The challenge

A Ghanaian oil and gas company plans to build a large breakwater and mooring constructions in the Gulf of Guinea in 2017-2018. The port is necessary for better distribution of crude oil to a new oil terminal on the mainland. The breakwater has a planned length of more than 1.5 kilometres. The current port facilities in the area around Accra are not sufficient for a quick throughput and distribution of oil and petroleum products. Among other issues, the port is not accessible for large oil tankers and the SPM mooring systems are outdated, causing long waiting times. The rising costs of the delays are causing annually the loss of millions of dollars in sales and profit.

Our contribution

Walhout Civil has been contracted for the preparation, the preliminary design and engineering of the breakwater and moorings systems from 2016. The designed 20-meter high breakwater consisting of rocks and heavy concrete elements, needs to protect the port facilities for strong currents along the Ghanaian coast and the impact of breaking offshore waves. Ingenious solutions are needed for the mooring of the oil tankers and the manoeuvrability impact of multiple vessels in shallow waters. Especially the foundation of constructions on the hard, deep seabed is a major challenge. The presented design focuses on a multifunctional usability of the port and the return on investment within the supply chain. A summary of our activities in the preliminary design study:

  • Metocean study and data collection;
  • Quick scan and analyses of waves, currents and morphology;
  • Design of access lanes, manoeuvring and anchor areas;
  • Design of offshore breakwater construction, quays and port facilities;
  • Management summary for future dredging activities and port maintenance.