NORWAY:

Double-acting ships make Arctic oil export routes competitive

As oil trade through the Bosporus reaches its practical limits, and flows from the Caspian region are increasing, Russia is seeking new outlets for its oil exports. New terminals are underway in Varandei in the North on the Pechora Sea coast and in Primorsk on the Carelian peninsula, as well as DeKastri in Sakhalin, all located in shallow waters and surrounded in winter by heavy ice fields. This carries high risks for oil pollution for conventional tankers and creates the need for expensive icebreaker assistance.

New technologies, like "double-acting" tankers and "oblique" multipurpose icebreakers, all developed by Finland’s Kvaerner Masa-Yards (KMY), now offer competitive new solutions. The first stage of the new Primorsk oil terminal is planned for 14-million t annual throughput, and ultimately 40 million t. Similar figures have been estimated for the planned Varandei and DeKastri terminals.

Illustration of new icebreaker in stern-first icebreaking mode.

Double-acting crude oil tanker. The first environmentally safe, double-acting crude oil tanker will enter service in 2002. Fortum Oil and Gas’ Shipping Division’s recently awarded contracts for two highly ice-strengthened, 106,000 tdw oil tankers from Sumitomo Heavy Industries of Japan meant a major breakthrough for KMY, Inc., and their patented concept for the double-acting ship. The two IASuper ice-class ships, to be delivered under a license from KMY, will be the first tankers to incorporate this new feature – which originally was developed as a cost-efficient solution to get oil from the Russian Arctic to world markets.

New electric-propeller drive system. In addition to regular ice expeditions to Arctic seas for refining the design, another important part of KMY’s work has been development of a new azimuthing electric-propulsion system. The first prototype, marketed by ABB under the Azipod brandname, was built and installed in 1990. The first full size unit, rated at 11.4 MW, was installed in 1993 on the Uikku, a 16,000-tdw Finnish tanker. This was followed two years later by a second unit on their sister ship, the Lunni. To date, these two ships have 55,000 hr of trouble-free operation using the system.

In 1997, the Uikku made maritime history as the first non-Russian merchant vessel to sail the entire Northeast Passage, taking only 12 days from Provideniya to Murmansk. One year later, the Uikku carried out an experimental midwinter demonstration voyage to the Gulf of Ob as part of the ARCDEV project, partly funded by the European Commission, and effectively showed that year-round navigation in Arctic waters is both technically and economically viable.

Double-acting ship. Combining advantages of electric propulsion with superb maneuverability, the podded drive provided designers with a totally new concept – the double-acting ship. Emergence of the pod drives changed many things. A fully rotating pod gives the designer a unique possibility to design the bow of the ship to be good in open water and allow the stern to break the ice. The result is a double-acting ship.

In a double-acting tanker (DAT) design, the mode of operation is completely different from normal penetration based on ramming. A DAT vessel enters a ridge field at slow or moderate speed, and lets its pulling propeller chew up the ridge and slowly pull the vessel through.

Less engine power, lower cost. The bow design of the DAT concept incorporates experience with conventional vessels, and is an efficient, ice-strengthened open-water bow. This gives open-water performance that is some 10% to15% better than that of a conventional ice-breaking bow. Utilizing the full potential of the bow-propeller effect, the vessel can attain the required icebreaking capability using only 40% to 60% of the power required by the best conventional icebreaking hull forms. In harsh environments, such savings may be critical for opening new fields. Ice-model tests with the Fortum 106,000 tdw tankers needed only 25% of the power used for similar performance by the 100,000 tdw test vessel T/T Manhattan, when sailing twice through the Northwest passage to Prudhoe Bay in 1969 and 1970. Flexibility of the machinery also offers several benefits.

In addition to the new Fortum tankers, KMY has signed a letter of intent with OAO Gazprom for construction of a 90,000 dwt DAT for servicing offshore fields in the Pechora Sea. This vessel is expected to enter Arctic service in 2005. A Norwegian patrol icebreaker for Spitzbergen, using the same pod arrangement, will enter service next year.

The first two icebreaking supply vessels for the Caspian Sea incorporating the double-acting concept were recently delivered by Kvaerner Masa-Yards’ Helsinki Shipyard, and have now passed their two-year guarantee period. Named Arcticaborg and Antarcticaborg, these two vessels work for the OKIOC consortium in the giant Kashagan field and feature twin propeller units totaling only 3 MW. This gives the master the capability of navigating in 1-m-thick ice in continuous mode, and of reaching a platform stern-first through bottom-fast ice formations around a drilling platform, a performance never experienced before in maritime history.

Oblique multipurpose vessels. The eastern end of the Gulf of Finland freezes every winter and is susceptible to heavy ice ridging. This represents a problem for wide-hull tankers. A tanker with a 40-m beam will always require assistance from at least two icebreakers, thus incurring high costs and long waiting times for other ships. The HELCOM maritime safety working group is already preparing for new regulations for compulsory escorting by tugs after they pass Hanko on Finland’s southern coast.

The cost-efficient solution developed by KMY is the asymmetric ship, better known as the "oblique icebreaker." Benefiting from the new podded drives and their ability to offer full power to any direction, this ship can easily break ice channels up to 40-m wide in 1-m-thick ice using only 3 x 3 MW of shaft, again something that has never before been possible in maritime history.

The oblique icebreaker, made possible through the use of three rotating propulsion units, combines compact size, low-power need and high-icebreaking performance for a wide channel. The unique hull shape offers large tank volumes, necessary for emergency response combating oil spills, while also allowing room for onboard installation of oil-spill equipment. This results in a multipurpose vessel that is small in size, low in price and replaces the need for separate icebreakers, escort tugboats and oil-pollution combating vessels. It is the ship of the future to secure safe passage of large tankers to and from the DeKastri, Primorsk or Varandei terminals.