Page 40 - Eric C. Fry - Knots and Ropework

21 The most efficient method of attaching the bight of a rope, or a
sling to a hook, provided that both standing parts are under load.
It will prevent the hook sliding along the rope and thus ensures
Cat'sPaw that the load. ego a spar, will be lifted horizontally. Conversely, by
careful selection of the position of the eat's paw in relation to the
length of the sling, the load may be lifted at any required angle.