Double bottom. The double bottom, extending from the forepeak to afterpeak tank, considerably increases the safety of the vessel in case of serious bottom damage by grounding, which might otherwise result in flooding of the cargo holds or engine room. Moreover, the double bottom, which is subdivided into a number of tanks, is suitable for carriage of water ballast, fuel oil, fresh water etc., and increases the longitudinal strength of the vessel.
The double bottom tanks are accessible from the shipβs holds or tunnel by means of manholes, which are closed by watertight covers with bolts.