A painting showing the hulk of the wooden frigate 'Leonidas' anchored near Upnor on the Medway in Kent. The coastline is visible in the distance on the left. The 'Leonidas', 36 guns, was launched in 1807 and by 1872 had ceased active service to become a powder hulk storing gun cotton. By the 1880s, with the coming of steel and steam power, many of the old 'wooden walls' were being used in naval anchorages for such purposes. Those in the Medway, off Chatham and Sheerness Dockyards, were a familiar sight to Wyllie whose home was nearby.

The hulk of the ship looms up with the crowned, head-and-shoulders figurehead of Leonidas on the bow. Leonidas was the Spartan king who died defending Greece in 480 BC by holding the pass at Thermopylae against a huge Persian invading army. His small Spartan force was eventually outflanked by treachery, refused to surrender and fought to the last man. The carved head of a lion on the ship also denotes Leonidas. There is a red flag fluttering on the hulk with a weather vane on top of the flagpole pointing towards the left. There are figures on the companionway gesturing towards the smaller craft heading towards the hulk to collect gun cotton. These are Thames sailing barges with their masts and sails lowered, under tow as a connected string from a small steam tug in the left background. The tow lines connecting them are clearly visible.

The approaching vessels have been caught in a squall denoted by the bargeman standing up left of centre and hurriedly putting on his oilskin jacket. The craft in the foreground is known as a doble, used for smelt-fishing in the Medway. The second barge from the left has the name 'Providence' painted on the stern. This vessel appears in several sketches by Wyllie and the inclusion of the word 'providence' suggests that these boatmen are dependent on fate. A ray of sunshine briefly illuminates the ship's side and floods it with light, while the rest of the hull and surrounding water is darkened by the lashing rain. The artist has used the squall to show man's endeavour in the face of the elements, and has concentrated on the effects of light on the side of the hulk and on the water.

The atmospheric treatment of the subject owes a debt to the work of J. M. W. Turner (1775-1851). The theme of the transition from sail to steam, the effects of weather on the hull and the general style also acknowledge the earlier artist's subject matter. Wyllie has fused a synthesis of artistic concerns with a social commentary on men working in boats on the river, and the effects of technical progress.

The atmospheric treatment of the subject owes a debt to the work of J. M. W. Turner (1775-1851). The theme of the transition from sail to steam, the effects of weather on the hull and the general style also acknowledge the earlier artist's subject matter. Wyllie has fused a synthesis of artistic concerns with a social commentary on men working in boats on the river, and the effects of technical progress. This painting was exhibited at the Royal Academy in 1885 and the artist also produced a large oil sketch of it (BHC2283). It is signed and dated, lower right,' W.L. Wyllie 1885'.