DIMES Progress Report

RR0901 - 17 January 2009

We have deployed four of the sound source moorings and are roughly on schedule, despite some annoying weather and seas.

Bathymetry in the vicinity of the first sound source mooring deployed on the cruise. The data for this image come from a Simrad EM120 "Multibeam" system, which probes the bottom with a scanning acoustic beam with a horizontal resolution of about 100 meters across a swath more than 20 km wide perpendicular to the ship's track. The data for these pictures are being cleaned up and presented by Uriel Zajaczkovski and Magdalena Carranza, with guidance from Nicolas Wienders.

The position at which the mooring anchor was released is shown. The anchor is the last component to go over the stern, with a long cable (about 4500 meters), the sound source, and flotation (26 hollow glass spheres encased in plastic shells) streaming behind the ship in a straight line at the surface. When the anchor goes over, it pulls it all down. The anchor swings back about 1000 meters toward the glass balls, on the way down, while the glass balls are pulled along towards the anchor several kilometers. It all ends up with the anchor on the bottom, and the wire upright with the sound source and then the glass balls at the top.