The insignia of the U.S. Submarine Service is a submarine flanked by two dolphin fish.
The origin of the U.S Submarine Service insignia dates back to 1912. On June 13 of that year, Captain Ernest J. King, Commander Submarine Division Three, later a Fleet Admiral and Chief of Naval Operations during World War I, suggested that a distinguishing device for qualified submariners be adopted.
The original design was based on Captain King's own pen and ink sketches. Submarine qualification pins were first authorized for use in 1941, the officers wearing gold dolphins on the left breast while enlisted members wore silver dolphins embroidered on the right sleeve.
Today both officer and enlisted insignia are worn on the left breast. To "Qualify Submarines," a submariner must possess an in depth knowledge of ship's construction, operation, damage control and demonstrate reliability under battle condition.
Dolphins, the traditional attendants to Poseidon - patron deity to Sailors, are symbolic of calm seas and are sometimes call the "Sailor's friend".
