ICCE 2022

How to Cite

MOORED SHIP MOTION FORECAST TOOL FOR THE PORT OF NGQURA. (2023). Coastal Engineering Proceedings, 37, structures.67.


Significant future growth is planned for the Port of Ngqura, but the Port does, however, suffer problems with moored container vessels. Under certain environmental conditions, these moored vessels experienced large motions, which lead to reduced operability or downtime and sometimes mooring line failures. One of the main contributing factors to the mooring problems is infra-gravity or long-waves (i.e. wave periods between approximately 25 s and 300 s), which induce basin and moored vessel resonance. A long-wave forecast system has been developed to assist the Port. Although this forecast system is accurate in predicting long-wave heights inside the Port, it does not give the port operators a full picture of the effects on moored vessels due to the complex nature of the interaction between these waves and the moored vessels. The long-wave forecasts alone are therefore difficult to interpret if the port operators do not have a background in vessel dynamics. A new tool, in the form of a moored vessel motion prediction system, was therefore developed.


Reniers, Roelvink, Dongeren (2001): Morphodynamic response to wave group forcing, in Coastal Engineering 2000. pp. 3218–3228.

Reniers, Roelvink, Thornton (2004): Morphodynamic modeling of an embayed beach under wave group forcing. Journal of Geophysical Research: Oceans 109.

Troch, Terblanche, Rossouw, Ntantala, Du Plessis (2020). Long-wave mitigation study for the Port of Ngqura. Coastal Engineering Proceedings. 28.

Van der Molen (2003): Long-period wave forces on a moored ship in a harbour using a strip theory approach, in: Proc. 2nd Int. Conf. on Port and Maritime R&D and Technology (Singapore), 2003. pp. 113–120.

Van Der Molen, Monardez, Van Dongeren (2006): Numerical simulation of long-period waves and ship motions in Tomakomai Port, Japan. Coastal engineering journal 48, 59–79.

Van der Molen, Rossouw, Phelp, Tulsi, Terblanche (2010): Innovative technologies to accurately model waves and moored ship motions.

Van der Molen, Scott, Taylor, Elliott (2016): Improvement of mooring configurations in Geraldton Harbour. Journal of Marine Science and Engineering 4, 3.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Copyright (c) 2023 Chris Troch, Luther Terblanche, Marius Rossouw