Plunger, Adder, Moccasin, Porpoise, and Shark at New Suffolk, New York circa 1903.
A 1912 view of the breech of the sole torpedo tube of USS Moccasin / A-4. Two torpedoes are on wooden skids in the foreground. The skids slid across the deck for loading.
The Plunger class was an early class of United StatesNavysubmarines, used primarily as training and experimental vessels for the newly formed "silent service" to familiarize naval personnel with the performance and operations of such craft. They were known as the "A class" after being renamed to A-type designations (A-1 through A-7) on 17 November 1911. All except Plunger ended up being stationed in the Philippines, an American possession, prior to the outbreak of World War I. They were shipped there on colliers (coal-carrying ships). In some instances, this class of submarines is referred to as the Adder class, as USS Adder was the first boat of the class to be completed.
The Plunger-class submarines were built at the beginning of the twentieth century largely as experimental vessels. The prototype, named Fulton, was later sold to Russia, and renamed Som. The Plunger class was built at two different locations on both coasts of the United States.
The five East Coast boats were based at New Suffolk, New York from 1903 until 1905, allowing New Suffolk to claim itself as the first submarine base in the United States. The squadron moved from New Suffolk to Newport, Rhode Island in 1905 where they were used to test torpedoes and develop submarine tactics.
In 1908 the A-2, A-4, A-6 and A-7 were moved on ships to Subic Bay in the Philippine Islands, where they served through the First World War. They were joined in 1915 by A-3 and A-5.
The class was given alphanumeric hull classification symbols (SS-2, SS-3, etc.) on 17 July 1920, after all but Grampus (SS-4) and Pike (SS-6) had been decommissioned. All of the Plunger-class boats were decommissioned by 1921, and all except Plunger used as targets. They were stricken from the Naval Vessel Register on 16 January 1922 and sold for scrap.