"...Material Condition Zebra..."

10-9???

Condition XRAY provides the least watertight integrity and the greatest ease of access throughout the ship. It is set when the threat to the ship is minimal. Condition XRAY is set during working hours when the ship is in port and there is no danger of attack or from weather. The minimum degree of tightness permitted on an operational ship is condition XRAY. When condition XRAY is set, all fittings marked with a black X are closed.

Condition YOKE provides a greater degree of watertight integrity than condition XRAY, but to a lesser degree than the maximum condition. YOKE is normally set at sea and in port during wartime. When Condition Yoke is set, all fittings marked with black Xs and Ys, Circle X and Circle Y are closed. A modified condition YOKE is sometimes used at sea when cruising independently in good weather and calm seas and in port in peacetime. In the modified condition, YOKE fittings above the waterline are left open to improve ventilation and habitability. All other XRAY and YOKE fittings are closed.

Condition ZEBRA provides the greatest degree of subdivision and water-tight integrity to the ship. It is the maximum state of readiness for the ship's survivability system. Condition ZEBRA is set: Immediately and automatically when general quarters is sounded; When entering or leaving port in wartime; To localize damage and control fire and flooding when the crew is not at general quarters; and At any time the CO deems the maximum condition of survivability should be set. When condition ZEBRA is set, all fittings marked with black Xs and Ys, Circle X, Circle Y, Circle Z, red Zs and DOG Zs are closed.