Vessel Grounded Due to Rudder Angle Transmitter Failure – Investigation Report

At 1706 on 29 April 2011, the Panama registered bulk carrier Dumun grounded while departing the port of Gladstone, Queensland. Prior to the grounding, the ship’s steering appeared to stop responding to bridge commands when the linkage between the tiller and rudder angle transmitter became detached. The steering gear continued to operate normally, but the transmitter lost its input signal and, as a result, the bridge mounted rudder angle indicator stopped working.

The bridge team assumed that the steering had failed, so the pilot ordered the main engine stopped and then started astern. However, these actions were not enough to prevent the ship from grounding

The ATSB determined that the ship’s builders did not identify that the rudder angle indicator transmitter and tiller linkage were not installed correctly. More broadly, the ATSB found that the analysis of shipping operations in Gladstone, carried out by the relevant authorities, had not appropriately considered all that could be done to prevent the grounding of a ship as a result of steering gear or main engine failure. In addition, it was found that a comprehensive safety management system had not been implemented in Gladstone with the aim of identifying, evaluating and controlling pilotage related risk.

As a result of the investigation Dumun’s shipbuilder has sent a bulletin to the owners of all ships built by the company advising that the rudder angle indicator linkage should be checked to ensure that it is correctly fitted. The company has also modified its procedures to ensure that these checks are carried out during the building of all future ships. Maritime Safety Queensland (MSQ) and its pilots have worked with Gladstone Port Corporation and terminal operators to improve ships’ readiness for departure by implementing rigorous pre-departure checks. MSQ is also in the process of developing a single pilotage safety management system covering all of the ports inwhich the organisation provides pilotage operations.

Source: ATSB