S-class boats as blockade submarines

S-class boats carried six tubes and twelve reloads, a useful balance in a theatre where patrol areas and targets were closer than in the Pacific. Their smaller scale and underwater endurance suited a sea where an attacking boat had some chance of regaining contact. A second attack remained uncertain, but reloads had more operational value here than during a distant fleet-ambush patrol. British planners therefore regarded the class as an instrument of Mediterranean blockade against Italian shipping and naval movement.