Fleet Submarines of World War 2: The Floating Drydock

The GATO class, like the later BALAO and TENCH class, were developed from improved versions of the early "T" (SSI98-211) class. Orders were plac­ed in 1940 for the FY 1941 shipbuilding program. The design of this subma­rine was frozen so the shipyards could mass produce these boats. The Electric Boat Company of Groton (New London), CT, received the first order for SS212-214. Portsmouth Naval Shipyard in New Hampshire was about to re­ceive an order for three boats (SS218-217), when the Navy went into a major Fleet expansion program. This expansion called for 22 more boats to be built, and Mare Island Naval Shipyard received four of these boats. Eight went to Portsmouth and the balance to EB. Before the ink dried on the contracts, forty-three more boats were ordered. The 1941-42 building called for two more boats (SS283-284) of the GATO design. These two boats went to Mare Island. A fourth yard, Manitowoc, WI, received orders to build SS265-274. The first submarine to be completed and commissioned was the USS DRUM SS228 built by Portsmouth.
As designed, the early boats had their periscope housing enclosed with a high sail area and bridge. During the war to reduce the silhouette, the super­structure was cut down in stages. As new boats were being built, the latest changes were made to them while building. Although the boats built at EB and Portsmouth were of the same class, external changes can be seen. The most conspicuous was the design of the holes cut into the side of the superstructure to flood and drain it during surfacing and diving...