Published online by Cambridge University Press: 20 April 2006
In studying head-sea diffraction by a slender body, Haren & Mei (1981) found, at a special frequency, a singularity inherent in the cross-section (inner) mathematical problem. In this note this singularity is interpreted, and it is shown that the head-sea problem is similar to the problem of an acoustic duct being excited at one end by a pressure field. As a consequence, the head sea is not always refracted away from the body, since the solution remains oscillatory for frequencies above that special frequency.