This article presents
an algorithm for intersecting an arbitrary mesh with the surface of water and for calculating the hydrostatic forces acting on the body described by that mesh. If you were to write a program which does only that, you would get a boat oscillating up and down as if it were on a spring. The boat will be pushed out of the water into the air, then fall because of gravity, dive back in and be pushed out again into the air. What is needed to stabilize the system is damping. The hydrodynamic forces which are the subject of the next article are very effective at damping the system, as they are in reality. But it is possible to cheat and just apply heavy speed based damping in all directions of motion, or especially in the vertical dimension, to get a sense of what you get with the hydrostatic forces as calculated with the algorithm we just described.