In the Genesis account of Noah’s Ark, the vessel was instructed to have three decks. Genesis 6:16 says the Ark was to have lower, second, and third decks.
The verse also describes a door in the side of the Ark and an opening or window near the top. These details accompany the dimensions given earlier and portray the vessel as a large enclosed structure with multiple internal levels.
The three-deck description is not the same as saying the Ark had three separate boats or three masts. It refers to stacked internal levels, presumably providing space for Noah’s household, provisions, and the animals. Artistic reconstructions often add features not specified in Genesis, so the biblical details are best kept distinct from later visual designs.