The hydrographic survey department of Geo Plus has performed side scan sonar operations in 2010 for the Eemsgeul Salvage, a project commissioned by Van den Herik. Preparations for improving the access of the Eemshaven, where carried out.

In the vicinity of the German island Borkum, the first wreck was detected. The quality of the side scan sonar images was excellent. Geo Plus is experienced using various mulitbeam echo sounder systems. The side scan sonar (Elics 100/400 kHz version, vendor Ixblue) is a great addition to our equipment facility.

On board a survey vessel the sonar fish can be towed or mounted on a bracket (in very shallow water). It produces digital images of the sea floor, which in turn are being used for geological investigations and the search for objects like wrecks, mines and pipelines. This instrument transmits a sonar signal pulsing perpendicular to the sonar fish heading (so it is 'looking' sideways and downwards).

The sonar signal is concentrated in a narrow band on both sides (port and starboard) of the sonar fish. The returning echoes from one pulse are displayed as one single line, with dark and light portions of that line representing strong or weak echoes relative to the travel time. Relatively high frequencies (100 to 500 kHz) are suitable for detecting features smaller than 10 cm.


Photo: An image of the wreck near the German island of Borkum. It is a wooden ship which ribs are visible.