5.3.5(c) Centralized or unattended operation. Where the propulsion machinery space is intended for centralized or unattended operation (ACC, ACCU or ABCU notation), a high bilge water level alarm system is to be fitted, see 4-9-3/15.3. As a minimum, bilge valve controls are to be located above the floor grating, having regard to the time likely to be required in order to reach and operate the valves.