Thresher (SSN-593). Emblem adopted in 1960 and received in
October of that year. It was accompanied with this description: The fish
depicted in the subject insignia is a Thresher shark, which is
characterized by a tail that is approximately one-half of its total length. The
Thresher shark reportedly attacks its prey by flailing the long
tail. The horizontal lines signify the deep diving capability of Thresher. The circles represent her sonar capability.
The motto, 'Vis Tacita',
describes the overall characteristics of the ship, 'Silent strength'.