Ceiling.The ceiling consists of wooden planks laid on top of the double bottom tanks. The planks are laid longitudinally and prevent contact between the cargo and the double bottom.
In some cargo vessels a ceiling is only fitted below the hatchway as a platform for cargo. The ceiling in itself is not sufficient as dunnage for bagged cargo and extra dunnage, e.g., is required, in order to ensure a good outturn. The ceiling and cargo battens are considered as permanent dunnage in contrast with dunnage such as mats, boards, burlap, paper, etc, which is “portable” or “temporary” dunnage.