[Of uncertain derivation: it has been suggested that cont is a variant of CANT sb.1]
1. The spiral intervals formed between the strands of a rope, by their being twisted together.
1848. G. Biddlecombe, Art of Rigging, 10.
1874. Knight, Dict. Mech., 612. Cont-line in worming is filled up with spun yarn or small rope, which brings the rope so treated to a nearly cylindrical shape.
2. The space between the bilges of two casks stowed side by side.
1867. Smyth, Sailors Word-bk.