Oakum

Oakum is a preparation of tarred fiber used in shipbuilding, for caulking or packing the joints of timbers in wooden vessels and the deck planking of iron and steel ships, as well as cast iron pipe plumbing applications. Oakum was at one time recycled from old tarry ropes and cordage, which were painstakingly unraveled and taken apart into fiber; this task of picking and preparation was a common penal occupation in prisons and workhouses.