SAFETY GIRDLES

New Zealand Herald, Volume LXXVII, Issue 23619, 1 April 1940, Page 13

SAFETY GIRDLES

COUNTERING MINES NEW DEVICE FOR SHIPS BRITAIN'S REPLY TO HITLER [from OUR OWN correspondent] LONDON, March 12 * Hitler's secret weapon, the magnetic mine, is no longer secret, and it is likely that British" counter-measures may render it harmless. By de-magnet-ising or de-polarising, it is possible for ships to pass over magnetic mines without causing them to explode. The process is known as "de-gauss-ing," a gauss being a unit of magnetic flux. The term is derived from the name of a Scandinavian scientist who did much important research work in magnetism. The new process is effected by moans of a "snake" of wire running right round the hull of a ship at the level of the upper deck, with an electric current passing through it. When the Queen Elizabeth arrived at New York she was Wearing one of these nonmagnetic girdles. Ultimately every British ship, both naval and mercantile, will he so fitted. Secret of Equipment How the circuit is energised is a secret, but its effect is to de-magnetise the field through which the ship is passing. Already some hundreds of vessels have been equipped, and not one has been mined. It is understood that this simple method of defence against a new weapon was evolved in the experimental department of H.M.S. Vernon, the torpedo and mining school at Portsmouth, as the result of the researches of several scientists. Successful results were achieved in tho space of two or three months, a remarkable feat in view of the highly technical nature of the problem. The men who worked on the device are quito prepared to take a ship so fitted over a magnetic minefield. Not Expensive to Use One of the advantages of tho device is that it can be fitted to a ship of any size, from a yacht or trawler to a battleship, or, biggest of all, the Queen Elizabeth. It is not unduly expensive in relation to a ship's equipment; in fact, considering the immunity it con- : fers, it may be reckoned as extremely cheap. It took a fortnight to equip tho Queen Elizabeth, in view of her size and the fact that when fitted to her the apparatus had only just been developed, but the normal period is now about four days.