Established in 1948 from the Special Artificer Optical (SAO) rating, the Opticalman (OM) rating and the tasks associated with it were so specialized that it was only a matter of time before the U.S. Navy disestablished it and folded its duties into that of another rating. But the rating actually lasted for years, only being disestablished along with the closely related Instrumentman rating in 1999.
As the name implies, the world of the Opticalman revolved around optical tools. In the Navy, optical devices can be divided into three broad categories—microscope, telescope, and periscope—and any piece of Naval optical equipment falls into one of those groupings or is derived from a combination of the two. Examples of this core principle are listed in the 1989 edition of the Opticalman Training Manual (NAVEDTRA 10215). A binocular, for instance, is really two “telescopes” placed side by side so you can look through them simultaneously with both eyes; a gunsight scope is a telescope attached to a gun barrel.
Keeping the fleet’s optical equipment in top condition fell to the Opticalman—not a light burden because of the sensitive nature of many of the instruments meant that the smallest oversights in alignment, grinding, or maintenance could render them useless. The cramped confines of combat vessels meant that most Opticalmen were assigned to shore facilities or repair ships.
Instrumentmen (IM) worked on watches, clocks, sextants, typewriters, and other types of office and nautical equipment. With the disestablishment of both the OM and IM ratings in 1999, the Sailors who had served in those careers banded together to form the OM-IM Association, which bills itself as the brotherhood of the U.S. Navy's Opticalman and Instrumentman ratings.