DAGGERBOARD

The disadvantage with a daggerboard is its vulnerability to damage if you hit something that is under the water. The centreboard, on the other hand, pivots on an axle so that if you hit anything the clamcleat holding the downhaul in place bursts open, as it is designed to do, releasing the downhaul and allowing the centreboard to flip from vertical to horizontal with no harm done. A daggerboard would either break or if badly designed (too strong) it could even slice through the hull.