SS-26 G-4 Thrasher

Thrasher (Submarine No.26) was laid down by William Cramp Shipbuilding in July 1910, renamed G-4 in 1911 and commissioned January 1914. Simon Lake finally went bankrupt after failing to deliver completed boats on time and losing contracts to various ersatz buyers. His company was picked up by Italian naval constructor Laurenti. G-4 was designed by Laurenti, a well known former Italian submarine designer. She was the last American submarine completed with gasoline engines. She was completed almost 33 months behind schedule by which time she was obsolete.

G-4's machinery was too light and a stabilizer had to be fitted to correct her rolling. G-4 had a boat shaped pressure hull rather than circular-sectioned; this increased the amount of space available within the hull. There were two engines on each propeller shaft for increased power over the earlier G-boats and Laurenti used watertight bulkheads. Diving time was claimed to be improved on this version but there was a need to ventilate the engine compartment which actually increased the time needed to prepare to dive.

Test depth was 200 feet; G-4 could attain 14 knots on the surface and 9.5 knots submerged. Submerged endurance was three hours at 8 knots or 7.5 hours at 6 knots. Cruising range was 2,200 nm at 8 knots surfaced. There was one reload for each of the four torpedo tubes.

By 1916 standards, G-4 was considered by the submarine force to be a good boat. She served as schoolship at New London during World War One and test fired the Mk7 torpedo for the N and O-class boats after the war. She was decommissioned in September 1919 and scrapped.