Two detailed directories of interest are available online. Royal Navy Senior Appointments with some data going back to 1859; it includes present appointments as well. Appointments are not just at the top levels but include various departments within the Royal Navy; i.e. Controller of the Navy, the Torpedo Division, etc. The second list – Captains Commanding Royal Navy Ships – features commands back to the mid-1860s and is broken down by type of ship.
Royal Navy Command Lists