Whilst the vessel was making an approach to the berth, the main engine did not start when requiring an astern movement. Eventually after a couple of attempts the main engine was successfully started. After investigation it was revealed that one of the two starter air bottles was closed, and the air pressure in the single bottle was not enough to start the main engine. Moreover, engine staff had not monitored the air pressure at all times and therefore had not opened the second bottle in a timely manner. Causal factors: Incorrect use of equipment or machinery; lack of knowledge and leadership with requirements/ guidelines not followed.
Preventative action: The matter was discussed with attention focused on the proper preparation of the main engine. If a bottle valve is kept shut then the duty engineer must monitor the pressure at all times and be ready to open the second bottle in a timely manner. The master should receive proper information from the chief engineer about the position of the interconnection of the air bottle valve. In addition, the master was advised to be more careful when manoeuvring in those waters. The vessel was maintaining a speed of 4.5 knots, with a strong current favouring the vessel, when the pilot gave an astern movement instruction. As the engine speed was higher than the minimum revolutions (rpm) required for the engine to be started, the air brake system was used. In this process the air bottle pressure quickly reduced. When the spare bottle was opened, the astern kick was effective and there were no further problems.
Lesson Learned: The engine staff should be very watchful and either keep both bottles ‘open’ or be in a position to quickly open the balancing valve.
Best practice is to test the engine astern before entry into port. The Bridge should ensure the Engine Room pre-arrival /pre-departure checks are complete. The key issue is to know the volume of the air tanks and the capacity of the compressors. Engineers should know the number of starts remaining. Consideration on the adequacy of the available starter air must be made during the design phase of the ship.