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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 or seabed. The name stems from the appearance of the upside-down boat, similar to the carapace, that is the top shell of a sea turtle.〔 at Internet Archive〕〔However, "to turn turtle" means putting a turtle on its back by grabbing it by the flipper, and conversely is used to refer to a vessel that has turned upside down, or which has cast off its crew. 〕 〔A related nautical turtle metaphor is the term Turtleback Deck or "''deck, turtle'' nautical: A term applied to a weather deck that is rounded over from the shell of the ship so that it has a shape similar to the back of a turtle. Used on ships of the whaleback type and on the forward weather deck of torpedo boats." (【引用サイトリンク】USS Abbot (DD-629)">url=http://abbot.us/DD629/dictionary/ )〕 The term can be applied to any vessel; turning turtle is less frequent but more dangerous on ships than on smaller boats.〔In larger vessels a capsize almost inevitably leads to a sinking. "To turn upside down, and usually, to sink. There is no vessel so large that the largest ocean wave, taken broadside, cannot capsize." 〕 Relative to monohulls, it is more hazardous on multihulls, because of their inherent stability in an inverted position. Measures can be taken to prevent a capsize (where the boat is knocked over but not yet inverted) from becoming a turtle (with bottom up).〔〔 ==Definition and prevention== When a boat is "turned over completely" is has turned turtle.〔〔〔 Some sources treat the term "turtle" as synonymous with "capsize" or "keel over".〔〔 *〕 but most others make a distinction.〔Compare, "''Turn Turtle''. To turn over completely, with keel uppermost." "''Capsize''. To overturn or upset. Said to be derived from words meaning 'to move a barrel by turning it on head and bilge alternatively'." See also keeling over and capsize on Wiktionary.〕 Carrying too much sail or loss of control can lead to broaching "Broaching is when the boat heels too far to one side, or capsizes." While all turtlings involve a capsize, the converse is untrue. Prevention is the first priority.〔〔 〔"A seaman laboring under an undue sense of security becomes at once worth hardly half his salt." Joseph Conrad. cited in Rousmaniere at p. 19.〕 Capsizing (but not necessarily turtling) is an inherent part of dinghy sailing, and is considered to be "routine." It is not a question of ''"if"'' but a question of ''"when."''〔〔(【引用サイトリンク】title=Will I capsize? )〕 Practice capsize drills are (and should be) part of the training of every dinghy sailor.〔〔 For those who do not want the experience, a keelboat monohull has physics on its side.〔〔 (See Limit of Positive Stability.) But even yachts can capsize and turtle in extraordinary conditions, so design considerations and suitability for particular tasks, locations, weather, duration and situations are essential queries.〔〔〔〔〔〔 "Such events can overcome skill and experience"; boats need to be appropriate for foreseeable conditions.〔〔〔〔〔 It is a fundamental question of seaworthiness. Turtling commonly occurs when a boat capsizes and is not righted or attended to in time, allowing it to roll through the approximately 90 degrees of a capsize through to 180 degrees from upright.〔〔 Prevention and delay of turtling in dinghies is the highest priority〔 turtling can be catastrophic in consequences but it depends on skill, ability and athleticism, which vary greatly.〔〔 As John Rousmaniere wrote: Testing confirms the Royal Yachting Association's conclusion that "a decisive way to address entrapment is to immediately right the boat by putting weight on the centerboard" daggerboard, (or bilgeboard in a Scow).〔 His 2012 report advises that "US Sailing and other organizations should consider establishing this as doctrine." Thus, reliance on boat handling and seamanship may be misplaced.〔 Sealing masts and attaching flotation are effective preventatives for turtling of dinghys, but not widely utilized.〔〔 More certain preventatives for this includes various forms of flotation added to the tip of the mast or top of the mainsail.〔Intended for "rough weather or novice racers." (【引用サイトリンク】title=Hartley Wayfarer Mark IV ) Distances, obstacles and the likelihood of rescue are other factors that should be considered in deciding whether to prepare for the worst. As Franz Kafka, Larry McMurtry in Lonesome Dove, and Huey Lewis and the News have written: "It is better to have it and not need it, than need it and not have it."〕 These include floats (e.g., one that looks like a streamlined blimp used on Hobie 16s)〔"Easily removed for trailering or racing." 〕〔(【引用サイトリンク】title=What Should I do to Prevent Turtling )〕 or a "sail patch" a sleeve with built in flotation that fits over the top of the sail, available for example as option on the Wayfarer (dinghy) Mark IV.〔〔 Another alternative is to seal the mast, thereby increasing its buoyancy.〔 As an emergency palliative, putting flotation (''i.e.'', a spare life vest or other personal flotation device), onto the end of the mast straight away after a capsize and without delay, can forestall a turtle. Conversely, climbing onto the side of a knocked down boat can increase the likelihood of turtling, as it moves weight higher over the center of gravity, may also increase windage, and thus can effectively drive the mast downward.〔 Several devices have been patented to prevent turtling.〔 Capsizing is particularly troublesome for catamarans and trimarans, which are especially hard to right.〔〔(【引用サイトリンク】title=U.S. Patent No. 5255624 ) which includes a discussion of turtling.〕 The use of a trapeze, harness, Jackline or other tether can cause injury or death due to entrapment if a boat turtles.〔〔〔〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Turtling (sailing)」の詳細全文を読む スポンサード リンク
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