Feature 5 | RUSSIAN MARINE INDUSTRIES
In action, Mikhail Ulyanov dispays its ice breaking capability.
platform Direct Oil Offloading Complex (DOOC). The 10,000m3
/h capacity
Maritime Pusnes AS system is fully compatible with all other offshore loading facilities requiring “North Sea Type” bow loading. To meet their exacting tasks, the hull
form for the Prirazlomnoye tankers was developed by Aker Arctic Technology Inc. (AARC), based on the double acting operation principle, for year round independent navigation in seasonal “average” ice conditions. Pioneered by Aker Arctic Technology,
the double acting concept found first form in the shape of the tankers Mastera and Tempera, delivered by Sumitomo Heavy Industries to Neste Shipping. Sovcomflot, meanwhile, already has three Aker Arctic- designed double acting tankers in service delivered by Samsung Heavy Industries, while Norilsk Nickel is operating the first five double acting containerships ever to be built, and is in the process of taking on a sixth double acting ship, this time a product tanker from Nordic yards of Germany. Mikko Niini, president of Aker Arctic Technology Inc., said: “For the
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Prirazlomnoye shuttle tankers, the hull form has been optimised for two modes of operation in first-year ice conditions. Tose are astern operation in medium and thick first-year ice and ahead operation in thin and young ice conditions and open water. “A double acting ship draws on operating
experience and knowledge of the improved ice going performance of existing icebreakers arranged with bow propellers. The two basic hull-ice interaction mechanisms for improved ice going performance are decreased hull ice resistance, due to ‘washing’, or ‘lubrication’, of the hull by the wake of the bow propeller, and improved hull icebreaking performance, due to the slight pressure drop that occurs just ahead of the icebreaker due to water flow into the bow propeller.” Dimensioning of hull structures for ice
strengthening for the ships is in accordance with Russian Maritime Register of Shipping ice category LU6 (Arc 6) , with the stern of the vessel strengthened for bow design ice loads for double acting operation. The shuttle tankers are dual classed by RMRS and Lloyd’s Register, with a class notation of KM * Arc6 [2] AUT1 EPP Oil
Tanker (ESP). Here, the shell in the forward region
of hull ice strengthening is transversely framed throughout; with built section main and intermediate ice frames at 400mm spacing. A 60mm thickness stem bar is arranged with a 45mm radius stem plate. The bottom shell in the forward
intermediate region of ice strengthening is longitudinally framed. At the edge of each of the vertical regions on the ship side there is a 4mm step down in shell plating thickness. Te side shell in the midship region ice
belt between the ice load waterline and ballast waterline is strengthened with bulb sections for the main and intermediate ice frames at 400mm spacing. Within the double side skin space there are platforms decks arranged vertically every 3.4m with intermediate ice stringers. Te underwater hull form incorporates
an icebreaking bow for operation ahead in young ice and thin first year ice conditions. However, as the tanker has also been designed for international trade, the bow shape is derived from a compromise between performance in ice and open
The Naval Architect July/August 2010
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