The earliest boats were small and had no decks. Crew and cargo together occupied the space created by the hull. As ship sizes grew, they were improved with enclosed decks that created storage space within the hull we now call holds. Cargo, living quarters, and supplies could be stored below decks, away from the elements and out of the crew’s way. The crew operated the ship from the top deck, which remained open to the elements. Enclosed decks greatly improved the carrying capacity and productivity of ships.