A sea anchor, used to stabilize a boat in heavy weather, anchors not to the sea floor but to the sea itself, as a kind of brake. Usually shaped like a parachute or cone, it is fed out from the ship or boat so that it fills under water; floating sea anchors intended to drag on the surface of the water have also been used. A long line (typically between ten and fifteen boat lengths) is attached to the sea anchor and the bow of the boat or ship. The sea anchor is pulled by the current, and allows the boat to ride out the storm by keeping the hull in line with the wind and perpendicular to waves. This forms the basic technique of heaving to.

Sources

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