An extensive maintenance dredging campaign is under way at South Africa’s Port of Mossel Bay in anticipation of an increased volume of shipping serving the offshore oil and gas exploration sector.
In February 2019, global energy giant Total announced a gas-condensate find with a potential yield of up to one billion barrels in its Brulpadda (Afrikaans for bullfrog) deep-water field, 175 km southeast of the port.
“The platform supply vessels [PSVs] used by Total require a specific under-keel clearance. That clearance should be sufficient to allow ship’s floatability in most unfavourable hydrological and meteorological conditions,” said Shadrack Tshikalange, Port of Mossel Bay’s port manager.
“Therefore, the quaysides that will be used by the PSVs must be dredged to their maximum depth to allow berthing of such vessels in any condition.”
Currently, the harbour entrance channel has a depth of 8 m, while inside the harbour the maximum permissible draught is 6.5 m.
Two dredgers have been assigned to the port, the 4,500 m3 grab hopper Italeni, which arrived in November, and Isandlwana, a trailing suction hopper dredger (TSHD), which will arrive in January 2020.
Italeni will work on the quaysides, which haven’t been dredged in 20 years, while Isandlwana will focus on the entrance channel, sand trap, and the turning basin of the port.
The two dredgers complement each other in that the TSHD is built for high-speed sailing to the offshore disposal site while the smaller Italeni improves the accuracy of the final dredged depths.
Transnet National Ports Authority fleet renewal programme has boosted its dredging division’s capacity to aid the removal of about 4,000,000 m3 of excess material from the seabed every year at South Africa’s ports.
With the most modern equipment available in the specialised service industry, dredging services can not only meet the needs of the South African port system, but the needs of southern Africa, helping other African countries to grow their economies.