TPNA Tug SHASA getting a facelift in the Princess Elizabeth Graving Dock in the Port of East London.
Design of a new generation tug
June 10, 2019
Port Elizabeth, South Africa: Tug SHASA, the first tugboat delivered to Transnet National Ports Authority’s (TNPA) Port of Ngqura, has returned home after her fifth bi-annual service in the Princess Elizabeth Graving Dock in the Port of East London.
Delivered in 2009 from the shipyard in Durban, the 10-year old tug was the first of two 70-ton bollard pull Voith tugs to arrive in the Port of Ngqura, followed by the second tug named ORCA in 2010 and the third named LIZIBUKO, also in 2010.
This South African Maritime Safety Authority (SAMSA) regulated service is required every two years to ensure the vessel’s integrity. It entails the removal of old paint and the repainting of the vessel’s hull, the replacement of anodes which protect it against corrosion and a SAMSA inspection to ensure safe operations. Once qualified, the tug is issued with a 2-year dry-dock certificate.
“Basically it covers general maintenance of areas and equipment that are not easily accessible when the craft is in operation. It also covers the removal of rust and painting of areas such as the monkey island – the roof of the tug with radio aerials – inspection of the Voith system and blades which are normally under water,” said Xoliswa Bekiswa, Marine Operations Manager of the Port of Ngqura.
Design of a new generation tug
Durban naval architect Peter Volschenk was responsible for the design of this new generation of South African ship-handling tugs, working in close cooperation with the Marine Division of Transnet. In keeping with past practice, Transnet chose to stay loyal to the Voith Schneider propulsion system, used successfully in other South African ports.
SHASA has a 31m overall length, with a breadth of 11.5m and deep draft of 6.18m. A traditional round bilge tractor hull form has been adopted, with a large skeg and heavy fendering at the stern.
A pair of Voith 32R5/265-2 cycloidal propeller units is installed, each with five blades and a blade orbit of 3.2m in diameter. The units are powered by a pair of MAN 8L27/38 diesel main engines rated at 2,640kW, each at 800 rpm (total approximately 7,174 brake horsepower).
A bollard pull of 70 tons was specified for the first three tugs and 60 tons for the remaining quartet ordered for Transnet at the time. On trials SHASHA exceeded the predicted bollard pull with an exceptional figure of just over 80 tons.
Deck machinery includes a hydraulically powered Rolls-Royce – Brattvaag towing winch, a Palfinger PK12080 deck crane and a 3.8m Gemini rescue boat and davit. A single 480kg stockless anchor is handled by a windlass from Petrel Engineering.
SHASHA is equipped for firefighting to FiFi 1 standard, with two Counterfire water-foam monitors mounted aft of the wheelhouse. A pair of 1,200 cu/m/hr fire pumps are driven via Kumera ‘step-up’ gearboxes from the main engines.
Electrical power is generated by two Cummins 6B/BT5.9-D(M) 91 kW alternators, supplying the vessel’s systems via switchboards from Siemens.