They are covered by the layer of watertight plating called the inner bottom or tank top, and thus prevent the ship becoming flooded should the outer bottom plating be holed .
Agqunywe ngumphezulu wesigqumo esingangeni manzi esibizwa ngokuba ngumphantsi wangaphakathi okanye umphezulu wetanki, ngenxa yoko inqanawa ithi ikhuseleke ekubeni iphuphumale nje wakugqobhoka umphandle wesigqumo.