Whipping loads due to aft body slamming

This paper describes a method to measure slamming loads on the aft body of a ship model in the towing tank. The method uses a large number of pressure gauges in the flat part of the stern. The impact force is derived from the pressures by integration. Experiments have been carried out on a scaled model of a modern cruise vessel. The model consisted of two segments so that a simplified 2- node vibration mode is simulated. A structural mathematical model was made of the model as used for the tests. The analysis shows that the measured pressures can be used to predict the whipping loads on the segmented model. It is concluded that the measured loads can also be used on a finite element model of the ships construction to predict whipping stresses. Whipping stresses are important for fatigue loads and the extreme vertical hull bending moment.