Pegasus Ratings On Submarine Exercise

Press, Volume XCVI, Issue 28447, 29 November 1957, Page 25

Pegasus Ratings On Submarine Exercise

The anti-submarine exercises in which H.M.S. Cardigan Bay is now taking part in New Zealand waters will be among the last for her crew before the men are flown back to the United Kingdom at the end of April. A complete new crew—ll officers and 150 ratings, the ship’s complement—will be flown out from England to man the ship. She has not left the Far Eastern station since she arrived in May, 1949. This is in accordance with the Royal Navy’s practice of transferring crews by aircraft rather than sending ships home on long, expensive voyages. Seventeen naval reservists from H.M.N.Z.S. Pegasus, Christchurch, six of them in their final year of compulsory training, spent last week in the Cardigan Bay and were able to appreciate at first hand the effectiveness, and the difficulties of anti-submarine warfare.

All T.A.S. (torpedo and antisubmarine) ratings, the class from Pegasus had had previous experience of asdic procedure, but only through “dummy runs” on the training equipment at their reserve base. There, under the instruction of Lieutenant-Com-mander P. O’Connor, first lieutenant and T.A.S. officer at Pegasus, and Petty Officer C. Beale, a regular navy T.A.S. instructor, they had learnt the procedure of holding echoes from submarines and calculating their range, bearing, speed and direction.

In the Cardigan Bay, however, they had a real submarine (H.M.S. Aurochs and on one day U.S.S. Bream) to work with and it was a real sound-wave search of the waters around the ship. The ships engaged in the exercise, conducted in the Hauraki Gulf, were two frigates, H.M.S. Cardigan Bay and H.M.N.Z.S. Kaniere, and a minesweeper, H.M.N.Z.S. Stawell. An A-class submarine, H.M.S. Aurochs, of the 4th Submarine Squadron, based with the Royal Australian Navy, was the prey and Sunderland flying-boats based at Hobsonville also took part in the exercise. Aircraft’s Part The aircraft’s task rested entirely on communications. Their pilots flew over the exercise area n attempts to spot the submarine’s periscope and also dropped sonobuoys as listening posts. The sonobuoys are microphones hung in the water from small transmitters which send back to the aircraft noises, chiefly propeller noises from the submarine. By listening to three sonobuoys in the water a fix can be obtained of the submarine’s position. The ratings from Pegasus received a week of instruction and T.A.S. practice in Cardigan Bay much superior to any the older members of the class had ever had on ships of the Royal New Zealand Navy. The week was planned so that each rating spent as much time as possible actually working on the asdic sets. With experience of other weeks at sea when most of their time had been spent chipping paint, scrubbing decks and repairing sea-boats, they appreciated this approach to what was intended as a week of instruction in the branch to which they had been drafted. Attacks on the submarine were conducted on a rotor system. Each rating took a turn at each of the sets used in tracking the submarine, a turn on port and starboard lookout—where they watched for the wake from a periscope and for smoke signals to indicate the submarine’s whereabouts—and a turn at the wheel, carrying out orders from the bridge to weave according to evasive patterns. They heard the echoes bouncing off, the hull of the submarine; they heard the high-pitched whistle of a porpoise and they were told the effect of different weather conditions on the success of their attacks. The most frustrating weather condition for an asdic operator is a variation in the temperature of the water in which the ship is moving. As light is refracted at an angle when it passes through substances of different densities, so the sound waves sent out beneath a ship are bent when they pass from a layer of water at one temperature to a layer of water at another temperature. U.S. Submarine “Attacked”

This condition existed during the first days of the exercise and reduced the effective range of the asdic equipment to a mere few hundred yards. On the third day, however, a strong wind cleared the water and conditions were nearly perfect. It was on that day that the Guppi class American • submarine U.S.S. Bream consented to be attacked, without any signal success for the Empire. Six of the Christchurch ratings saw the exercise not only through the binoculars on the bridge of Cardigan Bay, but through the periscope of H.M.S. Aurochs. They were taken out to the submarine in a whaler one afternoon and spent three hours at depths

ranging from 56ft to 100 ft while the surface vessels chased above them. Through the periscope they watched the Sunderlands passing overhead and the frigates approaching from 10 miles away. From that vantage point they were able to see the evasive tactics that a submarine skipper—in this case Commander H. Kempster—could employ against their asdic procedure.

Commanded by Captain G. D. Roberts, H.M.S. Cardigan Bay of the 3rd Frigate Squadron, is based at Singapore and Hong Kong. She is on loan to the Royal New Zealand Navy for three months and will visit Lyttelton during a tour of the South Island ports early next year before returning to Hong Kong.