From its creation in 1915, until 1974, the United States Coast Guard adopted the uniforms of the United States Navy. These included the dress blue jumper and trousers to working dress uniforms. In 1974, to differentiate themselves, the Coast Guard created the Service Dress Blues.
Shown on the left of the above photo, the Service Dress Blues, or SDB, are based on the uniforms of the US Life Saving Service, which was incorporated into the Coast Guard in 1915.
It consists of a four pocket single breasted jacket, with matching tie and trousers and light blue pointed collar shirt, with rank insignia on the collar. It is finished with a white peaked cap displaying a junior enlisted badge.
On the right, is the US Navy’s Enlisted Service Dress Blue uniform from 1916. It was a dark blue, almost black, wool jumper, with neckerchief and white undershirt. They were worn with matching 13 button trousers, and a wide brimmed flat cap with a silk ribbon tally bearing the name of the sailor’s ship.
100 years ago, these two men would have been in almost identical uniforms. The only difference would have been a small shield on the lower right sleeve of the Coast Guardsman. Also, his hat tally would have started with USCGC (U.S. Coast Guard Cutter) instead of USS (United States Ship).
One thing did not change much over the past century; the rating insignia.
On the left, the Coast Guardsman wears the insignia of a Damage Controlman 3rd Class. This rate was created in 1948, combining the Carpenter’s Mate and various other rates.
On the right, the sailor is wearing the insignia of a Gunner’s Mate, 3rd Class. It is one of the oldest rates in naval history, dating back to the age of sail.
Both these rates and ranks are displayed by a single chevron, below a rating badge suspended under an eagle.
Uniforms have changed a lot over the past 100 years, but veterans have not. You all make a great sacrifice, day in and day out.