The half angle subtended by the wake of a ship in deep water is shown to be the arcsin(1/3) or approximately 19.47 degrees. The approach uses the fact the phase velocity of water waves is twice the group velocity in deep water. The method employed does not address ship speed, changes in ship heading, length of ship, etc. The case of shallow water is briefly addressed and the half angle wake angle for the shallow water case is suggested to approach approximately 90 degrees. Andrew R. Ochadlick Jr. received a Ph.D. in Physics from the State University of New York at Albany (SUNYA) and is a career physicist with university, government and industry R&D experience and teaching experience at the undergraduate and graduate level. He may be reached at [email protected] .
