When I get my new printer with a scanner working, I will be able to upload some more info, but the F/T group had 3 main type of variety, plus the special groups, such as the Diving tenders with a fixed diving chamber. They where type A which is only fitted for the carriage of cargo, type B which is fitted to carry ether cargo or passengers, type C which is fitted to accommodate 12 R.F.A. personnel for training purposes. I believe the type A also where designed to carry a 21" torpedo on deck, these where the ones with a Derrek, but they also carried passengers in large numbers when required. The type B did not have any Derrek but had a large open hatch forward with stairs going down into the hold, with a large canvas cover over it to protect passengers from the weather. I know mainly about the RMAS ones which where the majority, as I used to navigate around the coast. They where manned by a boatswain in charge with 2xAB's and a Mechanician in charge and I believe a stoker, the Boatswain used to run the boat in it's designated area but if it had to move else where which necessitated a coastal voyage a mate was employed to move it.