Two R. & H. Green & Silley Weir mechanical engineers at work in the engine room on board an unknown ship. They are inside the crankcase of a diesel motor and are using a sledge hammer to hit a ring spanner fitted over a nut on a bearing. One man has his foot on the ring spanner and the other is holding the sledge hammer. The location may be any of the docks in the Port of London or in Falmouth.