GB130350A - Improvements in Electromagnetic Methods of Detecting Submarines. - Google Patents

Abstract

130,350. Beattie, R. Dec. 27, 1917. Signalling proximity of vessels.-The proximity of submarines, submerged wrecks, &c. is detected by means of two rapidly rotated coils, carried by a towed support and connected so that, when rotated in the undisturbed terrestrial magnetic field, no resultant current is produced, but when rotated in the disturbed field due to proximity of a submarine &c., an out-of-balance current is produced, which may be detected by a galvanometer or other means. The coils may be mounted on a common shaft, or on separate shafts in alinement, the coils rotating synchronously. Rotation may be imparted by movement of the towed body or by means of propellers and gearing; or the towed body and coils may rotate as a whole. Or rotation may be produced from the parent ship by rotation of the towing-cable, or by supply of electric, hydraulic, or pneumatic power to suitable motors in the towed body. The resultant current may be detected by an alternating-current instrument and may be transformed up, or amplified by valves, or may be rendered audible in a telephone instrument bv known means. Or the current may be rectified and direct-current detecting-means used. The coils may be connected up in series or opposition, and balance may be obtained by suitable means such as the use of adjustable resistances and inductances, bridge balance methods, or by auxiliary balancing- coils to which current may be adjustably supplied, the coils being fixed or rotating. Means may be provided for automatically maintaining a predetermined depth of submersion of the towed body, and for indicating the depth on the parent ship. Examples are given of the various methods of constructing and connecting up the coils. Fig. 1 shows the simple form with the rotating coils M<1>, M<2> on a common shaft, in opposition, and connected through slip-rings S', S<2> with the galvanometer or other detecting-instrument G. Auxiliary balancing-coils to which current is supplied are shown at C<1>, C<2>. Fig. 11 shows the means for maintaining the towed body at pre. determined depth by the use of horizontal rudders H on a shaft A which is moved by an arm B engaged by a nut provided with two ratchet-wheels R<1>, R<2>, and screwing up and down on a fixed screwed spindle C. The ratchet-wheels are operated by one of two pawls on a forked member F which is reciprocated by an arm E and rod D operated by suitable gearing from the rotating shaft. The member F has a pivotal connexion with the arm E, and the pawls are clear of the ratchet-wheels, or one or other of the pawls engages its ratchet-wheel, according to the lateral position of the member F as determined by an adjustable spring O and the pressure of the water acting on a piston P. A safety device operating when the rudders reach extreme positions comprises a lever N<1> connected by a link N<2> with the member F and operated by a disk U with a camgroove mounted on the shaft A.