COMPACT UNDERWATER BUOYANCY SYSTEM FOR EXPENDABLE SONOBUOYS

THERE IS NEED FOR A COMPACT UNDERWATER BUOYANCY SYSTEM CAPABLE OF MAINTAINING A SPECIFIED (ABOUT 10 LB) WEIGHT AT ANY PRESET WATER DEPTH FROM 0 TO 2,000 FT. IT WOULD BE USED IN EXPENDABLE SONOBUOYS WHERE HYDROPHONES OR TRANSDUCERS MUST BE KEPT AT A PRESET DEPTH. DEFENSE SYSTEMS INC. (DSI) PROPOSES TO BUILD AND DEMONSTRATE IN PHASE I SUCH A DEVICE IN THE FORM OF AN EXPANDING, NESTED SET OF 6" DIAMETER 4" LONG CYLINDERS. UPON DEPLOYMENT AND ACTIVATION BY A SALT WATER SWITCH AND ELECTRONIC TIMER, AN INITIAL EXPANSION OF THE NESTED CYLINDERS TAKES PLACE TO COMPENSATE FOR THE PAYLOAD WEIGHT. FROM THEN ON A MICROPROCESSOR AND PRESSURE-SENSOR-CONTROLLED STEPPING MOTOR IS USED TO MICRO ADJUST CYLINDER EXPANSION TO CAUSE THE DEVICE TO CHANGE BUOYANCY, THUS MAINTAINING DEPTH AT THE PRESET LEVEL. THE BUOYANCY DEVICE USES LITTLE ELECTRIC POWER, CONTAINS NO HAZARDOUS DEVICES AND HAS A VERY LOW PROJECTED UNIT COST. IT IS FOR THIS REASON THAT DSI OFFERS A COMPLETELY FUNCTIONAL UNIT AS A PHASE I DELIVERABLE. IN PHASE II PRODUCTION PROTOTYPES AND UNITS FOR NAVY TESTING AND INITIAL DEPLOYMENT ARE OFFERED.