On the Launching of Evaluation Capsules From a Ship in Beam Seas. Numerical and Experimental Investigations of Ship Motions, Wave Climate and Capsule Dynamics

Doktorsavhandling, 2005

The process of evacuating a passenger ship in a seaway can be difficult and providedangerous situations for the passengers. The ship motions and the wave climate in thevicinity of the ship are factors that influence the launching process. This thesis investigates the problem of launching evacuating equipment from a ship with no forward speed in beam seas by using numerical models and experimental tests. The wave climate close to the ship is examined by using a numerical model based on a boundary element method in the frequency domain. Experimental model tests have also been performed to further investigate the surrounding waves. The numerical method to calculate the waves has been implemented into a numerical model where the process of launching evacuation equipment is calculated. This model includes the mother ship motions. These motions are calculated using a strip-theory approach. The dynamics of the evacuation equipment are calculated in the time-domain and the results are validated by comparing against experiments. An extensive study of the influence of several launch parameters has been made when launching a lifeboat. The results from the study provide a basis for improving the launch process. One important result was that lowering the launch position provides a significantly reduced risk of impacts against the mother ship. An idea of how to use this information to provide a calmer launching from high launching points has been numerically simulated. The models presented in this thesis are proven to be useful tools when investigating both conventional launching and innovative solutions of the launch process.