In 1905 'London to the Nore', written by Wyllie's wife M.A. Wyllie, was published by A & C Black, illustrated with 60 colour plates, reproduced from Wyllie's watercolours, and 28 black and white head and tail pieces. The book describes the places encountered from Westminster to Rochester during cruises on their Thames sailing barge, 'The Four Brothers'. This watercolour is one of the illustrations and its subject is described in the text:

'Next we come across the six obsolete gunboats that are permanently moored across the river from a little above Port Victoria to the mouth of Stangate Creek. The boom consists of four steel wires supported by floats between the ships, with the lower wires snaked to the upper ones, so that when the boom is in position the wire looks some six or eight feet above the water, besides the portion submerged, forming a tremendously strong barrier across the Medway, a barrier that no torpedo boat could pierce. At either end the boom is defended by batteries of long guns on the banks, aided by powerful searchlights. Ships of the Reserve Fleet, with nucleus crews on board, are moored above the boom for emergency.'

M.A. and W.L. Wyllie, ‘London to the Nore’ (London: A & C Black, 1905)