Relative to monohulls, it is more hazardous on multihulls, because of their inherent stability in an inverted position. When a boat is “turned over completely” it has turned turtle. Some sources treat the term “turtle” as free sailing books pdf with “capsize” or “keel over”.
While all turtlings involve a capsize, the converse is untrue. Prevention is the first priority. 90 degrees of a capsize through to 180 degrees from upright. More certain preventatives for this includes various forms of flotation added to the tip of the mast or top of the mainsail. Several devices have been patented to prevent turtling.