Hydrophone unit

A hydrophone unit comprising a resilient central wire; a conductive wire coiled around the resilient central wire, said conductive wire being coated with a piezo material for generating an electrical signal in response to the presence of an acoustic vibration, wherein the resilient central wire is fabricated from spring steel, the conductive wire is a copper wire, the piezo material includes polyvinylidene difluoride; a layer of conductive material deposited on the piezo material-coated conductive wire, wherein the layer of conductive material comprises a silver ink; and a jacket of polyurethane.