Underwater practice mine

摘要

1,024,143. Practice mines. A. CUPELLA. Feb. 22, 1965 [Feb. 26, 1964], No. 7512/65. Heading B7A. An underwater practice mine comprises a device or devices sensitive to an ambient influence or influences (e.g. a pressure-sensing device, a magnetic-sensing device and an acoustic-sensing device) means for converting the output of the said device(s) into electrical signal(s), and a magnetic tape recorder for recording said signal(s).