Image Number 3 for United States Patent #4208738.
A sonar array consists of a significant number of interconnected disk-shaped transducer projectors operating in the bending mode and packaged in a cylindrical housing including a first or lower section including an electronics and battery package for powering the transducer projectors; a main housing containing the stacked, interconnected transducer elements and having padding of foam material for protecting the transducer elements during deployment and handling; and a rear case section which contains a parachute to control rate and attitude of descent from the launching aircraft, a float or buoy in association with the parachute for providing flotation during operation, and a coiled length of nylon rope for suspending the deployed array at the desired distance below the surface. A retaining line or spring clips are used to hold the transducer elements in the main case section during descent in the water following separation of the rear case section and uncoiling of the nylon rope. When the housing reaches the end of the nylon rope, the resulting force acts to pull the transducer elements out of the main case section, breaking the retaining line and/or overcoming the force of the spring clips until the entire array is suspended in the ocean above the housing. A suitable time-responsive means operates to deflate the float or buoy when the array has completed its task.