okay, the fish has a max depth, but the array onboard has a different depth for the scanforom the sidescan, as well as the mag or sub-bottom profiler.
the fish can auto fly above the bottom surface to maintain the proper overlap of the sidescan..
to be clear, the ss sensors are on either side of the fish and radiate downward.
the fish is programmed to be at the optimum depth above floor to cover th floor.
if the fish gets above the optimum depth, the area covered below the fish gets overlap and redundant, conversely, below, there will be gaps.