Vessel navigation risk and stern-swing index in sharp bend channels

Abstract

Owing to the drastic change in flow conditions and river boundary of sharp bend channels, marine accidents occur frequently. A typical sharp bend channel was selected, whose flow velocity and navigation were studied by using a scaled hydrodynamic model and scaled vessel model maneuvering test. Based on the vessel speed, drift angle, and transverse flow velocity, the stern-swing index Δ was deduced, and a navigation risk model was established, which showed different navigation status and corresponding ranges of Δ. Transverse flow velocity is usually larger at the impact point of current on the river bank. The impact point moves downstream when flow rate increases. The hull undergoes swing, rotation, and drift under the combined action of current force and rudder force, the resultant moment caused by these two forces was represented by Δ. When the absolute value of Δ is in the range of 0–1.2, it can be used to judge the risk of a vessel passing through the sharp bend channel.