A Buoy Supported Acoustical Data Acquisition System

A marine acoustical data gathering system is described which consists of a planar array of 26 hydrophones supported from the surface by a spar buoy. The completely analog system is hardwired from the array through a 1500-foot down cable to the buoy and through a 4500-foot multiconductor floatable cable from the buoy to a recording vessel. The hydrophones, four environmental sensors, and subsurface electronics pressure vessel are supported by the 50-foot-diameter aluminum tube structure which could be suspended to depths of near surface to 1500 feet. Amplifiers and attenuators for processing the data prior to recording are contained in the ship-board electronics. The system was designed to record ambient noise over a bandwidth of 10 Hz to 3.0 kHz at system noise levels equivalent to sea state zero. At the same time, it was designed to have the flexibility for accommodating large signals such as those from close proximity surface vessels. The circuitry is described, and the operational capabilities of the system are illustrated.