protective cover
A protective cover (English: shelter deck) is a ship deck on a ship. Edit Source Text Details
By definition of authorities and classification societies, a protective deck is a lightly built closed deck above the main deck.
The protective deck developed from the savings deck. This deck, initially made of slats, was often built on cargo ships with passenger facilities as an additional deck for connecting existing deck structures at the beginning of the iron shipbuilding to create an additional (often temporary) covered deck area for passengers. Later, the protective deck was built from iron or steel. It was opened by measurement openings with prescribed dimensions as well as by the underlying bulkheads and thus excluded from the measurement. Both for savings as well as for protection decks, classification societies issued their own rules regarding the materials to be chosen and their strengths. Ships with protective deck above the survey deck have been classified accordingly as protective covers. Edit source text
wiki