In his introduction to Wyllie's 'Sketch Book' published in 1908 – a sequel to 'Marine Painting in Water-Colour' (1901) – the artist Edwin Bale explained the significance of unfinished sketches like this one:

'Sketches are not unfinished pictures to be carried on and completed; they are slight works complete in themselves - notes, jottings - giving as much of fact and time as time and circumstances allow or their ultimate use demands. They are partial statements or representations, in which the important facts are put down in a broad and simple way, permitting of amplification and future use... They should be jottings of important points only, and eminently illustrative of the art of leaving out.'

W.L. Wyllie, ‘Sketch Book’ (London: Cassell & Company Ltd., 1908)