Port Otago's new $8 million backhoe dredge Takutai was gingerly lifted off its delivery ship on Wednesday in a more than four-hour, slow-motion operation.
The specialist 143 metre heavy lift ship Fairpartner from the Netherlands remained entirely afloat during the unloading at Port Chalmers, unlike larger vessels of its type, it did not flood its hold and partially submerge for the cargo to float off.
Port Otago's marine and infrastructure general manager Sean Bolt said the Fairpartner instead uses a complex, computer-controlled water ballasting system, which works in conjunction with the speed of its cranes, to counter-balance the lifting process. The 35m Takutai weighs about 650 tonnes.
“It's simply the lift of the two cranes,” Bolt said.
Just after 4 pm on Wednesday the Takutai's hull safely touched down on the water after about three hours of gentle manoeuvring, and yesterday its three legs, weighing more than 100t combined, would be offloaded.
The Takutai is set to replace the bucket dredge Vulcan, whose hull is understood to be 100-years-old, and will be used for all facets of upper and lower harbour channel work, with a 19m bucket reach.
While having no propulsion of its own, the Takutai has three 13m high legs which once on the seabed can otherwise “crab” its way across the seafloor, loading the barge Hapuka, with spoil, for under towing by the small tug Arihi.
Once training had been completed for Takutai's two-person crews, it is expected to be at work by mid-next month. Built for one specialist project in France in 2012, the renamed Takutai was required for only one year's work and is expected to have a 30-year lifespan ahead with Port Otago. Its $8 M cost included delivery charges.
*Simon Hartley is senior business reporter and assistant chief reporter for the Otago Daily Times.