Double-hulled tanker

They reduce the likelihood of leaks occurring compared to single-hulled tankers, and their ability to prevent or reduce oil spills led to double hulls being standardized for oil tankers and other types of ships including by the International Convention for the Prevention of Pollution from Ships or MARPOL Convention.

Research of impact damage of ships has revealed that double-hulled tankers are unlikely to perforate both hulls in a collision, preventing oil from seeping out.

[1] In 1992, MARPOL was amended, making it "mandatory for tankers of 5,000 dwt and more ordered after 6 July 1993 to be fitted with double hulls, or an alternative design approved by IMO".

However, in the aftermath of the Erika incident of the coast off France in December 1999, members of IMO adopted a revised schedule for the phase-out of single-hull tankers, which came into effect on 1 September 2003, with further amendments validated on 5 April 2005.

[2] Double-hulled tankers have a more complex design and structure than their single-hulled counterparts, which means that they require more maintenance and care in operating, which if not subject to responsible monitoring and policing, may cause problems.