The date shown is 1917-18 and the ships -identified by Wyllie along the bottom, left to right - are the light battlecruiser 'Courageous' (1916), the battleship 'Benbow' (1913), the battlecruiser 'Tiger' (1913) and the battleship 'Iron Duke' (1912). Another warship hull appears far right with a boat boom out. The location is unspecific but the obvious one would be Scapa Flow. The drawing is, at least in part, a weather study after clearing rain, since the remains of a rainbow appear above the water just ahead of 'Iron Duke'.