A combination air deceleration and mooring module for A-sized buoys

Abstract

The A-sized standard is adopted for many buoys used in ocean monitoring that are deployed from aircraft, helicopters, ships and submarines using pressure and gravity launch tubes, as well as charge-activated devices (CAD). Unfortunately, most existing A-sized systems are drifting buoys and acquiring relatively long term measurements from a fixed location in littoral waters is difficult because currents tend to move these drifting buoys on shore or out of the region of active interest. A novel air brake and mooring module is presented in this paper that provides a reliable air deployment and autonomous mooring capability for A-sized systems. The module consists of a combined air brake/anchor and an autonomous scope adjusting mooring line spool. In air, the combined air brake/anchor is rigidly attached to the sensor package to eliminate parachute entanglement. In water, the air brake/anchor is released and moors the system in bottom types ranging from mud and sand to broken rock. The mooring module supports different mooring lines, including embedded conductors, and self-locks the mooring line at preprogrammed scopes in depths ranging between 20 and 200 m. The electronic components are low power and potted to eliminate leaks. A structural finite element model is used to design the high strength lightweight anchor and the size of the mooring module and buoy are minimized using a finite element numerical simulation. The final package is small, consuming 1/3 of the available space, and its volume is equivalent to the combined space utilized by existing parachutes and sensor suspension and communication lines.