Understanding depth sounder readings
I have a Garmin 550S depth sounder. Like other sounders on the market, it gives a pictorial representation of whats on the sea bed, and in the water between the sea bed and the transponder.
As well as being able to visualise the shape of the sea bed, drop-offs etc, it shows a red band which appears to vary in thickness, presumably depending upon what the sea bed is made up of, such as sand, rock or clay??
I've looked through the owners manual, but unless I'm missing something, there isn't much to explain what it is you're looking at. What do the various colours mean?
Can anyone give some hints/ tips on how to interpret the on-screen image?