The enlisted rate insignia of World War I were governed by the Uniform Regulations of 1913 and subsequent revisions. The enlisted structure of the Navy, at that time, was still evolving from its nineteenth century origins. Petty officers and non-rated men were grouped into classes, but there were not yet standardized pay grades as we think of them today. Not every rating had rates in every class; a few titles had only one petty officer rate.
The overall shape of the rating badge was not standardized at the time, and sailors often cut the backing material into decorative shapes. The rating badges in the following tables are illustrated in a rectangular format, similar to the way they were presented in the uniform regulations.
In March 1918 the first rating badges for petty officers assigned to naval aviation were authorized. To accommodate the wider winged specialty marks, the eagle was spaced a quarter of an inch higher than on standard rating badges. This was most visible in the arch for chief petty officers.
Petty officers wore their rating badges on one sleeve of their uniforms: the right side for the seaman branch, and the left side for all others. The Geneva cross of the pharmacist's mates was red on both blue and white backgrounds.
Gold stripes with silver embroidered eagle and specialty mark: Worn on blue clothing by petty officers with three consecutive enlistments with good conduct.
Red stripes with white eagle and specialty mark: Worn on blue clothing by petty officers not entitled to gold stripes.
Blue stripes with blue eagle and specialty mark: Worn on white clothing.
Red stripes with blue eagle and specialty mark: Worn on white clothing before Uniform Regulations of 1913, which changed the stripes to blue. Authorized to be issued until supplies were exhausted.
Pharmacist's Mate 1st Class with red specialty mark for white clothing.
Seaman Branch (right sleeve)
Artificer Branch (left sleeve)
Special Branch (left sleeve)
Chief Petty Officer
Chief Boatswain's Mate
Chief Turret Captain
Chief Gunner's Mate
Chief Machinist's Mate, Chief Water Tender, Chief Special Mechanic 
Personnel below petty officer grade were termed "non-rated," and were divided by the navy into "seaman" classes, even though not all held the title of seaman. Seamen wore a "branch mark" around the right shouder seam of their jumpers, white on blue uniforms and blue on white. Firemen, the non-rated men who worked in vessels' engine rooms and fire rooms, wore a branch mark on the left side, which was red on all uniforms.