Tween decks and Bulkheads

Tween decks are generally used in multi-purpose cargo ships to split the cargo hold longitudinally to have more than one deck.

The upper deck is called the main deck or weather deck, and the next lower deck is the tween deck and bottom of hold is tank top.

Cargo ships that have fittings to carry standard shipping containers and retractable tween decks (that can be moved out of the way) so that the ship can carry bulk cargo are known as multipurpose vessels.

Bulkheads are placed transversally to split the cargo hold room more than 1 hold to carry different cargo.