Deck (ship) - Structure

Structure

The purpose of the upper or primary deck is structural, and only secondarily to provide weather-tightness, and to support people and equipment. The deck serves as the lid to the complex box girder which is the hull. It resists tension, compression, and racking forces. The deck's scantling is usually the same as the topsides, or might be heavier if the deck is expected to carry heavier loads (for example a container ship). The deck will be reinforced around deck fittings such as the capstan, cleats, or bollards.

On ships with more than one level, deck refers to the level itself. The actual floor surface is called the sole, the term deck refers to a structural member tying the ships frames or ribs together over the keel. In modern ships, the interior decks are usually numbered from the primary deck, which is #1, downward and upward. So the first deck below the primary deck will be #2, and the first above the primary deck will be #A2 or #S2 (for "Above" or "Superstructure"). However, ships may also call decks by common names, or (especially on cruise ships) may invent fanciful and romantic names for a specific deck or area of that specific ship, such as the Lido deck of the Princess Cruises' Love Boat.

Equipment mounted on deck, such as the ship's wheel, binnacle, fife rails, and so forth, may be collectively referred to as deck furniture. Weather decks in western designs evolved from having structures fore and aft (forward or front and aft or The Rear of the ship mostly clear, then in the 19th century pilothouses/wheelhouses and deckhouses began to appear, eventually developing into the superstructure of modern ships. Eastern designs developed earlier, with efficient middle decks and minimalist fore and aft cabin structures across a range of designs.