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, , loss of stability due to cargo shifting or flooding, or in high speed boats, from turning too fast. If a capsized vessel has enough flotation to prevent sinking, it may recover on its own in changing conditions or through mechanical work if it is not stable inverted. Vessels of this design are called self-righting. Small vessels In dinghy sailing, a practical distinction can be made between being knocked down (to 90 degrees; on its beam-ends, figuratively) which is called a capsize, and being inverted, which is called being turtled. 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 capsizing and righting the vessel again can be the fastest means of draining water from the boat. Capsizing (but not necessarily turtling) is an inherent part of dinghy sailing. It is not a question of "if" but a question of "when". For those who do not want the experience, a keelboat monohull has physics on its side. But even yachts can capsize and turtle in extraordinary conditions, so design considerations are important. Such events can overcome skill and experience; boats need to be appropriate for foreseeable conditions. 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 that 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. Kayak rolling, in which paddlers intentionally capsize and right themselves (in synchrony, as many times as possible in a given interval, or in as many different ways as possible) is also a competitive sport, especially in Greenland. Sailing vessels' "capsize ratio" is commonly published as a guideline for zones of safe operation — less than 2.0 means as a rule-of-thumb suitability for offshore navigation. However its crude