Norshipco Completes Work On Double-Hull Tanker Stena Concertina Acquire Air & Water Technologies Unit

The double-hull designed oil tanker of the future, mandated by Congress as a safeguard against disastrous oil spills, is making its presence felt in American waters. Norfolk Shipbuilding and Drydock Corp. (Norshipco) completed a contract to drydock and repair the Japanese- operated Stena Concertina, a two-and-a-half year old crude-oil tanker equipped with the latest in marine technology.

The yard work consisted of blasting and coating, tailshaft and rudder clearance inspections, valve, pump and generator repairs, and miscellaneous planned maintenance of and inspections to the main engine. Other jobs entailed pipe repairs, windlass inspections, and miscellaneous gas-freeing.

Norshipco's contract also included warranty work in coordination with the builder, Sumitomo Heavy Industries of Japan. Norshipco's largest task was in the area of shell-plate repairs. The ship had run aground off Corpus Christi, Texas only three months after being launched, and was sailing with a deferment on replacing damaged steel in the areas of the forward peak tank and No. 1 double bottom tank. The initial work package was to replace 35 tons of steel in 14 days, but by the time the ship arrived, the steel-work time frame had been reduced to only eight days, while the overall scope of the steel job grew to 50 tons as the job unfolded. Norshipco actually completed all shipfitting and welding in seven days.

The Stena Concertina is the prototype of a new class of tanker commissioned by the Japanese shipping conglomerate Mitsui O.S.K. Lines, Ltd. Stena Concertina is the first ship commissioned by Mitsui to incorporate the advanced double-hull design.

The Stena Concertina normally operates on the Gulf of Mexico traderoutes as a lightering ship, off-loading crude oil from larger tankers that are anchored off-shore. The vessel displaces 94,000 dwt, is 761 ft. (232 m) long with a beam of 138 ft.

(42 m) and has a single 12,070 hp diesel engine with a cruising speed of 15 knots.

For more information on Norshipco, contact the company at P.O. Box 2100, Norfolk, Va. 23501- 2100, tel: (804) 494-4000; fax: (804) 545-0604.