An overview of squat measurements for container ships in restricted water

Squat is an important issue for ships navigating with limited under keel clearance in restricted waterways such as channels and canals. The admittance policy for containerships on the Western Scheldt, a tidal estuary in the Netherlands giving access to the port of Antwerp (Belgium), is based on a minimal static under keel clearance to ensure safe passages on the river. A large number of captive model tests executed in the Towing Tank for Manoeuvres in Shallow Water (co-operation Flanders Hydraulics Research – Ghent University) have been evaluated to determine squat prediction formulae. Measured sinkage and trim depend on a number of parameters like ship velocity components, ship loading condition, propeller action, blockage of the waterway, bank geometries and characteristics of other shipping traffic. The derived mathematical models have been implemented in the ship manoeuvring simulators of FHR to visualize the dynamic under keel clearance during real-time simulations at different locations on the Western Scheldt.Squat is an important issue for ships navigating with limited under keel clearance in restricted waterways such as channels and canals. The admittance policy for containerships on the Western Scheldt, a tidal estuary in the Netherlands giving access to the port of Antwerp (Belgium), is based on a minimal static under keel clearance to ensure safe passages on the river. A large number of captive model tests executed in the Towing Tank for Manoeuvres in Shallow Water (co-operation Flanders Hydraulics Research – Ghent University) have been evaluated to determine squat prediction formulae. Measured sinkage and trim depend on a number of parameters like ship velocity components, ship loading condition, propeller action, blockage of the waterway, bank geometries and characteristics of other shipping traffic. The derived mathematical models have been implemented in the ship manoeuvring simulators of FHR to visualize the dynamic under keel clearance during real-time simulations at different locations on the Western Scheldt.C