Abstract: A method using a tow body and sensor array for locating an underwater location beacon is provided. The steps of the method are moving the body and array in a direction of motion; orientating the array orthogonal to the direction of motion; beamforming acoustic conical beams from the array onto a seafloor; detecting a time series of acoustic data channels from the beacon; converting the data channels into spatial beams of acoustic frequency; determining if a signal of the underwater location beacon is present from each spatial beam; calculating likelihood functions for locations of the beacon to represent an area of the seafloor from which the signal of the underwater location beacon is to have originated; accumulating likelihood functions for the location of the underwater location beacon over the course of a search pattern; and producing a grid for a beacon location based on the likelihood functions.

Abstract: A separable fastener includes a fastener body having a head end and a shank nd. The head end defines a generally cylindrical open ended cavity in which a cylindrical punch is disposed. The cavity is sealed and closed by a gas generator that develops an increasing fluid pressure against the punch. The punch is restrained within the cavity by a retaining ring which yields once a preselected gas pressure is reached. The release of the punch causes it to rapidly accelerate in a short distance to impact the shank end of the fastener body. The shank end is thereby sheared from the body with the void created in the body being sealed by the impacting punch.