If you're referring to Sonar personnel such as myself, Sonar on most Fast-Attacks comprised of a division of about 12-15 Submarine Sonar Techs (STS). All Sonarmen were minimum 6 year enlistees, as Basic Sonar and Advanced Sonar typically took around 18 months from Boot Camp to their first afloat command. That included BT, Submarined School, Basic Sonar, Basic Electricity/Electronics, and Advanced Sonar Maintenance. A Sonarman's desired career path generally chooses which systems he'll train on for advanced training since FBM and Fast-Attacks typically have different systems, and they have different missions. For a true Sonar career, a Fast-Attack is the only real choice.
Sonar watch comprises several crewmembers, who are overseen by a Sonar Supervisor. The Sonar Sup is typically a 2nd or 1st class STS, and has been through advanced acoustic and sonar training, as well as having been a veteran of key deployments. Aside from the Contro Room personnel, the Sonar Supervisor is considered one of the most important underway submerged positions on the boat, being responsible for reporting the acoustic tactical situation to Control.
Under normal watch, Sonar was comprised of the Supervisor, Passive Operator (primary) Passive/Active Operator (normally run in secondary Passive on the Active console), Narrowband and Auxiliary systems Operators. Watch was rotated between personnel so ears remained fresh, and most importantly for coffee runs. For Battle Stations or Tracking Parties (key targets), typically senior Sonarmen were assigned to the main consoles in Sonar, while others were assigned to Damage Control duties. I was the Primary Passive Sonar Stack operator during Battle Stations on my boat for about 2 years, the key operator for the boat. "Hot Seat" doesn't even come close to a description during those days.
If you're referring to Sonar equipment, the Sturgeon class and its variants were initially outfitted with the BQS-11/12/13 Series Sonar suite and BQR-7 as its primary sonar systems. After upgrades, all boats were eventually outfitted with the BQQ-5 Sonar Suite, which was an Analog/Digital hybrid of the original BQS-13 system. The other significant upgrade was a retractable Towed Array - original boats had a fixed TA which had to be deployed by a support Mike boat when the boat left port, and manually hauled in by a support boat when it entered port. This limited a boat's port call choices. LA Class boats were outfitted with the BQQ-5 system from the start, receiving upgrades as time went on. The biggest difference between the BQS-13 and BQQ-5 is that the 13 system was primarily an analog system, with fixed Passive and Active consoles. The Q5 was a computer core driven system that could load any stack program into any one of the consoles, though the configuration was typically standard throughout the fleet based on previous BQS-13 layout.
Few jobs in the Submarine Force at the height of the Cold War were as cool and stressful as being a Submarine Sonarman on board a Fast-Attack. I experienced things before I was 30 that few people ever think about. My own cousin followed in my footsteps about a year after I joined the Navy - he was a Sonar Tech in my Squadron on another boat, and a good one to boot.
To give you an idea of what we were required to learn, aside from the electronics maintenance and repair aspect, I remember going to a class called "Enlisted Sonar Principles". Naturally, those of us who went figured it was going to be a gravy week. That was blown when we walked in and saw 2 notepads, a box of #2 pencils and a Math textbook. As it turned out, the course was how to perform by hand all of the oceanographic geometry and math calculations that the Sonar systems do automatically, accounting for all physics and enviromental variables. To this date it is the hardest course I have ever taken.
If you saw Hunt for Red October, it's not even close to reality as far as Sonar goes. Though I can't confirm or deny any events in Blind Man's Bluff (I'm still bound by security oath), I can say it's a "fairly accurate" account. While I and others of that era aren't happy with how the Submarine community has opened up some of its secrets, there is at least some material that my family can read to get an idea of what I used to do that I've never been able to specifically tell them about.
You should also Google AZORIAN or Project Jennifer, which are the names of the CIA sponsored project to raise the Soviet Golf II submarine K-129 using the Hughes Glomar Explorer. A DVD was released last week documenting the project, which took place in 1974. It shows you the lengths at which our nation was willing to go to maintain the acoustic edge over the Soviet submarine fleet.
If you're wondering, my old boat was USS RAY (SSN-653). Though now gone, it was then the most decorated boat in the Atlantic Submarine Fleet. You can see some pics on my bio page.
