Tanker casualties cause often serious environment pollution with disastrous effects. The important issue is to perform successful salvage operation and in order to do so, it is necessary to forecast the exact position of the disabled ship at each point of time. Programme of research was installed in the Ilawa Ship Handling Research and Training Centre (SHRT) with the aim to develop a computer code for prediction of the path of disabled tankers after casualty in various damage conditions, partially flooded or broken down in parts. Those are realistic situations that may happen after collision or serious damage to the hull as did show casualties of tankers ERICA or PRESTIGE. Mathematical model of ship drifting motion under the influence of wind, waves and sea current was developed that, requires, however, knowledge of force coefficients, in particular hydrodynamic and aerodynamic force coefficients for damaged ship. Model tests intended to estimate these coefficients were performed in the towing tank where the model was in different damaged conditions. Developed computer code is intended to be validated by tests of the large model in semi-natural scale in natural wind and waves on the lake. Suitable testing methodology and measuring system were developed and preliminary tests were performed in the lake Silm in SHRT where the model was drifting freely in intact condition or with partially flooded compartments, heavily trimmed to the bow
