The angle of list is the degree to which a vessel heels (leans or tilts) to either port or starboard at equilibrium—with no external forces acting upon it. [1] If a listing ship goes beyond the point where a righting moment will keep it afloat, it will capsize and potentially sink. [2]
Listing is caused by the off-centerline distribution of weight aboard due to uneven loading or to flooding. [3] By contrast, roll is the dynamic movement from side to side caused by waves.
SS Eastland was a passenger ship based in Chicago and used for tours. On 24 July 1915, the ship rolled over onto its side while tied to a dock in the Chicago River. In total, 844 passengers and crew were killed in what was the largest loss of life from a single shipwreck on the Great Lakes.
Naval architecture, or naval engineering, is an engineering discipline incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the engineering design process, shipbuilding, maintenance, and operation of marine vessels and structures. Naval architecture involves basic and applied research, design, development, design evaluation (classification) and calculations during all stages of the life of a marine vehicle. Preliminary design of the vessel, its detailed design, construction, trials, operation and maintenance, launching and dry-docking are the main activities involved. Ship design calculations are also required for ships being modified. Naval architecture also involves formulation of safety regulations and damage-control rules and the approval and certification of ship designs to meet statutory and non-statutory requirements.
Seamanship is the art, knowledge and competence of operating a ship, boat or other craft on water. The Oxford Dictionary states that seamanship is "The skill, techniques, or practice of handling a ship or boat at sea."
A Bruce foil is a variant of the leeboard, consisting of a foil typically mounted on an outrigger and always set at an angle to provide both lateral and vertical force. It was invented by Edmond Bruce in the early 1960s, and first published in the Amateur Yacht Research Society publication in April 1965.
HMS Captain was a major warship built for the Royal Navy as a semi-private venture, following a dispute between the designer and the Admiralty. With wrought-iron armour, steam propulsion, and the main battery mounted in rotating armoured turrets, the ship was, at first appearance, quite innovative and formidable. However, poor design and design changes resulted in a vessel that was overweight and ultimately unstable. In terms of seaworthiness she was reported as closely comparable to the higher freeboard turret-ship HMS Monarch, but her reduced freeboard added a sense of "sluggishness". The Captain capsized in heavy seas, only five months after being commissioned, with the loss of nearly 500 lives.
The metacentric height (GM) is a measurement of the initial static stability of a floating body. It is calculated as the distance between the centre of gravity of a ship and its metacentre. A larger metacentric height implies greater initial stability against overturning. The metacentric height also influences the natural period of rolling of a hull, with very large metacentric heights being associated with shorter periods of roll which are uncomfortable for passengers. Hence, a sufficiently, but not excessively, high metacentric height is considered ideal for passenger ships.
Sailing ships frequently encounter difficult conditions, whether by storm or combat, and the crew frequently called upon to cope with accidents, ranging from the parting of a single line to the whole destruction of the rigging, and from running aground to fire.
Albatross, originally named Albatros, later Alk, was a sailing ship that became famous when she sank in 1961 with a group of American teenagers on board. The events were the basis for the highly fictionalized 1996 film White Squall.
Capsizing or keeling over occurs when a boat or ship is rolled on its side or further by wave action, instability or wind force beyond the angle of positive static stability or it is upside down in the water. The act of recovering a vessel from a capsize is called righting. Capsize may result from broaching, knockdown, loss of stability due to cargo shifting or flooding, or in high speed boats, from turning too fast.
Ballast is used in ships to provide moment to resist the lateral forces on the hull. Insufficiently ballasted boats tend to tip or heel excessively in high winds. Too much heel may result in the vessel capsizing. If a sailing vessel needs to voyage without cargo, then ballast of little or no value will be loaded to keep the vessel upright. Some or all of this ballast will then be discarded when cargo is loaded.
A broach is an abrupt, involuntary change in a vessel's course, towards the wind, resulting from loss of directional control, when the vessel's rudder becomes ineffective. This can be caused by wind or wave action. A wind gust can heel (lean) a sailing vessel, lifting its rudder out of the water. Both power and sailing vessels can broach when wave action reduces the effectiveness of the rudder. This risk occurs when traveling in the same general direction as the waves are moving. The loss of control from either cause usually leaves the vessel beam-on to the sea, and in more severe cases the rolling moment may cause a capsize.
Captain Cowper Phipps Coles, C.B., R.N., was an English naval captain with the Royal Navy. Coles was also an inventor; in 1859, he was the first to patent a design for a revolving gun turret. Upon appealing for public support, his turrets were installed on HMS Prince Albert and HMS Royal Sovereign. Coles died in a maritime accident in 1870 when HMS Captain, an experimental warship built to his designs, capsized and sank with him on board.
Ship motions are defined by the six degrees of freedom that a ship, boat, or other watercraft, or indeed any conveyance, can experience.
In dinghy sailing, a boat is said to be turtling or to turn turtle when the boat is fully inverted with the mast pointing down to the lake bottom, riverbed, or seabed. The name stems from the appearance of the upside-down boat, similar to the carapace of a sea turtle. The term can be applied to any vessel; turning turtle is less frequent but more dangerous on ships than on smaller boats. It is rarer but more hazardous for multihulls than for monohulls, because of multihulls are harder to flip in both directions. Measures can be taken to prevent a capsize from becoming a turtle.
Angle of loll is the state of a ship that is unstable when upright and therefore takes on an angle of heel to either port or starboard.
Ship stability is an area of naval architecture and ship design that deals with how a ship behaves at sea, both in still water and in waves, whether intact or damaged. Stability calculations focus on centers of gravity, centers of buoyancy, the metacenters of vessels, and on how these interact.
In sailing, the limit of positive stability (LPS) or angle of vanishing stability (AVS) is the angle from the vertical at which a boat will no longer stay upright but will capsize, becoming inverted, or turtled.
The Hatsuharu-class destroyers were a class of Imperial Japanese Navy destroyers in the service before and during World War II. The final two vessels in the class, completed after modifications to the design, are sometimes considered a separate "Ariake class".
Ballast is dense material used as a weight to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, submarine, or other floating structure that holds water is called a ballast tank. Water should move in and out from the ballast tank to balance the ship. In a vessel that travels on the water, the ballast will remain below the water level, to counteract the effects of weight above the water level. The ballast may be redistributed in the vessel or disposed of altogether to change its effects on the movement of the vessel.
Secondary stability, also known as reserve stability, is a boat or ship's ability to right itself at large angles of heel, as opposed to primary or initial stability, the boat's tendency to stay laterally upright when tilted to low (<10°) angles.