In response to continuing oil spills, double-hull construction for oil tankers became mandatory in 1993 by order of the Maritime Environmental Protection Committee of the International Maritime Organization (IMO). Compared to single-hull tankers, the use of double-hull construction has resulted in a distinct reduction in the probability of oil spills resulting from collision or grounding. At the same time, this new construction has brought new problems for ship owners and operators. One problem is the increased painting area that resulted from the increased ballast tank surface area subject to a corrosive environment. Another is the increased complexity of maintenance and inspection required in these tanks. In the normal concept of the double-hull tanker, the spaces in the double-sides and double bottom are used as ballast water tanks. The surface of the bulkheads between the ballast and cargo oil tanks are exposed to a severely corrosive environment. The ballast tanks must be stringently inspected and maintained for the double-hull tanker to satisfactorily prevent oil spills. NKK developed a new concept for double-hulled oil tankers that has a void double-hull space. The void double-hull spaces are subject to minimal corrosion, which reduces maintenance and inspection. An economic evaluation of the new concept shows that the life cycle cost is less than that of conventional double-hulled tankers because of the reduced maintenance costs. When the vessel is used for a long period of time, such as 20 years, the reduction in operating costs of this concept ensures benefits in excess of that obtainable with a comparable conventional VLCC (Very Large Cargo Carrier). In terms of performance in preventing oil spills, the void hull tanker is equal to the conventional VLCC, and the slightly narrower double-hull space may be compensated for by appropriate reinforcement to ensure a high level of reliability.
A new concept for double-hulled oil tanker
Ein neues Konzept für die Doppelhülle von Tankern
NKK Technical Review ; 75 ; 44-50
1996
7 Seiten, 9 Bilder, 4 Tabellen, 5 Quellen
Aufsatz (Zeitschrift)
Englisch
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