Grounding of the Tassos N

Summary

At 0500 on 10 January 1997, the 39,630 tonne Cypriot flag bulk carrier Tassos N departed the Alcoa wharf at Kwinana W.A., bound for Ferndale in the USA with a cargo of 37,775 tonnes of alumina. The weather was fine and calm and the visibility good. With a Fremantle Pilot on board, the ship safely negotiated the Calista Channel and then the Stirling Channel.

As it entered the Parmelia channel, however, a steering gear fault occurred which resulted in the ship not responding properly to the movements of the helm. The ship's head swung either side of the intended track. As the Pilot attempted to arrest the swing, the bows swung sharply to starboard. The Master switched from No.1 to No.2 steering systems but then, seeing no response from No.2, he immediately switched back to No.1. In spite of the Pilot's helm and engine orders, and dropping the port anchor, the ship grounded in the channel on a heading of 032 with 'L' beacon abeam and only 30 metres from the bridge.

The vessel had grounded only forward and was refloated later that day with the aid of tugs and a change of trim through ballasting by the stern. Damage was confined to the paintwork on the ship's bottom.

The incident was investigated by the Marine Incident Investigation Unit under the provisions of the Navigation (Marine Casualty) Regulations.

Conclusions

These conclusions identify the different factors which contributed to the circumstances and causes of the incident and should not be read as apportioning blame or liability to any particular organisation or individual.

1. Tassos N grounded as a direct result of the failure of the steering gear.
2. The steering gear failed following the perishing and breaking-up of the rubber dust seal within an actuating solenoid on the servo-control hydraulic power unit. As a consequence of this failure, small pieces of rubber jammed the movement of the solenoid causing the failure of No.1 steering system.
3. It is specifically mentioned in the manufacturer's manual, relating to the servo-control hydraulic power unit, that regular inspection or maintenance of the power unit, of which the solenoid was a component, is not necessary.
4. On account of the short time available following the steering gear failure, neither the Master nor the Pilot could have taken action, beyond the measures which were taken, to avoid the grounding.
5. Although the Master changed over steering systems to the No.2 (stand-by) system at the steering console and then changed back to the faulty system, the time available was such that the grounding was inevitable, even had he realised that No.2 system was operational.
6. The Master and other members of the ship's complement were showing signs of fatigue both before and after the grounding. It is not considered, however, that fatigue was a contributing factor in this incident.