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 capsize 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.
The Administration also recommends that the Company consider modifying the power distribution system to all rudder angle indicators to provide a level of redundancy.
