Construction of two icebreaking crude oil carriers is underway in Yokosuka, Japan, based on the double-acting technology (DAT) used during the construction of the icebreaking supply ship, Arcticaborg, now operating in the Caspian Sea.
Kværner Masa-Yards' double-acting Arctic tanker (DAT) design concept has received a breakthrough. A contract has been received from Fortum Shipping. The contract, signed in Helsinki last year, is for two icebreaking 106,000 dwt crude oil carriers to be constructed at the Japanese Sumitomo Heavy Industries yard in Yokosuka.
This will be the first use of DAT icebreaking technology on newbuild tankers. DAT was patented by Kværner Masa-Yards' Technology Centre (MARC) and adapted for the two icebreaking supply vessels the company built for the Royal Wagenborg Group in 1998. MARC, based in Helsinki, performs product development, design and testing of icebreaker vessels and structures operating in ice or severe cold conditions.
For the Fortum crude oil tankers, MARC and Sumitomo have been working under a mutual cooperation agreement to develop the project to meet all the requirements set by Fortum Shipping. This cooperation agreement has been extended to continue through the construction phase of the tankers and will enable both companies to offer vessels based on the DAT concept to other clients.
"The Forum vessels will be completed in the summer of 2002," says Kværner Masa-Yards director Mikko Niini, "and we are already receiving considerable interest from other companies in the DAT concept. These particular vessels will be based in the Baltic Sea, but the design means they are capable of operating in even more extreme climatic conditions, such as the Barents Sea."
Ice routes tankering
The DAT concept is made possible through the use of Azipod propulsion mounted on the bow of the vessel.
Double-acting technology is the result of extensive research and development work carried out by MARC during the 1990s, which actively seeks to create innovative and cost-efficient technical solutions for marine operations in ice-laden waters. Wide-ranging ice model tests have been conducted and expeditions have collected real field data on ice conditions in potential northern sea routes such as the Pechora Sea, Sea of Okhotsk and the Baltic. The experiments on the Nemarc (a joint-venture between Fortum and Kværner Masa-Yards) tankers M/T Uikku and Lunni during operation through the Russian Northern Sea Route (North-East passage) were an important step in further developing the concept, which originally surfaced in the early 1990s.
The double-acting concept is based on the idea that the stern of the vessel is designed to break the ice in heavy ice conditions. This is made possible by taking full advantage of the possibilities offered by Azipod electrical podded propulsion systems. When the ship is running astern, the Azipod propellers create a strong lubricating water stream against the hull and thus reduce the friction. In this mode, the tankers will have sufficient icebreaking capabilities using only 60-70% of the power required by conventional ice breakers. Cost savings can therefore be realized as less engine power is needed.
Apart from the continuing development of its DAT technology, MARC is currently active in looking at further ice technology issues specific to the Arctic, Sakhalin and Caspian regions. According to Niini, Kværner Masa-Yards is also looking at further opportunities for constructing floating production units in cooperation with its sister company, Kværner Oil & Gas, following the completion of the Esso Jotun FPSU (floating production and storage unit) at its Truku yard in 1998. Although no firm orders are yet on the table, Niini says that the two companies are actively looking at possibilities in West Africa.
