The world's strongest: Umiak I
Article paru dans : DNV Bulk Carrier Update
Umiak I is a 31,992 tonne icebreaking bulk carrier, the most powerful ever of its kind. The vessel moves 360,000 tonnes of nickel concentrates a year in 12 voyages from CVRD/lnco Ltd/s Voisey's Bay mine in the northern Labrador to its smelters in Sudbury, Ontario and Thompson, Manitoba, Canada.
The DNV-classed vessel has ICE-15 class notation, one of the highest ICE notations any vessel can have. Basically, this means the hull is reinforced to navigate un-assist-ed through ice that is 1.5 metres thick. This very powerful and unique bulk carrier only uses 35 per cent of the available engine power on the open, ice-free sea.
"Umiak I is a very specialised vessel carrying an expensive cargo. Just the four-cargoes we move during the winter season have a value of more than one billion dollars -just look at the London Exchange for global nickel prices," says Thomas H. Paterson, vice president of the owned fleet and business development at Fednav. He is joined by John Weale, Vice-President, Risk Management and John T. Stubbs, manager, technical services, projects and business development.
"Nickel carrier Umiak I beats the big-freeze" is the headline in a Fednav press release:
"Built to serve a long-term contract covering- the transportation of nickel concentrates from northern Labrador to St Lawrence river, the vessel is testament to Fednav group's long standing expertise on providing solutions to challenging bulk cargo logistics. The concentrates shipped by Umiak I derive from CVRD/lnco's new Canadian $ 3 billion Voisey's Bay Nickel Company mining, processing and production facilities. Cargoes are shipped out of Edward's Cove for the 1,100 nautical mile passage to Quebec City from where transshipment is made to rail for deliveries to smelters in Ontario and Manitoba.
Managed and operated by Canship Ugland of St John's, the ship is designed not only to carry bulk concentrates, but also re-supply cargoes for the production operations, including fuel oil. Although Voisey's Bay is located just south of the 60th N parallel, outside the Arctic Circle, winter ice conditions are more demanding than those in many high Arctic areas.
On her regular run down the Labrador coast, Umiak I contends with some of the world's most rugged ice conditions, including icebergs, from November to July each year.
The 90-kilometre channel to the Edward's Cove loading- terminal passes through a maze of islands, and has a five-month 'open' season. In addition to the subsequent ice build-up seawards, ice originating further north is driven southward by the Labrador current, creating particular challenges in navigating though hard-packed shear ice."
"When the vessel encounters ice conditions and eventually stops in the thick ice,' says Paterson, "it backs up before ramming the ice. The only way to get through is by using brute force. In order to do this the vessel has provided a milestone reference, an electronically controlled MAN 7S70ME-C engine producing 21,770 kW on a driving controllable pitch propeller," he says.
Fednav adopted the vessel to the demanding and mixed operating profile. This calls for a broad range of operating modes, including ice ramming, slow steaming and open-water service entailing both high and low load scenarios. The electronically controlled engine offers the requisite degree of flexibility with good operating economy, and reduced emissions in an ecologically sensitive area.
Capability for effective ice ramming goes hand-in-hand with the ICE-15 classification. The ramming procedure entails sailing at a specified speed through the ice until the vessel is brought to a stop by the resistance of the ice. The vessel is then put astern so as to come free of the packed ice, and is then sailed full ahead, to break through the ice until brought up again by the force of resistance. The procedure is used for thick ice and ice ridges, and imposes exceptional demands on the main engine. In order to enable repeated ahead and astern working within a short time-cycle, Umiak I has been equipped with a controllable pitch propeller, obviating the need for the time-consuming task of reversing the engine. The screw is enclosed in a nozzle to protect the propeller against blocks of ice and to confer extra trust.
"While the open-water speed in a laden condition is some 13.5 knots, the bulk carrier is said to be capable of making three knots in level first-year ice of 1.5 metre thickness," the company states in a press release. The vessel has an ice breaking-bow, a wash system to help reduce friction in ice, a V-shaped stern and an ice knife to protect the rudder. The vessel was constructed at Universal Shipbuilding's Maizuru yard, Japan.
Navigation in the waters north of the 60th parallel is a challenge with ever-changing ice conditions. Umiak I uses the Enfotec IceNav system—Fednav has provided the developmental platform. IceNav is a shipboard navigational software package.
The main constituents of the system—as demonstrated to us by Robert Gorman, Manager Environmental Services, Enfotec—are the IceNav Navigation Module and the marine Radar Module, operating on a single PC with displays on two screens. The two modules are completely integrated with route plans created on one module and displayed on the other. In addition, the more recently developed component of the Marine Radar Module is the IceNav Hazard Detection Module, designed for ships that routinely navigate in high concentrations of first-year ice where old ice and embedded icebergs and 'berg)- bits' are a hazard. Fednav's new addition has been designed with the flexibility to offer competitive use in general international bulk trade, notwithstanding-special ice-going capabilities.