Slamming

Slamming is the impulsive impact pressure when a flat or flared bow bottom re-enters the water surface after emerging in a seaway, producing a sharp local load and exciting transient hull-girder vibration (whipping). The pressure depends on relative vertical velocity at impact and deadrise angle. Masters reduce speed or change heading to limit slamming; structurally, the bottom forward is reinforced and the whipping bending moment is added to the wave-induced moment.