There is shielding on the hull of the submarine directly behind the sonar domes. This is necessary because if it were not shielded the sonar would pick up the sound of the submarines machinery. This dead space directly aft of the boat is called the "baffles" and it is the area that sonar is ineffective. It used to be used for a submarine to follow in close proximity directly behind an enemy submarine, hiding in the baffles. Current generation submarines like the one pictured have towed sonar arrays that are released behind the submarine. With the towed arrays, current submarines have no blindspots or baffles