Stability and Upsetting of Small High-Speed Boat

点击翻译按钮获取中文摘要

The stability and the upsetting of a small high-speed boat were investigated, and the main results obtained are as follows;(1) The aerodynamic characteristics of the boat were studied in a wind tunnel. Sometimes, the upsetting moment caused by aerodynamic lift becomes very large if the boat jumps from the water surface.(2) The hydrodynamic forces and moment acting on the boat hull were measured in the various running conditions. From the experiments, it was found the boat is generally stable in the still water.(3) The flow phenomena in the boat bottom and the wetted surface area were observed with a transparent plastic model and it was found, the surface tension gives the important effects on the flow phenomena of small model.(4) A simulation study of maneuvering motion is attempted by formulating the equations of motion. This simulation available to solve specific problems.(5) The process of upsetting are, (i) the boat begins to jump caused by some disturbances on the free surface, (ii) during the jumping, the boat changes its trim and heel and the hull reseives comparatively large aerodynamic lift and moment, (iii) leaving the water surface, there is no stabilizing hydrodynamic force, then the boat goes to upset.