Dynamic Effects of Ship Passage on Moored Vessels

Abstract

A moored ship may experience strong disturbances even in a calm basin when other ships pass along at a sufficiently close range. These disturbances may be so strong in some instances that the sustained stress on the mooring lines might possibly exceed their breaking strength and result in breakage. The objective of this paper is to provide an engineering guide in estimating these loadings on moored ships, as this information should be of utmost value to harbor and ship engineers in securing berthing and mooring safety. The problem is investigated by using slender body theory approach. The effect of hydrodynamic interaction due to a steadily moving ship on a fixed vessel is derived. The resulting surge force, sway force and yaw moment acting on the moored ship are shown as a function of the passing-ship speed, the geometrical particulars of the two ships, their separation distance between ship centerlines, and the harbor water depth. Calculated results are presented graphically.