NASSCO Building 188,500-DWT Tankers For Alaskan Oil Trade

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tankers for alaskan oil trade

The first of two 188,500-deadweight- ton San Diego-Class tankers for long-term use by Shell Oil Company was floated out of the graving dock of National Steel and Shipbuilding Company (NASSCO), San Diego, Calif., on July 21, 1977.

The two new ships, the largest ever built on the West Coast, represent the first flight of San Diego-Class tankers to be designed and built by NASSCO.

Completion work on the floated tanker, designated as Hull No. 405, will continue with delivery and christening scheduled for late 1977 or early 1978. The second ship is scheduled for delivery in the third quarter of 1978. Each tanker will have a crude oil cargo capacity of about 188,000 long tons (about 1.3 million barrels), and will be chartered to Shell Oil Company of Houston, Texas, for anticipated long-term service in the transportation of crude oil from Alaska to mainland United States ports.

The two ships will be 951 feet in length, 166 feet in beam, 78 feet molded depth and will have a loaded draft of about 59 feet. Propulsion is by a twin boiler geared steam turbine plant which is capable of being operated continuously at 28,000 shaft horsepower.

Engine speed and direction can be controlled from a console on the bridge.

The ships include the latest environmental features. They have full double bottoms and sufficient clean segregated ballast to comply with U.S. Coast Guard and proposed IMCO "International" Rules for Prevention of Pollution of the Sea by Oil. Current rules of the Environmental Protection Agency for no overboard discharge of sewage are met by full onboard retention in holding tanks. The vessels are also fitted with a collision avoidance radar system.

An inert gas system, designed to fill the void spaces in the cargo tanks, thereby minimizing the possibility of an explosive vapor mixture, has been fitted. The cargo system is designed with a holding tank to collect oil from tank washings for discharging to shore facilities. The bilge system contains apparatus to effectively separate and retain oil from the bilge waters for discharge to shore in accordance with the U.S. Coast Guard requirement.

Other NASSCO-designed tankers under construction are on order for the Alaskan oil trade and include two 188,500-dwt San Diego-Class tankers for Atlantic Richfield Company and three 90,- 000-dwt San Clemente-Class tankers for subsidiaries of Overseas Shipholding Group, Inc.

NASSCO is owned equally by Kaiser Industries Corp. and Morrison-Knudsen Company, Inc., and is managed by Kaiser Industries.

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