Patent GB-191517399-A (GB)
Title: Improvements in Marine Depth Sounding.
Inventor: PAGET RICHARD ARTHUR SURTEES
IPC: G01S11/14
Filed: 1915-12-11
Abstract: 17,399. Paget, Sir R. A. S., and Duddell, W. Dec. 11. Audible signals; recording signals; subaqueous sound signals.-In a marine sounding system, the interval between the release of a small bomb, designed to fall through water at a known speed, and the report at the ship of its explosion upon reaching the bottom is a measure of the depth. Fig. 1 shows a bomb adapted to take an ordinary 4-bore sporting- cartridge 1 within a heavy lead casting 4 of stream-line form, above which are four straight steadying-vanes 3 with an annular ring 5 furnishing an additional resistance. The percussion firing-mechanism is of the spring-striker kind in which a heavy head 11 hangs from a base cap 10 by means of a spring 12. At safety, the head is suspended by a cross-pin 13, taking into the upper ends of slots 18 in the tubular top of the head and carried by a central rod 14 which is released at a predetermined depth by rotation of a locking-propeller 15, whereupon a spring 17 carries the pin to the lower end of the slot, leaving the head hanging freely from its spring 12. Upon abrupt stoppage, the head is urged downwards by inertia, rocking a trigger 20 by the aid of a conical collar 7 and thus releasing a spring striker 21. Alternatively, for electric firing, the heavy head may contain a small battery and the striking-pin may complete circuit for an electric fuze in the cartridge. If the vanes are helical, rotation of the bomb during descent will ensue and may be utilized by means of a centrifugal governor to maintain an electric contact pin sufficiently raised to prevent firing, even when the safety rod is released by the locking-propeller, until movement ceases. Automatic timeinterval measurements are secured by the apparatus shown in Fig. 4, wherein the passage of the bomb from the launching - shoot 38 closes a contact 40 so that suitable connexions may actuate a recording-pen 32, the sound wave of the explosion being recorded by means of a mass 44, Fig. 5, suspended by a pair of stretched steel wires 43, and forced against a second contact device by the shock to the ship's hull In this way, a second recording-pen 31 may be actuated, the starting of the record surface being effected upon the closing of contacts 39 in the circuit of an electro-magnet 37 when the shoot is swung into the position shown, and time graduations being applied by a clock-controlled pen (not shown). The vibratory mass 44 consists of two parts clamping between them the wires, which are subject to adjustment for sensitiveness and pitch by means of a screw. bolt 47 carrying a pulley 45 around which they pass, the bolt being positioned and locked by the nuts 48, 49. Contact is made by a silver spring 50 upon the vibratory mass with a platinum point 51 upon a screw provided with spring-controlled coarse and fine adjustments. Alternatively, the contact may be normally closed, or it may even be dispensed with, if a microphone and transformer are connected to the pen-operating magnet. Modifications mentioned include the combination of percussion and centrifugal striking-mechanisms, firing by water-pressure diminution upon stoppage, hand starting and stopping of the recording-mechanism, mechanical release of the bomb, direct graduation of the recording -apparatus for depth to avoid reference to tables, release of the bomb from a height above water adapted to give the terminal velocity upon immersion, and correction for ship's movement during the upward travel of the sound.