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The South Korean-flagged tanker Southern Owl has passed her 5-year survey at Damen Shiprepair Vlissingen. With the work concluded satisfactorily, the ship now fully complies with the certification requirements of the NK classification society.
View of the intermediate propeller shaft in the engine room. The intermediate shaft is suspended so that the terminal shaft can be pulled in
“This Japanese-built ship arrived here on December 7th,” says Bas de Klerk, the DSV Project Manager who coordinated the work. “We carried out the job in our covered Dock 2. The 156 metre long and 25 metre wide vessel fitted easily as the dock is about thirty metres wide.”
The scope of the project included overhauling the overboard valves and extensive testing and inspection of the vessel’s PV valves. PV valves – or tank safety valves – regulate the pressure in a tank. These valves allow the tank to ‘breathe’ when the pressure changes inside. This prevents the tank from imploding or exploding.
The propeller intermediate shaft and terminal shaft were dissembled and inspected, enabling the play of the bearings to be measured and a number of seals to be replaced, adds Bas.
His team also checked the rudder clearance and replaced all the anodes. The anchor chains were also given the once over; they were laid out on the dock, measured, marked and then reinstalled.
“We replaced any piping that was in a bad state, and we cleaned and serviced the coolers. We also serviced the Southern Owl’s turbos and carried out an extensive painting programme,” says the Project Manager. “We polished the ship’s propeller, also carrying out non-destructive testing to detect any damage.”
Safety equipment on board the tanker, such as fire extinguishers and lifeboats, was inspected and replaced where necessary, although this part of the 5-year survey did not fall under DSV’s scope.
A challenging task was replacing the coupling bolts that connect the intermediate and terminal propeller shafts. “They had seized, so we removed them by machining and then we replaced them,” recalls Bas. On Saturday, December 19, the Southern Owl left DSV and headed to Antwerp, the work only taking a few days longer than the agreed period of ten days. This also called for work during the weekend. “A repair job like this – removing the seized coupling bolts – took a lot of time,” Bas notes. “We had to bring a kind of column drill on board to drill out the bolts.”
The Southern Owl at Damen Shiprepair Vlissingen
As mentioned, the aim of the entire project was to renew the Southern Owl’s certification. “The tanker now once again complies with all the requirements of the certification agency and we worked very well the ship-owner, Sansho Korea, to solve any problems that came up.”