30 cm extra draft for outgoing vessels

The Port of Rotterdam started a pilot on maximizing the draft for outgoing tankers. Before this pilot, the operational maximum permitted draft for ships leaving port was 21.5 m.

Charta Software performed a study to determine the possible maximum draft from three different berths. Without investments in the infrastructure, but by using available data and advanced modeling, we showed that it is possible to safely increase draft by 30 cm up to 50 cm for, respectively, 99% to 98% of the time. Based on this study the Port of Rotterdam started a pilot to test this operationally.

We imported two years of environmental data (water levels, currents and waves), together with the channel bathymetry and design, to model the port and routes in PROTIDE. All outgoing tankers in this period were investigated on reported dimensions/draft and AIS data.

With this data we determined which channel segments are relevant and what speeds are possible in the given circumstances. For each high tide in the analysis a maximum draft calculation was made for an outgoing transit where the under keel clearance remained safe. In this calculation PROTIDE determines the static under keel clearance based on tides and available depth; the dynamic under keel clearance results from a squat calculation and calculated wave response.

The study was finished with a sensitivity analysis on operational requirements, speed, salinity, channel shoaling and the maximum draft to remain at berth. Europoort Kringen published an article on this project in their June 2020 magazine.