If you’ve visited the Submarine Force Museum, you probably noticed the model wall that runs the length of our main hallway. It displays scale models of each class of American submarine from 1900 to the present, along with a list of all the boats’ names and hull numbers. Many visitors notice that there are large gaps in the hull numbers in certain spots and want to know why.
In general, it comes down to changes in priorities. Most of the subs that the Navy has canceled were added to the construction schedule during World War II, when shipyards were churning out dozens of boats each year. When the war ended, so did the demand for new construction. That’s why the canceled hull numbers tend to be in the 400s and 500s (to be exact: 427-434, 438-474, 495-521, 530-549, 557-562)—as the United States’ needs evolved throughout the 1940s and 1950s, when the 400s and 500s were being built, some subs were deemed necessary while others went by the wayside. To avoid confusion in the future, canceled hull numbers were simply discarded.
On 12 August 1945, the U.S. Navy canceled the construction of six submarines: PCU TURBOT (SS-427), PCU ULUA (SS-428), PCU POMPANO (SS-491), PCU GRAYLING (SS-492), PCU NEEDLEFISH (SS-493), and PCU SCULPIN (SS-494).
TURBOT, whose keel had been laid at the Cramp Shipbuilding Company in Philadelphia, PA, back on 13 November 1943, was launched, only partially completed, on 12 April 1946. Instead of scrapping her, the Navy assigned the boat to the Naval Ship Research and Development Center in Annapolis, MD, where she was used for research into the reduction of machinery noise within submarine hulls. Although she was sold for scrap in 1958, TURBOT remained at the pier at the North Severn Naval Station in Maryland, providing a platform for testing into the 1980s. She contributed some of her parts to other submarines including USS PAMPANITO (SS-383), which received her six torpedo air flasks.
Coincidentally, ULUA’s keel had been laid down on precisely the same date and at the same shipbuilding company as TURBOT. Her incomplete hull was launched eleven days after TURBOT’s and then towed north, to Portsmouth Naval Shipyard in Kittery, ME. She, too, would serve as a test platform, becoming a site for research into new weapons and submarine design. On 30 September 1958, she was sold for scrap.
POMPANO’s keel was laid down on 16 July 1945 at Portsmouth Navy Yard, but the contract was canceled less than a month later.
GRAYLING was assigned her name on 29 August 1944, but her keel was never laid down.
NEEDLEFISH was authorized on 26 January 1945, but her keel was never laid down.
SCULPIN was authorized, but her keel was never laid down.