November 7, 2002

Double Acting Tanker in ice

Double Acting Tanker arrives in Baltic

The Azipod podded drive has been so widely adopted for recent cruise ship newbuildings that it's sometimes forgotten that it was first developed for icebreakers. The 105,000 dwt Japanese-built "double acting tanker" MT Tempera, which has just arrived in the Baltic, is the first cargo ship to exploit one particular advantage offered by the Azipod in ice conditons.

The Azipod was developed in the early 1990s by Kvaerner Masa-Yards in partnership with the Finnish Maritime Administration and ABB Industry of Finland, developed a new electrical propulsion system for icebreakers, the trade name of which is Azipod. The first vessels equipped with the new system, the 16,000 dwt tankers M/T Uikku and M/T Lunni owned by Fortum operated Nemarc Shipping, have now, combined, nearly 100,000 hours of operation experience. The vessels have several times successfully navigated through the Northeast Passage in extremely harsh conditions.

Since then, the Azipod propulsion system has been installed on the Finnish icebreaker Botnica, the icebreaker Svalbard, recently built for the Norwegian Spitzbergen, two icebreakers built by Masa-Yards for the Caspian Sea as well as the icebreaker Mackinaw, under construction for the Great Lakes of the United States.

Systematic R&D by Kvaerner Masa-Yards, and the experience accumulated with Uikku and Lunni, have shown that vessels with a podded drive are capable of breaking ice with a considerably higher efficiency than before, when moving backwards with the propeller first. Based on this observation, a new type of a combination was developed in which the vessel travels back to front in the most difficult ice conditions; at the same time, the design of the bow can be optimized for navigation in open water.

This concept developed by Kvaerner Masa-Yards, which has been granted a patent in several countries, enables a considerably better operating economy than before on vessels intended for winter traffic, and allows a vessel to obtain a higher ice class with a machinery power that is considerably lower than before.

The 105,000 dwt M/T Tempera, built in Japan for Fortum Shipping, which has now arrived to its home waters for the first time, as well as M/T Mastera that will be completed later, are the first cargo ships of this double-acting type in the world. In open water, they can reach a speed of 17 knots, and thanks to their efficient icebreaking capacity that can be achieved while running with stern first, they are entitled to the highest IA Super Ice Class with their engine power of 16 MW. Using conventional technology they would require as much as 25 MW. These vessels are able to navigate independently in the Baltic Sea area.

"The benefits of this concept have been recognized by the shipping companies, and we actively seek new applications of it, not only on icebreakers but also on ice-strengthened tankers and cargo ships, in particular in connection with the new oil production projects of the Pechora Sea and Sakhalin", says Jorma Eloranta, President and CEO of Kvaerner Masa-Yards.

M/T Tempera was built at the Yokosuka shipyard of Sumitomo Heavy Industries Ltd in close co-operation with Kvaerner Masa-Yards under license by the latter company. The Finnish shipbuilding group has been engaged in cooperation related to product technology with SHI since the mid-1980s.

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