The sketch, together with PAE1033, represents an exercise in which a simulated attack by torpedo boats wasmade on vessels protected by the guns of Fort Monckton, in Stokes Bay, just west of Portsmouth. In 1879 there was such an exercise, reported in the 'Illustrated London News' of 25 October that year. The fort was named after General Sir Robert Monckton, Governor of Portsmouth in 1779 when its construction commenced: in 1879 it was equipped with various experimental lights including limelight, Wilde's electric light and early searchlights. The two drawings are early examples of work Wyllie did as anillustrator, this one apparently just a study.