the principal part of a ship, consisting of the shell and the frame (framing).
The hull provides buoyancy and general and local strength to the ship and makes it possible to arrange a place for people, cargo, equipment, weaponry, and other things according to the functions of the ship. The outer shell of the hull (bottom and side plating and deck surface) makes it watertight; it may be multitiered. The inside shells, which divide the hull into compartments, are called second bottom, second or inside walls, lower decks, platforms, and bulkheads. The frame and plating are essential elements of any ship hull; the use of decks and bulk-heads depends on the function of the ship. A distinction is made between the main hull and above-deck structures arranged on the continuous top deck (ship superstructures, rooms, masts, and the like).
In modern shipbuilding steel, aluminum and titanium alloys, plastics, wood, and reinforced concrete are used for building the hulls of ships. What is called hull steel in the form of sheets, strips, rolled sections (bulb bar, T -section, angle and shaped) with maximum yield between 220 and 700 meganewtons per sq m (from 22 to 70 kilograms = force per sq mm) has become most common for building the hulls of ships of different sizes and designations. The individual steel parts of the hull are connected by welding and in some cases by riveting. Aluminum alloys, wood, and plastics are used basically for building the hulls of small ships and for above-deck structures. Titanium alloys are used primarily for building the strong hulls of submarines, and reinforced concrete is used for the hulls of barges, docks, and landing stages.
A. I. MAKSIMADZHI