A good whipping bind will hold for a spell, but when you need grip, turn to your stoppers and hitches. Any sailor worth his salt knows better than to use a thumb-knot on any strand of rigging!
For the stoppers, their use is best left to punishment-types. A good lash will take more than its share with a few of the buggers worked into it! Let no sailor question the words of a fellow with a nine-tails at his side.
But the true gem of knots is the faithful hitch. It grabs and holds, but gives easily to a trained hand. Neither wind nor rain will cause it to falter. Learn it well, young sailor, for it will be your only steadfast companion on the treacherous sea.
