Double Bottom Tank : The lower most Tanks under the Cargo Hold are called the Double Bottom Tanks. They are like double skin to the ship and protect ship's bottom
Shrikant Hathi & Binita Hathi, Maritime Practice in India, Shipping Glossary (7th Ed.), published by the law firm BRUS Chambers, Mumbai, India, 2012. http://bruschambers.com/marine/memo51.htm, (Mrtm - Brit) {567}