69.—(a) Indicators shall be provided for all shell doors, loading doors and other closing appliances fitted to openings which if left open or not properly secured could lead to major flooding of a special category space or ro-ro cargo space.
(b)The indicator system shall be a panel at the navigating bridge consisting of a green indicator light and a red indicator light for each access opening connected to suitable switches at the opening so that the green light will be illuminated on the panel for a particular opening only when the door or other closing appliance is both closed and secured;
(c)All switches or relays shall be connected so that if the door or appliance is not fully closed or properly secured the red light on the panel will illuminate;
(d)The power supply for the indicator system shall be independent of the power supply for operating and securing the doors or closing appliances.