  An alternative manner is provided for solving the classical linearised
problem of the radiation and diffraction of regular water waves caused by
oscillation of a floating body in deep water. It is shown that the singular
wave integrals of the three-dimensional free surface Green function $G$ and its
gradient $\nabla G$ can be regarded as regular wave integrals and are
integrated directly. The method is validated by comparing with benchmark data
for a floating or submerged body undergoing oscillatory wave motions. The
comparison shows that the evaluation is sufficiently accurate for practical
purposes. As the significance of the method, the numerical approximation
stability for the gradient $\nabla G$ is shown to be the same with that for
$G$.
