Submarine Warfare Insignia - "Dolphins"
June 13, 1923, Captain Ernest J. King, Commander, Submarine Division III suggested 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, with dolphins forward of, and abaft, the conning tower.
Over the next several months the Bureau of Navigation solicited additional designs from several sources. Two designs were submitted by the firm, but these were ultimately combined into a single design.
In March 1924, the design recommendation was accepted by Theodore Roosevelt Jr., Acting Secretary of the Navy. Current enlisted submariners may wear either a silver-color metal pin or an embroidered dolphin. The latter is either white or blue, depending on the uniform worn.
Originally, the embroidered insigna was worn on an enlisted man’s right sleeve, midway between the wrist and elbow. Today it is worn on the left breast.