"SS" is a warfare specialty designator, signifying a sailor is "Qualified in Submarines". The "SS" itself stands for "Submersible Ships", not "submarine sailor" as many people incorrectly assume.
"SS" designation also comes with its own warfare insignia pin, worn as silver (enlisted) or gold (officer) dolphins abreast the bow of a submarine.
Submarine qualification takes most sailors about 8-12 months, depending on their particular rate and workload aboard ship. Nuclear rates typically take less time, since part of their nuclear training is at a shore station nuclear power plant that is similar to a shipboard reactor.
Unlike other warfare designators (Surface, Aviation), it is mandatory for all submarine crewmembers, be it the lowest ranking sailor or the Captain, to qualify in submarines. Qualification is heavily weighted toward damage control during a casualty.
The rate designation is added at the end of the rate; e.g., my old rate designator was STS1(SS), which fully written out would be "Sonar Technician(Submarines) First Class (Submersible Ships).
Possibly a Flight Engineer
I haven't heard that term when relating to the US Navy. But in the Royal Navy SDG is a scubadiver
Yes. The Enlisted rate for medical personnel in the Navy is Hospital Corpsman (HM)
MOS would be most interchangeable with Rate in the navy. Rate is pretty much another word for job specialty as is mos. Rate may also be referred to as a NEC.
This is called a "rating" in the Navy. The AT denotes that person's rate, or job. In this case, it is an Aviation Technician. The 3 denotes that person's rank, which in this case, is a 3rd Class Petty Officer.
ETC is an enlisted rating in the US Navy. The ET denotes the skill set Electronics Technician. The C denotes Chief Petty Officer, an enlisted grade E-7. The SS designates Submarine Qualification. The ETCS designates a Senior Chief E-8, An ETCM designates a Master Chief E-9. E-9s are the top enlisted rank in all US military services. As a further example in the USN MMCM(SS) would designate that this is a Machinist Mate Master Chief and a Qualified Submariner.
SS is short for Steam Ship and used on civilian ships. NS would be Nuclear Ship and there was at least one civilian nuclear powered vessel. US Navy ships carry the prefix of USS for United States Ship. British Navy ships have HMS for Her Majesty's Ship.
"Rate" refers to a non commissioned member of the US Navy.
1949
submersible boat
SEa Air and Land
Not SSK3c, but SK3c is the old rate designation for Ship's Storekeeper, 3rd Class. The Storekeeper rate, one of the oldest in the Navy, has always used the designator SK. Today the rate/rank would be designated SK3.