to adopt the new technique of prefabricating the hull in sections in the shops and assembling large units at the building berth.
To this modified group of submarines was fitted, at the extreme stern, an additional external torpedo tube, whilst the two tubes amidships were repositioned aft of the conning tower, angled to fire astern. These changes altered the shape and silhouette of the class, as did the removal of the bulbous bow casing. This had created a notable bow wave which, when running at periscope depth, hampered visibility and the correct trim of the boat. As a result of these alterations, the second group of boats were more streamlined, and the openings for the two external tubes were more clearly visible.
In addition to their 21-inch torpedo tubes. Group 2 T Class
