Single hull tanker

A single-hull tanker is an oil tanker whose cargo tanks are bounded directly by the outer shell plating, with no double hull or double bottom protecting against grounding or collision spills. After the Erika (1999) and Prestige (2002) losses, IMO accelerated their phase-out under MARPOL Annex I Regulation 13G, later renumbered Regulation 20. Category 1 tankers (pre-MARPOL) went out by 2005 and Category 2 and 3 by 2010, with limited flag-state extensions to 2015 or the 25th year subject to the Condition Assessment Scheme (CAS). The global crude and product tanker fleet is now double hull.