Broach

A sudden, largely uncontrolled turn that leaves a vessel sharply across its intended course.

A sailing yacht may broach when overpowered while reaching or running, causing rapid heel and loss of rudder effectiveness as it turns towards the wind. A power-driven vessel can broach when overtaken or slewed by a following sea, particularly while descending a wave.

A broach does not always place the vessel exactly broadside to the waves, but it can lead to knockdown, capsize, water ingress, gear damage or people falling. Risk reduction depends on suitable speed, course, sail area and trim, active steering and anticipation of waves rather than one universal recovery action.