Turtling (sailing)

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. The term can be applied to any vessel; turning turtle is less frequent but more dangerous on ships than on smaller boats. 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).

When a boat is "turned over completely" it has turned turtle. Some sources treat the term "turtle" as synonymous with "capsize" or "keel over". but most others make a distinction. 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.

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." Practice capsize drills are (and should be) part of the training of every dinghy sailor.

For those who prefer to avoid 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.

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