monitor transducer
Inventory Number: 1997-1-0832
Classification: Transducer
underwater acoustics,
Maker: Underwater Sound Laboratory, Harvard University (1941 - 1949)
Cultural Region:
13.4 × 7.3 × 7.3 cm (5 1/4 × 2 7/8 × 2 7/8 in.)
Applied Acoustics in Subsurface Warfare
A short cylindrical transducer is coated with an orange resin substance, painted over in grey. On top is a round metallic handle screwed down. Two cut wires can be seen. It appears to be a type S1 tranducer.
According to Hunt's report: "These [hydrophones for sound gear monitors] were of the radially expanding tubular type. In the advanced designs the winding was disposed around a wooden core bissected by a diametral septum of permanent-magnet material which provided proper polarization for the oxide-annealed nickel tube. These were constructed in various lengths and diameters for different uses and for different frequency ranges. Several thousand hydrophone units based on these designs were eventually put under Navy procurement."