Quite a number of the Royal Navy's seaplane carriers (precursors to aircraft carriers proper) during WW1 were converted ferries. Some of which would have had radial davits as mentioned earlier by Jim.
The chap seated on the right with the handkerchief in his pocket has a colour between his rings, he must be either an engineer (purple) or a surgeon (red).
Btw if you look under the chair of the bearded man you will see a dog !