The Friction Contract

The friction contract is this site's name for the set of grip points that keep a knot tied: each place where rope presses on rope is a clause, and a knot fails when one of its clauses gives way.

In a square knot

In a square knot, the main clauses sit where the two bights meet. Each rope doubles back into a bight, a U-shaped bend, that wraps round both the standing part and the working end of the other rope. In the site's drawings, both bights lie on the same side of the other rope's two parts: one passes over both, the other under both. In a granny knot, tied with the second throw the same way as the first, each bight passes over one part and under the other. Square knot vs granny knot numbers all six crossings and sets the two knots side by side.

Limits

Rope signs nothing; the contract is a way of reading a knot, and the friction is the real part. Knot pages that use the term still name each grip point in plain mechanical terms, such as where the rope is pinched and where it bends hardest, and they give no strength figure unless a named study supplies one with its test conditions. See Which layer was checked for how knot diagrams are checked.