Different Draft
Rick, The difference is whether you have a deep or shoal draft keel. We have the shoal draft 4'6" keel and it has a bulb with little fins. The bulb is to add weight at a greater mechanical moment and the fins are for hydrodynamic stability. My former Catalina had a big wing at the bottom of its shoal draft keel - using the flow of water over the wing to keep the boat upright. When you have room for a deep fin, you don't need either system. Barry H33 #128 Bear Necessity
