SWING THE LEAD - ORIGIN

The "chains" of the ship is just a reference to the bow, where the anchor chains were found. The sailor on the lead duty was stationed there and threw the lead forward of the ship, counted the knotted markers on the rope as it slipped through their fingers, and when the line was vertical reported the depth. I don't think your great uncle was doing some sort of exercise on chains. I think he was actually measuring the depth of the water using lead and line. Can be fairly vigorous exercise depending on how often you throw the lead (and how deep the water is), and sailors on this duty were given extra clothing because it was potentially wet work. I think the lead would still be in use in 1914 as a reliable way to measure depth. I don't think acoustic methods were particularly accurate at that time, and certainly would not be directional so the ping sound would be a dead giveaway to a nearby submarine that something high tech (for the time) was nearby.

I have been reading my Great Uncle's life story, he was a sailor on board H.M.S. Gloucester , he has written another explanation for the phrase 'Swinging the lead '. He had written this 'I remember Christmas Day 1914, I had been in the chains swinging the lead because I was that cold.' So I wonder if the phrase may not only be used for laziness but because the sailors when they were on board ship used the chains on the ship to make themselves warm by swinging on them and called that swinging the lead.
Peta Bradley