A port side view, taken from well abaft the beam, of a Port of London Authority wreck marking vessel at moorings close to a wreck on the River Thames off the entrance to Tilbury docks, Essex. The boat is a wooden, single masted, gaff rigged sailing vessel and her dinghy is on a painter astern. Two men in a rowing boat are standing off and a single wooden spar is sticking out of the water. A pier is in the right background and a building has Rait & Gardiner on it. Two steamships, one owned by Ellerman Lines, are in docks in the left background.