All I know is that there have been "a lot". I doubt if we will ever have a close count.
However, I can address the replacement of Sonarman comment.
(From "Our Book"):
1957-60: Sonarman rating (SO) personnel are replaced by Ship Servicemen, Cooks, Storekeepers and Boatswain Mates at completion of their current NavFac tours (we "Sonarman" had started at the very beginning – 1954).
It was in late 1957 that the Navy decided to return the Sonarman to their normal sea going billets and that the NavFacs would be manned by Ship Servicemen, Cooks, Storekeepers and Boatswain Mates for their shore duty tours. This is how Steve Davis and I found ourselves transferred to the USS Weatherford (upon completion of our present tour at Shelburne).
This proved to be a poor decision and the Navy soon realized that they needed to return Sonarman to NavFacs and try to establish continuity and longevity required for system proficiency (i.e., job code).
Steve Davis and I were approached (closed door session) by a Navy Commander who had been sent to the ship (by CDR Joe Kelly USN and LT Fred Jones RCN) to see if we would be interested in returning to a NavFac upon completion of this current sea tour.
We both agreed, and soon found ourselves at NavFac “San Salvador” for a one year unaccompanied tour (thank you very much Joe and Fred - Ha-Ha). Ed Smock