Ilfracombe is a charming little port on the North Devon coast in England. Close to its bustling harbour is the base of the local scuba diving club, who have a large and active body of members. Many are keen wreck divers, and the busy but treacherous waters off Illfracombe provide rich pickings for their amusement. Over the centuries, numerous ships have foundered on this coastline, as the dive club’s bar bears witness. It is an Aladdin’s cave of maritime artefacts. Portholes and valves, ships telegraphs and wheels stud the walls, while smaller items crowd the window sills. In one corner, near to the back, are a number of dull grey conical objects. They generally have a round depression in the bottom, and a hole through where a line would once have been. In spite of their modest size, they can catch out the unwary who idly pick them up. Made of solid lead, that are surprisingly heavy - generally about fourteen pounds. These are ships’ leads that have been lost over the years by vessels probing their way in and out of the harbour.
Leads, or plummets, have been used for centuries by mariners as a crude but effective way of measuring the depth of the sea. A sailor would be placed in the bows of a ship, normally in the fore-chains on the weather side, and given a lead attached to the end of a twenty five fathom line, with the various depths marked on it. The depression in the bottom of the lead could be filled with sticky tallow, if the nature of the sea bed needed to be ascertained. In times of poor visibility, the material that stuck to it (sand, mud, shingle etc) could provide clues about location. As the ship progressed, the lead was swung in a circle to gain momentum, and then thrown ahead of the bows. When the vessel passed over the lead as it rested on the seabed, and the line was vertical, the depth could be read off. Once this was done, the rope was hauled back onboard for the next cast.
This was highly skilled work, which had to be carried out accurately in all weathers, including at night. Because use of a lead normally only happened when the ship’s captain was uncertain of his location, a wrongly reported depth could prove disastrous. The line used had to be marked in a way that could be interpreted by a sailor, who in many cases would have been illiterate, and in any event might have to rely on feel alone on a black night. Over the years a system was devised that used markers made from materials in a variety of both colours and textures, attached to the line at the various depths. For example, ten fathoms was shown by a square of leather with a hole in it, while twenty fathoms was marked with a knotted cord. In addition to leather and rope, white canvas, red bunting and blue serge were used in various combinations to denote other depths. Each material had both a different appearance in daylight, and a unique shape and feel in the dark.
Shortly after the end of the First World War, the first echo sounders were produced, using the time taken for a sound to bounce back off the seabed to determine depth, and as they became more widely available, the days of using a lead line were numbered. Now commercial echo sounders are freely available for even modest sized boats. Sailors no longer need to use lead lines, but the shadow of this long-dead practice still exists in the English language.
The accusation that someone is “swinging the lead” means that they are appearing to work diligently, when in reality they are not achieving anything. Its nautical origins are clear, but at first glance it seems to be a rather strange expression to apply to the leadsman of a ship. As we have seen, working a lead was both skilled and responsible work. However, it was also physically demanding, and the person performing the task often became soaked through as they hauled large quantities of wet rope back onboard. The task had two components to it. First, a period of swinging of the lead to generate the momentum for a cast, rather like a cowboy with a lasso. This was showy, but relatively comfortable and dry work. The second part was the actual cast and hauling in of the line, together with its heavy weight. It would have been tempting for a tired or lazy seaman to reduce the number of casts he needed to perform by devoting more time to the first part of the operation than the second, earning them the accusation that they were “swinging the lead”, rather than casting it.