'Sailor heaving the Lead' - by John Augustus Atkinson (c.1775– c.1831) published in 1807. - A selection of images from the archives of the Hull History Centre and elsewhere relating to the work of the Missions to Seamen. [Hull History Centre File Reference : U DMS/7/15] [1389]

'Heaving the lead' is an ancient procedure especially for sailing vessels where the 'leadsman' swings a lead weight and line overboard which has been marked in fathoms in order to estimate the depth of water under the hull of a vessel when entering a tidal harbour such as that at the River Ely Tidal Harbour. The variables being the state of the tide, wave height, wind intensity, dynamics of the vessel such as rigging, speed, pitch and roll etc., combined with the depth of the hull below the waterline and dependant upon the weight and position of the cargo in the hold and on deck.

The lead line was normally marked in fathoms, or parts thereof, (1 fathom = 6 feet) so the depth can be seen during daytime or felt at night. Markers attached to the line alternated between leather, cloth, and knotted cords to assist the 'leadsman' to report to the helmsman safety of passage or otherwise!