Here the keel itself is relatively short in comparison to the length of the waterline and the rudder is positioned well aft of the keel. Since the amount of surface area under the boat is minimal, there is less friction being produced, less drag, and therefore it reaches hull speed quicker. Because of the above mentioned characteristics, the fin keel boat is a sportier design and is preferred over full keel boats for performance racing. The full keel boat, has a slightly different underbody. Usually it is a bit slower - There is more friction being produced due to added surface area moving through the water.
Friction is the greatest handicap in light wind conditions.
When winds are strong enough to achieve hull speed the Full Keel boat can sail as fast as other boats. Slower to turn - Deflection of water off the rudder is not as clear. It takes a little more room to turn a 360 degree circle. Full keel boats are also more difficult to steer when operating in reverse. Directional Stability - With a large projected vertical surface area, the full keel is said to keep the boat sailing in a straight line.