The Port of Durban, catering for all cargo sectors and especially containers, automotive and bulk liquids, continues with its infrastructure investment programme in order to meet the needs of shippers and the South African industries they serve. Dave Ward, project manager for Transnet National Ports Authority (TNPA), told John O’Hanlon how the Durban Harbour Entrance Widening & Deepening (DHEW) project is taking the port into the era of the big ships.
Durban has one of those magnificent natural harbours that must have seemed a godsend to early navigators. The haven is guarded by a bluff that reaches up like a finger and the southern breakwater is actually further north than its opposing northern counterpart. Shipping approaches the harbour from the north, and the primary reason for widening and deepening the entrance channel was to improve the safety of navigation of vessels into and out of the port in line with international standards.
From the port users’ point of view the channel is now more accessible in all states of weather. When it was narrower and shallower the Port experienced occasional downtime due to weather conditions. With it now widened and deepened, the Port has now reduced disruption of that sort. There were restrictions on the larger vessels, and those restrictions have now been removed.
However, there’s a more important strategic reason behind the R3.9 billion investment. The largest ships that could be handled prior to 2007 were 4,000 TEU (20 foot equivalent unit—the standard measure for container ships). The original design increased that to 6,600 TEU, but Korea’s Samsung, a shipyard that has led the development of large container ships, had started to build 9,200 TEU vessels. As that was clearly the way the market was going, the design was changed to accommodate these ‘post-Panamax’ behemoths. The revised design specification will give Durban a distinct competitive edge over other ports and enable it to accommodate the larger container vessels—which deliver lower freight costs to shippers and industrial end-users alike but so far do not call at African ports.
The project was an opportunity to clear out a number of hazards from the harbour, including four concrete caissons deliberately positioned to prevent U-boats from slipping in during World War II. These had to be removed ahead of the dredging operation, and the original plan was to lift them intact and dump them out to sea, says project manager Dave Ward. “Achieving this was quite challenging because the structural integrity of these caissons had deteriorated with the result that we could only do that in sections. We did manage to float one caisson out, but the rest we had to cut up into much smaller pieces using advanced technologies such as underwater diamond saws.”
Another surprise that turned up well into the contract was the discovery of an unknown wreck in the channel for which historical records were unavailable. “The approach to the identification of the wreck and rendering it harmless to shipping while meeting the objectives of the project was in itself a significant achievement,” says Ward, who emphasises that the speed and efficiency with which this project was brought to completion in February 2010, a month ahead of schedule, can be attributed mainly to good communication between the Port authorities, the shipping lines and the contractors and subcontractors. “We were able to execute some of the dredging work ahead of time, even in the navigable channels, without disruption to shipping and the working Port. It was business as usual.”
With around 8,000 ships utilising the harbour every year that was quite an achievement, he adds. “Throughout the project we were able to keep the traffic going in the Port by doing all the work on the north side first, then diverting all the traffic into the channel on the north while we then turned our attention to the south channel. That proved to be very successful.”
In February 2003, coastal engineering consultants Prestedge Retief Dresner Wijnberg were appointed jointly with the CSIR Stellenbosch to undertake the preliminary design work. The main contract for the works was awarded in May 2007 to a consortium comprising Dredging International of Belgium and Group Five of South Africa, while project management was carried out by Transnet Capital Projects and its joint venture EPCM (engineering, procurement and construction management) contractor HMG (Hatch, Mott MacDonald, Goba).
The type of contract used was the New Engineering Contract (NEC), and Ward believes this was a key factor in managing risk and controlling the project, thereby overcoming potential problems. “The NEC form of contract is based on mutual trust and cooperation between contractor and client. This assisted all stakeholders to focus on project objectives and find solutions.”
Safety is always a good indicator of how well a project is being approached, and the project achieved one million hours without an LTA (lost time accident). “Health and safety were constantly enforced,” Ward says. However, the outstanding safety record also depended on the quality of collaboration between the contractors and project management teams, and their experience. “We were pleased that even the newer but more innovative subcontractors found in the project an excellent opportunity to stretch their capability in partnership with a global player like Dredging International. This assists in demonstrating the expertise available in South Africa and is good for the construction industry. An example of this is the Durban-based commercial diving and marine construction company Subtech, for whom this was a significant contract where they were responsible for the numerous underwater tasks prior to and during the contract, including such work related to the removal of an old service tunnel under the harbour.”
No two marine projects are the same and what makes Durban unique, says Ward, is the geographical position of the Bluff headland and its extension to the South Break Water. This is a great asset to the Port in creating natural protection to the harbour and was thus not suitable for widening the channel to the south side. “In the event we decided to do all our widening and deepening on the north side. Apart from strengthening and raising the southern breakwater by two metres, we left other structural aspects of the South Break Water unchanged.”
The successful delivery of the DHEW highlights the need for deeper berths to realise full value in the Port. Various developments are underway to deepen berths in the Port to ensure that vessels meeting the design capacity of the entrance channel may be serviced. Several feasibility studies in this regard are underway while the reconstruction of some berths has commenced. http://www.transnetnationalportsauthority.net/
