General characteristics and operational history of the Plunger-Class submarines in 20th century naval development

The A class submarine was developed in 1911 from the Plunger-class submarines, which played a significant role in the early development of the U.S. Navy’s quiet service. Their pre-war midget design, which was based in the Philippines, had an Electro Dynamic electric motor, an Otto petrol engine, and a 60-cell battery.

In the early days of the United States Navy, the Plunger class submarines were essential training and experimental ships for the emerging “silent service.” These submarines were crucial in introducing navy personnel to the distinct capabilities and methods of operation of such vessels in the early years of their deployment. It was on November 17, 1911, that they were renamed to A-type designations (A-1 through A-7) and became known as the “A class.”

Before the First World War broke out, all of the submarines of this class—apart from the Plunger—were finally based in the American-occupied Philippines. These submarines were a vital part of Manila’s harbour defence system, and they were transported on colliers or ships that carried coal. Due to the completion of the USS Adder, the first vessel in this class, this class of submarines is sometimes referred to as the Adder class in historical references. The Plunger class’s exclusive contribution to the formation of the U.S. Navy’s submarine fleet’s first capabilities highlights the class’s importance in the evolution of naval warfare during that era.

General Characteristics:

Plunger-class submarines are classified as midget submarines and have a displacement of 107 tonnes along with a small but practical design. The vessel is agile and adaptable, measuring 63 feet 10 inches in length, 11 feet 11 inches in beam, and 10 feet 7 inches in draft. The submarine’s single shaft is driven by a 60-cell battery in addition to a 160-horsepower Otto petrol engine and a 150 bhp Electro Dynamic electric motor.

When submerged, the Plunger-class submarine maintains an average speed of 7 knots (13 km/h; 8.1 mph) and reaches a top speed of 8 knots (15 km/h; 9.2 mph). It can demonstrate its underwater proficiency up to a test depth of 150 feet (46 metres). Its seven-person crew emphasises the submarine’s function as a small-sized but effective naval weapon.

Fitted with a single 18-inch (450 mm) torpedo tube, the Plunger-class submarine has a powerful armament when it comes to fighting. The offensive capabilities of the submarine are increased by this adaptable tube, which can carry three long or five short torpedoes. Plunger-class submarines combine manoeuvrability, firepower, and strategic value in a well-balanced package of features and armament that makes it a noteworthy example of midget submarine design.

Operational History:

The five boats (A-1 through A-5) that made up the Plunger-class submarines were first stationed at Holland Torpedo Boat Station in New Suffolk, New York, from 1903 to 1905. New Suffolk was able to establish itself as the country’s first submarine base during this time. The submarines were mostly used for torpedo testing and the development of submarine tactics after the squadron moved to Newport, Rhode Island, in 1905.

A major change came in 1908 when four submarines of the Plunger class—A-2, A-4, A-6, and A-7—were shipped to Subic Bay in the Philippine Islands. During the First World War, these submarines were involved in naval activities. A-3 and A-5 later joined their counterparts in Subic Bay in 1915. At the same time, A-1, also called Plunger, was stationed in Charleston, South Carolina, until her decommissioning in 1913.

Throughout their service lifetimes, the Plunger-class submarines proved to be dependable and efficient despite some early flaws. Their design drew a lot of interest from foreign navies, who saw them as innovators in submarine technology. The EB 7P design, which was slightly altered, was the basis for the first submarines built by the British Royal Navy, Japan, the Netherlands, and Imperial Russia. Nevertheless, these submarines were outdated before the end of World War I due to the quick advances in military technology during the early 1900s. 

The class was formally recognised as individual identities on July 17, 1920, when they were allocated alphanumeric hull classification symbols (SS-2, SS-3, etc.). Except for Grampus (SS-4) and Pike (SS-6), all Plunger-class submarines had been decommissioned at this point. By 1921, all of the class—including Plunger—had been deactivated and converted into targets. The Plunger-class submarines were officially withdrawn from the Naval Vessel Register on January 16, 1922, and were then sold for scrap. This marked the end of their active existence.