Oakum

n.	1.	The material obtained by untwisting and picking into loose fiber old hemp ropes; - used for calking the seams of ships, stopping leaks, etc.
	2.	The coarse portion separated from flax or hemp in nackling. White oakum that made from untarred rope.

Noun

1.

oakum - loose hemp or jute fiber obtained by unravelling old ropes; when impregnated with tar it was used to caulk seams and pack joints in wooden ships

fiber, fibre