A dismasted sailboat (keelboat) will be adversely affected. This is a well-established fact as discovered and confirmed by some of the leading minds in sailing while investigating the Fastnet '79 disaster. Think of a metronome. Now remove the counterweight and cut the long stem off. With only the lower pendulum, that thing wiggles back and forth in maniacal fashion. Basically the same principle. The mast and rigging weigh less than the ballast, but exert a leveraging force to slow the motion against the force of the ballast. The effect will vary with each design, but the change is a fact.