Abstract: A method is developed in which the time-stepping algorithm and the boundary integral equation method are employed to calculate vertical and oblique water entry of a blunt cylinder, which is a 3-d, nonsteady, incompressible and inviscid fluid flow problem with nonlinear free surface and fluid-body interaction. The free surface is described in terms of La-grangian coordinates and the body surface is described in terms of Eulerian coordinates fixed in the body. Implicit schemes of second-order precision time-d...