see it clearly

Double Strop Knot

The double strop is used for large blocks; it gives more support to the shell than the single strop and admits of smaller rope being used. Wire rope is much used for block strops; the fitting is similar. Metal blocks are also used in fixed positions; durability is their chief recommendation. Great care should be taken that they do not chafe the ropes which pass by them as well as those which reeve through.

How to Tie a Double Strop Knot

Made with one piece of rope, the splice being brought as usual to the crown of the block 't', the bights fitting into scores some inches apart, converging to the upper part, above which the thimble receives the bights 'a', and the four parts of the strop are secured at 's', 's' by a round seizing doubly crossed. If the block be not then on the right slew (the shell horizontal or vertical) a union thimble is used with another strop, which produces the desired effect; thus the fore and main brace blocks, being very large and thin, are required (for appearance) to lie horizontally; a single strop round the yard vertically has a union thimble between it and the double strop round the block.

Double Strop Knot tying illustration