When the double bottom height is 2m with 0.6m deep longitudinals, we have the unidirectional stiffened double bottom with no transverse webs inside double bottom.
This construction is simple and double bottom spaces can be easily ventilated and washed.
As well as the basic requirement for tankers to have double hulls, there are now additional regulatory measures stipulating increased survey and maintenance (including access for inspection) on tankers.
It has been argued that similar standards of inspection and maintenance of single hulled ships would have resulted in a similar improvement to safety, but at a lower cost.
