The Liberia Maritime Authority presents methods for determining rudder angular position in case of Rudder Angle Indicator System (RAIS) failure.
Background
The Australian Transport Safety Bureau (ATSB) report on the grounding of a Liberian-registered ship identified that the tracking motor of the omnidirectional rudder angle indicator burned out, causing a short circuit. This short circuit tripped the common circuit breaker in the bridge cabinet, causing all rudder angle indicators in the wheelhouse, steering gear, and engine room to lose power and stop functioning at the time of the incident.
It should be noted that while the steering and rudder angle indicator systems complied with applicable rules and regulations, neither the SOLAS regulations nor the rules of the ship’s responsible classification society mandated protection of the ship’s rudder angle indication systems against a single point of failure in power supply. Furthermore, there were no requirements for audible or visual alerts to notify the bridge team of a power failure affecting the indicators.
Following this incident, the Pilbara Ports Authority (PPA) issued a marine notice requiring that a suitably qualified and competent person stands by in the steering gear room during a ship’s transit of the Port Hedland channel.
From 1 January 2025, all capesize vessels (nominal deadweight > 120,000) entering and operating within the Port of Port Hedland are to be equipped with a minimum of one (1) Closed-Circuit Television (CCTV) rudder camera installed at the steering gear flat, positioned to clearly capture the rudder angles during maneuvering.
Recommendation
The Administration recommends shipowners, operators, masters, and crew:
- Be aware of the alternative way to determine the angular position of the rudder in case of a failure of the RAIS, i.e., “angular position of the rudder to be recognizable in the steering gear compartment and by utilizing the means of communication available between the steering gear compartment and the navigating bridge.”
- Ensure that a suitably qualified and competent person is stationed in the steering gear room during navigation in narrow channels.
- Inform bridge personnel of any other means of indicating rudder angle not associated with the main rudder angle indicators, such as one available on the autopilot console or other location.
The Administration also recommends that the Company consider modifying the power distribution system to all rudder angle indicators to provide a level of redundancy.
