This paper presents the second-order diffraction problem for a large vertic
al cylinder. Expressions have been obtained for three second-order forces,
namely waterline force, dynamic force, and quadratic force. The first-order
potentials contribute to waterline and dynamic forces, whereas the second-
order potentials contribute to the quadratic force. This quadratic force is
obtained with the knowledge of the linear diffraction potential only using
the Green's function method; an explicit form of the quadratic potential i
s not needed. The theory in this paper emphasizes on the contribution of th
e second-order forces to the total force. (C) 1998 Elsevier Science Ltd. Al
l rights reserved.