The insignia of the US Navy's Submarine Service is a submarine flanked by two dolphins. Dolphins or porpoises, traditional attendants to Poseidon, Greek God of the Sea and patron deity of sailors, are symbolic of a clam sea and are sometimes called the "Sailors friend."
The origin of the US Navy's Submarine Service insignia dates back to 1912. On 13 June of that year, Captain Ernest J King, USN later to become Fleet Admiral and Chief of Naval Operations during World War II, and at that time Commander Submarine Division Three, suggested to the Secretary of the Navy, via the Bureau of Navigation (now BuPers), that a distinguishing device for qualified submariners be adopted.
He submitted a pen and ink sketch of his own, showing a shield mounted on the beam ends of a submarine, which dolphins forward of, and abate, the conning tower. The suggestion was strongly endorsed by Commander Submarine Divisions, Atlantic.
During the next several months, the Bureau of Navigation solicited Additional Designs from several sources. Among the designs where a submarine and shark motif, a submarine and shield and submarines and dolphins.
A Philadelphia firm, which had done work for the Navy previously, was approached with the request that it undertake to design a suitable badge. Two designs where submitted by the firm and these where combined into a single design. It was the design in use today, a bow view of a submarine, proceeding on the surface, with bow planes rigged for diving, flanked by dolphins in horizontal position with their heads resting on the upper edge of the bow planes.
On 20 March 1924, the Chief of Navigation recommended to the Secretary of the Navy that the design be adopted. The recommendation was accepted by Theodore Roosevelt, Acting Secretary of the Navy.
The submarine insignia was to be worn at all times by officers and men qualified in submarine duty attached to submarine units or organizations, ashore or afloat, and not to be worn when not attached.
In 1941, the Uniform Regulations were modified to permit officers and men who were eligible to wear the submarine insignia to wear that insignia after they had been assigned to other duties in the naval service, unless such right had been revoked.
The officers' insignia was a bronze, gold-plated metal pin, worn centered above the left breast pocket and above the ribbons or medals. Enlisted men wore the insignia, embroidered in silk, in white on blue for blue clothing and in blue on white for white clothing.This was sewn on the outside of the right sleeve, midway between the wrist and the elbow. The device was two and three-quarter inches long.
In 1943, the Uniform Regulations where modified to provided that "enlisted men, who are qualified for submarine duty and are subsequently promoted to commissioned or warrant ranks may wear enlisted submarine insignia on the left breast until they qualify as submarine officers, at which time this insignia would be replaced by the officers submarine pin."
In mid-1947, the embroidered device shifted from the sleeve of the enlisted men's jumper to above the left breast pocket.
A change to Uniform Regulations dated 21 Sep 1950 authorized the embroidered insignia for officers and a bronze, silver-plated, pin-on insignia for enlisted men.