Design and tests of a trawl-resistant package for ADCP´s

A package designed to protect an RDI acoustic Doppler current profiler (ADCP) for deployment in fishing areas is described. The package was tested and survived several passages of a trawl. The package has the shape of a truncated pyramid with a base 4 m by 3.3 m and a height of 53 cm. The housing, its deployment method, and some field test results are described. Some acoustic measurements were made to ascertain the effect of the housing on the beam pattern. The results show that this design can protect the instrument from bottom trawls and the acoustic beams are minimally affected by the plastic plate in front of the instrument