BULKHEAD ( bulk or balk, Ger. Italke, beam, bar). The name given to a variety of con structions in civil and marine engineering. In tunneling a bulkhead is a vertical partition of timber or nuusonra intended to prevent the passage of water. air. or mud. Tunnel bulkheads may be made solid or they may Be provided with a door to give passage to workmen and materials. In harbor work the term bulkhead is often ap plied to the sea-wall which marks the shore-line, and from which the piers or quays project out into the water.
On shipboard a bulkhead is a partition sepa rating the compartments of a ship. In modern vessels bulkheads are chiefly of steel. like the rest of the hull. All vessels are now divided into several compartments by water-tight bulkheads as a matter of safety. so that the breaching and consequent tilling of one compartment with water need not necessarily cause the ship to founder. Water-tight bulkheads are both transverse and longitudinal. the former dividing the ship into
several great compartments, and the latter sub dividing these. In addition to the main bulk heads. many parts of war-ships. like magazines. shell-rooms. etc., are especially inclosed. In mei- tluant vessels the prineipal transverse bulkheads are without any holes through them below the water line: hut in men-of-•ar the necessity for communication below has the cut ting of doors which are designed to he water tight. but many of them are probably not wholly so. fn ships having two or three screws, the engines for each are in separate compartments, the boilers are placed in one or more compart ments, and the coal-bunkers are divided into sev eral. In most merchant vessels a collision bulk head is fitted a short distance from the stem, and several steamers have been saved by it from foundering.