| || Preliminary experiments on the determination of the acoustic signature of ships
Author : Rao, V.N. ;Achyuthan, K. ;Narayanan, M.S.
Source : Defence Science Journal ; Vol:6(2) ; 1956 ; pp 117-128
Subject : 623.8 Naval Science
Keywords : Experiments ;Mangeto-striction tranducer
Abstract : A method has been developed at the Naval Physical Laboratory, Cochin for recording and analysing the acoustic signature of a ship. The equipment consists of a magneto-striction transducer, a panoramic spectrum analyser, a frequency analyser and other accessories carried on board Ins Cauvery, kept anchored 15 miles due west of Cochin. The hydrophone is lowered to a depth of 40 feet and kept at a distance of 200 feet from this ship. The Ship, INS Ranjit whose acoustic signature is being studied passes as close to the hydrophone as possible. The spectrum of noise, as recorded on the "panoramic" analysis is photographed for various positions of the ship. These observation are repeated several times and for different speeds of the ship. This experiment is later repeated with the functions of the two ships reversed so that the acoustic output of Cauvery also is obtained in a similar manner.