The men in uniforms are Royal Navy Reserve officers, probably on board an armed yacht. The crews of requisitioned vessels often stayed with their ships; in many cases they were the only people familiar with the idiosyncrasies of the sometimes elderly vessels involved. Note the semaphore on the bridge wing and just below it on the deck a small gun; probably a 2 or 3pdr. WW1 [John Collins]
From Howard Goodwin negatives. Glass negative - 3.25 x 4.25 (Quarter Plate).
Date: c1915