Meaning of upsetting lever

upset'ting lev"er

Pronunciation: [key]
— Naval Archit. Naval Archit.
  1. the horizontal distance between the center of gravity, acting downward, and the center of buoyancy, acting upward, when they are so placed as to form a couple tending to capsize the boat.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.