Abstract
In previous paper, the upper and lower bounds of hydrodynamic force acting on a body in an infinite fluid were discussed. In case where free surface exists, the hydrodynamic force can be made as the stationary value of the functional of the variational problems, but the upper and lower bounds of the hydrodynamic force can't be obtained, since the variational problems are not minimulm or maximum problems but stationary ones. The reciprocity and action theorems are obtained as in the previous paper. Interesting theorems such as Haskind theorem which give relationships between the scattering and radiation problems can be derived.
