Pay Grade E-4 (enlisted 4), the lowest rank of a noncommissioned officer (NCO), the same as a corporal in the US Army or Marines. Just above Seaman and below Gunners Mate 2nd Class. Its a type of Petty Officer.
The Navy's system is a combination of "rating", (here Gunners Mate) and "rate" (here, Petty Officer 3rd Class) and they are combined into "Gunners Mate 3rd".
Petty Officers in the Navy have specialized training, and there are a large number of rates, each with its own special insignia.
All Petty Officers wear a sleeve insignia showing their rating and rate. At the top is an eagle, above the insignia of their specialty - for a gunners mate, two crossed cannon. Below that are upside down chevrons (compared to the way an army or marine sergeant wears his). One chevron below is 3rd class, two is second, petty officer first class.
On January 8, 1942, Technician Third Class (T/3), Technician Fourth Class (T/4), and Technician Fifth Class (T/5) were added to the rank insignia. On September 4, 1942, a "T" was added to the standard chevron design that corresponded with that grade. A technician was not addressed as one such, but rather as the neighboring rank in its pay grade (T/5 as Corporal; T/4 as Sergeant; T/3 as Staff Sergeant). A technician did not have the authority to give commands or issue orders. http://en.wikipedia.org/wiki/United_States_Army_enlisted_rank_insignia_of_World_War_II
"Tech" SGT (Technical Sergeant).Tech 4 Class had 3 stripes similar to Sergeant rank but had a "T" under the stripes. The "T" indicated a rank based upon sepciality training and did not carry the command responsiblity.There were also a Tech 5 Class(2 stripes) and a Tech 3 Class (4 stripes).A Technical Sergeant was a rank with 5 stripes and without a "T".Link: http://www.tioh.hqda.pentagon.mil/rank_page/history_of_enlisted_ranks.htm
PHM3 in the US Navy during WW II means that a sailor is a Pharmacists Mate 3rd Class. Enlisted Grade of 4. This rate and rank usually served as a Medic. Some in hospitals, some aboard ships and some attached to Marine Infantry units.
Most generals wore a double-breasted tunic or a long frock coat. Their uniform was dark blue and usually had their rank worn on their epaulets. The Confederate officers wore their rank embroidered on their sleeve and on their collar.
RD3 - RD=Radarman (Rate) - 3=3rd Class Petty Officer (Rank), no longer exists
First Class Petty Officer is the Rank; the paygrade is E-6.
fireman third class (lowest starting rank)
"HM" is the Navy rating for a Hospital Corpsman; the 3 means he/she is a 3rd Class Petty Officer.
Mm2c is the old (WWI/II) rate designation for a Machinist's Mate Second Class. The modern equivalent is MM2. In both cases, the rank is a 2nd Class Petty Officer (E-5).
S-3 stands for seamen third class.
Rank is a term that references longevity and seniority. Rating is the term used for the type of work an individual does. While COX would typically be a rating, when it was used, it was one of the only terms that specifically identifed both a rating and a specific rank. COX is the abbreviation for Coxswain. The individual would be an E-4 Boatswain's Mate. Today we would call that a Boatswain's Mate Third Class (BM3). In today's Navy the term is used to refer to any individual running a small boat or landing craft and doesn't refer to a rank or a rating.
Rank is a term that references longevity and seniority. Rating is the term used for the type of work an individual does. While COX would typically be a rating, when it was used, it was one of the only terms that specifically identifed both a rating and a specific rank. COX is the abbreviation for Coxswain. The individual would be an E-4 Boatswain's Mate. Today we would call that a Boatswain's Mate Third Class (BM3). In today's Navy the term is used to refer to any individual running a small boat or landing craft and doesn't refer to a rank or a rating.
Patternmaker third class see : http://www.navy.mil/navydata/navy_legacy_hr.asp?id=263
It is an individual that has attended Signalman (SM) A-school in the United States Navy and also achieved the rank of E-4 (Petty Officer Third Class). When the rating (job) and rank are combined, one would use the term Signalman Third Class (SM3). As a side note, the rating of Signalman (SM) was merged into Quartermasters (QM) in 2003.
Percentile rank
The same then as it does today: Electrician's Mate First Class. The only difference is that today there are Nuclear EM's as well as conventional ones.
"Petty Officer" is not a job description, but a rank. It is the lowest US Navy rank for an NCO, (Non-Comissioned Officer). The job description would be called the "rate" or "rating" such as gunner's mate, machinist, storekeeper etc.