Shelby F. Sullivan

Large, air deployable, volumetric hydrophone array

An air deployable, volumetric hydrophone array uses three horizontal boomsadiating from a central hub suspended at the array operating depth. Loose lines of hydrophones are hung from pairs of points on the boom structure and hang in arcs approximating catenaries.

Transducer assembly for deep submergence

A transducer assembly comprising: a diaphragm; at least one transducer elnt bonded by its head to the diaphragm; a pressure-resistant means, for supporting the transducer assembly; an acoustic isolator mounted about the transducer element and located between the diaphragm and the pressure-resistant means; the material of the acoustic isolator being elastically linear and equal in thickness to one-quarter wavelength of the corresponding operating frequency of the transducer element.

Transducer Pressure‐Release Material for Deep Submergence Applications

A new acoustic pressure‐release material is proposed for use as a reflective backing in deep submergence transducer arrays. The material is high‐temperature aviation insulation manufactured by Johns‐Manville under the trade name Min‐K 2000, available in several densities between 20 lb/ft3 and 35 lb/ft3. As purchased, the material is inelastic and is prestressed for transducer applications by uniaxial compression to a pressure greater than the design depth of the array structure. The material takes a permanent set depending on the initial density, the resulting material having a density that depends on the inelastic prestress and not on the initial density of the parent material. Similarly, acoustic velocity for longitudinal waves is dependent only on the inelastic prestress. The pressed material is rigid and machinable, having about half the impedance of acoustic backing paper at the same operating depth. A test array fabricated with this material and containing an air‐filled cylinder at its center showed...