The initial research on air flows dynamic impact on a ship model of 888 project type

During operation, a ship is open to dynamic effects resulting from specifics of marine environment. Among these effects, wind dynamic impact together with a wavy motion is especially hazardous for the ship. These impacts generate heels to the big angle. The angle of dynamic heel can be determined according to IMO regulation but the real value is different. Determination of a real value of the dynamic angle of heel is possible by executing model tests performed with geometric and dynamic similarity scale taken into consideration. Results of initial research on air flow's dynamic impact on a ship model are presented in the elaboration. The research has been executed at a test stand located in the Polish Naval Academy. Main elements of the stand consist of model basin, ship model of 888 and 660 project type, computer registering parameters of the ship model position, device generating air flow. The ship model of888 project type has been an object of the tests. It was made in a scale 1:50 in respect to a real vessel. Results of executed measurements have been compared with theoretical calculations for an angle of dynamic heel. Input parameters for the tests and calculations have been defined in accordance with recommendations of Polish Register of Shipping (PRS) and IMO [1, 2, 5]. Determination of a heeling moment by wind operation has been a key issue. The executed research has revealed that the way the criteria of the ship's dynamic stability are defined by PRS and IMO takes a certain safety margin into account.