We are about to undertake a mid channel search something we don’t do that often. Normally we are looking very closely at the seabed on short ranges at high frequency to give us the best imagery for spotting half buried cannons etc, here we are looking at a quarter mile swath of seabed from left to right and we are honing our skills and working on a few tricks we have up our sleeve to deal with pitch and roll which often causes problems on the longer ranges with a slower ping rate. Very pleased with the C-Max sonar that really shouldn’t work as well as it does on full range here in only 13 metres of water, the tow fish is literally almost on the surface! When we start our search it will be forty five metres below the surface to give us optimum range for our search in sixty five metres of water. In this image you can see Portland harbour wall the Countess of Erne and the stone barge on the left as well as some smaller bits and pieces. This image is also a good example of how the sonar sees different seabed densities, in this case silt and gravel mixed with shells.