating the use of new technology to provide alternatives to nets and drum lines.

A major investment by the provincial Department of Economic Development, Tourism and Environmental Affairs enabled the KZNSB to undertake further research and development of this technology.

This saw IMT contracted to design and build a demonstrator cable six years ago. The specialist engineering and technical team at IMT first built a short cable to be tested for sea-worthiness. Medical evaluation showed the electronic pulse emitted was well within conservative safety limits and a full-length demonstrator cable was constructed.

The shark repellent cable emits a low frequency, low power electric field into the immediate area around it. This, Armscor said, has been proven to repel sharks. The cable system consists of an array of electric field generation units along a barrier line. The electrode produces an electric field when suspended in water. The electrodes are controlled by barrier units either anchored or floating on the surface. The system is powered by a base station and system health is monitored remotely.

The system has completed two successful sea evaluations, in False Bay at Glencairn Beach and Mossel Bay. Data collected during the sea evaluations supports a design solution to repel sharks.

An Armscor spokesman said the shark repellent cable system developed through the KZNSB/Armscor partnership leads the world in shark repellent technology.