Abstract: A system for automatically modifying the lean of a catamaran during a turn includes a pair of fins, each substantially permanently affixed to the inside edge of the left and right hull, plus a pair of vertically displacing plates that extend, one at a time, from the left or right hull, into the body of water. Individually, the fins or plates modify the lean of a catamaran during a turn such that the tilt is neutral or inboard, versus outboard without either. The cumulative effect of using both is substantial and synergistic.

Abstract: A system for automatically modifying the lean of a catamaran during a turn includes a pair of fins, each substantially permanently affixed to the inside edge of the left and right hull, plus a pair of vertically displacing plates that extend, one at a time, from the left or right hull, into the body of water. Individually, the fins or plates modify the lean of a catamaran during a turn such that the tilt is neutral or inboard, versus outboard without either. The cumulative effect of using both is substantial and synergistic.