Capsize
Encyclopedia
Capsizing is an act of tipping over a boat
or ship
to disable it. The act of reversing a capsized vessel is called righting.
If a capsized vessel has sufficient flotation to prevent sinking, it may recover on its own if the stability is such that it is not stable
inverted. Vessels of this design are called self-righting.
A capsized kayak
may be righted with a roll
or eskimo rescue
. As long as the kayaker knows how to react, the water is not too shallow, and the location is not close to dangers which would require evasive action by the kayaker - which cannot be taken while capsized - capsizing itself is usually not considered dangerous. In whitewater kayaking
, capsizing occurs frequently and is accepted as an ordinary part of the sport; depending on personal experience, the difficulty of the water, and the preferred kayaking style (esp. playboating), many whitewater kayakers likely capsize several times each time they go kayaking.
For sailing vessels, the "capsize ratio" is a commonly published number used as a guideline for safe operation. A ratio of less than 2.0 is considered suitable for offshore operation. The capsize ratio is only a guideline, since there are many factors involved in vessel stability.
A vessel may be designated as "self-righting" if it is designed to be able to capsize then return to upright without intervention (with or without crew onboard). Small craft intended as lifeboats
with rigid (versus inflatable) hulls are almost universally self-righting if they have been designed in the past few decades.
over stern
in extreme waves
. This is normally catastrophic for larger ships, and smaller yachts can be dismasted (i.e., lose their masts
and rigging
) due to the drag as the boat
is forced to roll over.
Among ship types, the RORO
is more prone to capsize due to having large open car decks near to the waterline
. If the watertight car-deck doors fail through damage or mis-management (as in the MS Herald of Free Enterprise where the doors were accidentally left open), water entering the car-deck may cause the free surface effect
leading to a capsize. Additionally, as the ship rolls, vehicles can break free and slide down adversely altering the centre of gravity and accelerating the roll and possibly turning an otherwise recoverable roll into a capsize.
In competitive yacht racing
, a capsized boat has certain special rights as it cannot maneuver. A boat is deemed capsized when the mast is touching the water; when it is fully inverted, it is said to have turned turtle
or turtled. Good racers can often recover from a capsize with minimal loss of time.
The capsize can result from extreme broaching
, especially if the keel
has insufficient leverage to tilt the vessel upright.
Motor life boats are designed to be self righting if capsized but most other motorboats are not.
in a safe location with supervision at least once to become acquainted with their boat's floating properties and the capsize process. The boat should then be righted, bailed out, and the sails reset, so that in the event of an uncontrolled capsize, the boat and its occupants are familiar with the procedure and may self recover.
Most small monohull sailboats can normally be righted by standing or pulling down on the centreboard or daggerboard to lift the mast clear of the water. Depending on the design of the hull
, the boat's righting moment will normally take effect once the mast is around 30 degrees from horizontal and help pull the boat vertical
. Righting a Catamaran
that is lying on its side involves using a righting line fed over the upper hull. The crew stands on the lower hull and pulls back on the righting line. In small catamarans such as the Hobie 16
it is imperative that at least one crew member assumes this task as soon as possible as there is a chance that the boat will turn turtle and then would then be extremely difficult to recover without assistance. Some catamarans may use a small flotation device mounted at the tip of the mast to ensure that the craft cannot assume an inverted position, or at least that a fully inverted position is not stable (i.e. it would come to a position where the mast is lying on the surface of the water which would be preferable to fully inverted).
In both cases, having a crew member lift the end of the mast
out of the water may help speed the process, as the greatest challenge of righting a capsized boat is shedding the weight of the water from the sails. A helpful step is where possible (on a loose footed sail) to disconnect the clew of the sail from the boom, which prevents the sail from scooping up water as the sail lifts out of the water. The bow
of the capsized vessel should be pointed towards the wind so that when the sail starts to lift out of the water the wind can catch underneath the sail and help right the boat.
Care should be taken not to let the boat swing all the way over and capsize on the other side, frequently with the crew on the bottom. This is more likely if the boat is not pointed into the wind.
Boat
A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...
or ship
Ship
Since the end of the age of sail a ship has been any large buoyant marine vessel. Ships are generally distinguished from boats based on size and cargo or passenger capacity. Ships are used on lakes, seas, and rivers for a variety of activities, such as the transport of people or goods, fishing,...
to disable it. The act of reversing a capsized vessel is called righting.
If a capsized vessel has sufficient flotation to prevent sinking, it may recover on its own if the stability is such that it is not stable
Ship stability
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. Stability calculations focus on the center of gravity and center of buoyancy of vessels and on how these interact....
inverted. Vessels of this design are called self-righting.
Small vessels
Small dinghies frequently capsize in the normal course of use and can usually be recovered by the crew. Some types of dinghy are occasionally deliberately capsized, as righting the vessel again can be the fastest means of draining water from the boat.A capsized kayak
Kayak
A kayak is a small, relatively narrow, human-powered boat primarily designed to be manually propelled by means of a double blade paddle.The traditional kayak has a covered deck and one or more cockpits, each seating one paddler...
may be righted with a roll
Kayak roll
The Kayak Roll is the act of righting a capsized kayak by use of body motion and/or a paddle. Typically this is done by lifting the torso towards the surface, flicking the hips to right the kayak halfway up and applying a righting force by means of the paddle while tucking close to the front or...
or eskimo rescue
Eskimo Rescue
An Eskimo Rescue or Bow Rescue is a Kayaking manoeuvre performed to recover from a capsize. After drawing attention to the capsize , the Kayaker runs their hands along the side of the Kayak until another comes up perpendicular to the capsized Kayak...
. As long as the kayaker knows how to react, the water is not too shallow, and the location is not close to dangers which would require evasive action by the kayaker - which cannot be taken while capsized - capsizing itself is usually not considered dangerous. In whitewater kayaking
Whitewater kayaking
Whitewater kayaking is the sport of paddling a kayak on a moving body of water, typically a whitewater river. Whitewater kayaking can range from simple, carefree gently moving water, to demanding, dangerous whitewater. River rapids are graded like ski runs according to the difficulty, danger or...
, capsizing occurs frequently and is accepted as an ordinary part of the sport; depending on personal experience, the difficulty of the water, and the preferred kayaking style (esp. playboating), many whitewater kayakers likely capsize several times each time they go kayaking.
For sailing vessels, the "capsize ratio" is a commonly published number used as a guideline for safe operation. A ratio of less than 2.0 is considered suitable for offshore operation. The capsize ratio is only a guideline, since there are many factors involved in vessel stability.
A vessel may be designated as "self-righting" if it is designed to be able to capsize then return to upright without intervention (with or without crew onboard). Small craft intended as lifeboats
Lifeboat (rescue)
A rescue lifeboat is a boat rescue craft which is used to attend a vessel in distress, or its survivors, to rescue crewmen and passengers. It can be hand pulled, sail powered or powered by an engine...
with rigid (versus inflatable) hulls are almost universally self-righting if they have been designed in the past few decades.
Large vessels
In a storm, even large vessels may be rolled by being hit broadside by a large wave or "pitchpoled" stemStem (ship)
The stem is the very most forward part of a boat or ship's bow and is an extension of the keel itself and curves up to the wale of the boat. The stem is more often found on wooden boats or ships, but not exclusively...
over stern
Stern
The stern is the rear or aft-most part of a ship or boat, technically defined as the area built up over the sternpost, extending upwards from the counter rail to the taffrail. The stern lies opposite of the bow, the foremost part of a ship. Originally, the term only referred to the aft port section...
in extreme waves
Ocean surface wave
In fluid dynamics, wind waves or, more precisely, wind-generated waves are surface waves that occur on the free surface of oceans, seas, lakes, rivers, and canals or even on small puddles and ponds. They usually result from the wind blowing over a vast enough stretch of fluid surface. Waves in the...
. This is normally catastrophic for larger ships, and smaller yachts can be dismasted (i.e., lose their masts
Mast (sailing)
The mast of a sailing vessel is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship...
and rigging
Rigging
Rigging is the apparatus through which the force of the wind is used to propel sailboats and sailing ships forward. This includes masts, yards, sails, and cordage.-Terms and classifications:...
) due to the drag as the boat
Boat
A boat is a watercraft of any size designed to float or plane, to provide passage across water. Usually this water will be inland or in protected coastal areas. However, boats such as the whaleboat were designed to be operated from a ship in an offshore environment. In naval terms, a boat is a...
is forced to roll over.
Among ship types, the RORO
RORO
Roll-on/roll-off ships are vessels designed to carry wheeled cargo such as automobiles, trucks, semi-trailer trucks, trailers or railroad cars that are driven on and off the ship on their own wheels...
is more prone to capsize due to having large open car decks near to the waterline
Waterline
The term "waterline" generally refers to the line where the hull of a ship meets the water surface. It is also the name of a special marking, also known as the national Load Line or Plimsoll Line, to be positioned amidships, that indicates the draft of the ship and the legal limit to which a ship...
. If the watertight car-deck doors fail through damage or mis-management (as in the MS Herald of Free Enterprise where the doors were accidentally left open), water entering the car-deck may cause the free surface effect
Free Surface Effect
The free surface effect is one of several mechanisms which can cause a craft to become unstable and roll over . It refers to the tendency of liquids — and of aggregates of small solid objects, like seeds, gravel, or crushed ore which can act as liquids — to slosh about: to move in response to...
leading to a capsize. Additionally, as the ship rolls, vehicles can break free and slide down adversely altering the centre of gravity and accelerating the roll and possibly turning an otherwise recoverable roll into a capsize.
Competition
Yacht racing
Yacht racing is the sport of competitive yachting.While sailing groups organize the most active and popular competitive yachting, other boating events are also held world-wide: speed motorboat racing; competitive canoeing, kayaking, and rowing; model yachting; and navigational contests Yacht racing...
, a capsized boat has certain special rights as it cannot maneuver. A boat is deemed capsized when the mast is touching the water; when it is fully inverted, it is said to have turned turtle
Turtling (sailing)
In dinghy sailing, a boat is said to be turtling when the boat is fully inverted with the mast pointing down to the seabed. The name stems from the appearance of the upside-down boat, similar to the shell of a sea turtle....
or turtled. Good racers can often recover from a capsize with minimal loss of time.
The capsize can result from extreme broaching
Broach (sailing)
A sailboat broaches when its heading suddenly changes towards the wind due to wind/sail interactions for which the rudder cannot compensate. This causes the boat to roll dangerously and if not controlled may lead to a capsize...
, especially if the keel
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...
has insufficient leverage to tilt the vessel upright.
Motor life boats are designed to be self righting if capsized but most other motorboats are not.
Training
Intermediate sailors are encouraged to capsize their dinghyDinghy
A dinghy is a type of small boat, often carried or towed for use as a ship's boat by a larger vessel. It is a loanword from either Bengali or Urdu. The term can also refer to small racing yachts or recreational open sailing boats. Utility dinghies are usually rowboats or have an outboard motor,...
in a safe location with supervision at least once to become acquainted with their boat's floating properties and the capsize process. The boat should then be righted, bailed out, and the sails reset, so that in the event of an uncontrolled capsize, the boat and its occupants are familiar with the procedure and may self recover.
Most small monohull sailboats can normally be righted by standing or pulling down on the centreboard or daggerboard to lift the mast clear of the water. Depending on the design of the hull
Hull (watercraft)
A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
, the boat's righting moment will normally take effect once the mast is around 30 degrees from horizontal and help pull the boat vertical
Vertical direction
In astronomy, geography, geometry and related sciences and contexts, a direction passing by a given point is said to be vertical if it is locally aligned with the gradient of the gravity field, i.e., with the direction of the gravitational force at that point...
. Righting a Catamaran
Catamaran
A catamaran is a type of multihulled boat or ship consisting of two hulls, or vakas, joined by some structure, the most basic being a frame, formed of akas...
that is lying on its side involves using a righting line fed over the upper hull. The crew stands on the lower hull and pulls back on the righting line. In small catamarans such as the Hobie 16
Hobie 16
See Also: Hobie 16 subsection of Hobie cat entryThe ISAF International Class Hobie 16 is a popular catamaran manufactured by the Hobie Cat Company for racing and day sailing...
it is imperative that at least one crew member assumes this task as soon as possible as there is a chance that the boat will turn turtle and then would then be extremely difficult to recover without assistance. Some catamarans may use a small flotation device mounted at the tip of the mast to ensure that the craft cannot assume an inverted position, or at least that a fully inverted position is not stable (i.e. it would come to a position where the mast is lying on the surface of the water which would be preferable to fully inverted).
In both cases, having a crew member lift the end of the mast
Mast (sailing)
The mast of a sailing vessel is a tall, vertical, or near vertical, spar, or arrangement of spars, which supports the sails. Large ships have several masts, with the size and configuration depending on the style of ship...
out of the water may help speed the process, as the greatest challenge of righting a capsized boat is shedding the weight of the water from the sails. A helpful step is where possible (on a loose footed sail) to disconnect the clew of the sail from the boom, which prevents the sail from scooping up water as the sail lifts out of the water. The bow
Bow (ship)
The bow is a nautical term that refers to the forward part of the hull of a ship or boat, the point that is most forward when the vessel is underway. Both of the adjectives fore and forward mean towards the bow...
of the capsized vessel should be pointed towards the wind so that when the sail starts to lift out of the water the wind can catch underneath the sail and help right the boat.
Care should be taken not to let the boat swing all the way over and capsize on the other side, frequently with the crew on the bottom. This is more likely if the boat is not pointed into the wind.
Notable capsizings
- Mary RoseMary RoseThe Mary Rose was a carrack-type warship of the English Tudor navy of King Henry VIII. After serving for 33 years in several wars against France, Scotland, and Brittany and after being substantially rebuilt in 1536, she saw her last action on 1545. While leading the attack on the galleys of a...
, 19 July 1545, English carrack, 380 dead. - Vasa (ship), 10 August 1628, Swedish Warship, maiden voyage, 30-50 dead.
- SS Eastland, 1915, excursion boat, 845 dead, greatest loss of life on the Great LakesGreat LakesThe Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...
. - Szent IstvánSMS Szent IstvánSMS Szent István was a dreadnought , the only one built in the Hungarian part of Austria-Hungary. The Ganz & Company's Danubius yard in Hungarian-owned Fiume was awarded the contract to build the battleship in return for the Hungarian government agreeing to the 1910 and 1911 naval budgets...
, 1918, Austro-Hungarian capital warship, torpedoTorpedoThe modern torpedo is a self-propelled missile weapon with an explosive warhead, launched above or below the water surface, propelled underwater towards a target, and designed to detonate either on contact with it or in proximity to it.The term torpedo was originally employed for...
ed, 89 dead. - USS OklahomaUSS Oklahoma (BB-37)USS Oklahoma , the only ship of the United States Navy to ever be named for the 46th state, was a World War I-era battleship and the second of two ships in her class; her sister ship was . She, along with her sister, were the first two U.S...
, 7 December 1941, U.S. battleship torpedoed at Pearl HarborAttack on Pearl HarborThe attack on Pearl Harbor was a surprise military strike conducted by the Imperial Japanese Navy against the United States naval base at Pearl Harbor, Hawaii, on the morning of December 7, 1941...
, 415 missing or killed. - SS NormandieSS NormandieSS Normandie was an ocean liner built in Saint-Nazaire, France for the French Line Compagnie Générale Transatlantique. She entered service in 1935 as the largest and fastest passenger ship afloat; she is still the most powerful steam turbo-electric-propelled passenger ship ever built.Her novel...
, 9 February 1942, aka USS Lafayette, no casualties. - TirpitzGerman battleship TirpitzTirpitz was the second of two s built for the German Kriegsmarine during World War II. Named after Grand Admiral Alfred von Tirpitz, the architect of the Imperial Navy, the ship was laid down at the Kriegsmarinewerft in Wilhelmshaven in November 1936 and launched two and a half years later in April...
, 12 November 1944, almost 1000 dead. - YamatoJapanese battleship Yamato, named after the ancient Japanese Yamato Province, was the lead ship of the Yamato class of battleships that served with the Imperial Japanese Navy during World War II. She and her sister ship, Musashi, were the heaviest and most powerfully armed battleships ever constructed, displacing...
, 7 April 1945, 2,475 dead. - Novorossiisk, 29 October 1955, 608 dead.
- Andrea DoriaSS Andrea DoriaSS Andrea Doria[p] was an ocean liner for the Italian Line home ported in Genoa, Italy, most famous for its sinking in 1956, when 46 people died. Named after the 16th-century Genoese admiral Andrea Doria, the ship had a gross register tonnage of 29,100 and a capacity of about 1,200 passengers and...
, 25 July 1956, killing 46 passengers at the area of the Stockholm's impact. - Herald of Free Enterprise, 6 March 1987, killing 193 passengers.
- Jan HeweliuszJan Heweliusz (ship)The M/S Jan Heweliusz, owned by PLO and operated by its daughter company PLO EuroAfrica, was a Polish ferry named after astronomer Johannes Hevelius .Built in Norway in 1977, the ferry served on the route Ystad-Świnoujście...
, 14 January 1993, leaving 54 people dead. - Estonia, 28 September 1994, killing 852 passengers.
- La JoolaMV JoolaMV Le Joola was a Senegalese government-owned ferry that capsized off the coast of The Gambia on September 26, 2002. The disaster resulted in the deaths of at least 1,863 people. The sinking of the ferry Joola is thought to be the second-worst non-military maritime disaster in number of lives lost...
, 26 September 2002, Senegalese ferry, at least 1,863 dead. - M.V. Rocknes, 19 January 2004, DutchNetherlandsThe Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
rock discharge vessel, capsized south of Bergen, Norway, killing 18 of 30 crew. - MS al-Salam Boccaccio 98, 3 February 2006, resulting in an estimated 1020 dead.
- MV Demas VictoryMV Demas VictoryThe MV Demas Victory, a Dubai-based supply ship which sails to offshore oil and gas platforms, capsized 10 nautical miles off the coast of the Qatari capital city of Doha on Tuesday 30 June 2009 at 6:30 a.m. local time. The disaster resulted in over 30 missing of the 35 reported to be on board. ...
, 30 June 2009, which sails to offshore oil and gas platforms capsized off the coast of QatarQatarQatar , also known as the State of Qatar or locally Dawlat Qaṭar, is a sovereign Arab state, located in the Middle East, occupying the small Qatar Peninsula on the northeasterly coast of the much larger Arabian Peninsula. Its sole land border is with Saudi Arabia to the south, with the rest of its...
i capital city of DohaDohaDoha is the capital city of the state of Qatar. Located on the Persian Gulf, it had a population of 998,651 in 2008, and is also one of the municipalities of Qatar...
.
See Also
- Turtling (sailing)Turtling (sailing)In dinghy sailing, a boat is said to be turtling when the boat is fully inverted with the mast pointing down to the seabed. The name stems from the appearance of the upside-down boat, similar to the shell of a sea turtle....
- a full capsize in which the mast and sail are fully submerged.