The German Bureau of Maritime Casualty Investigation published its findings on the allision of Northsea Rational with a quay in the River Elbe.
The incident
The Maltese-flagged chemical and products tanker NORTHSEA RATIONAL was scheduled to depart for Malmö on the morning of 25 November 2020 with a cargo of biodiesel.
The ship had taken on this cargo in Hamburg at ADM Hamburg AG’s berth at Köhlbrand.
The subsequent course of the accident is based on the account of the ship’s master and other officers involved.
The ship was made ready for sea after loading was completed. The second officer prepared the bridge in accordance with the shipping company’s specifications using a checklist. Preparations in the engine room for departure included an inspection of the steering gear. No malfunctions, leaks or other irregularities as compared to the normal condition were found.
The port pilot reached the ship at about 0940. All lines had been cast off by 1005 and the ship set sail in good visibility without tug assistance. According to the voyage data recorder (VDR), a north-west wind of 2–3 Bft prevailed at the time.
The pilot, the master and the second officer were on the bridge for the casting off manoeuvre and subsequently when the ship was in estuary mode. The latter acted as helmsman. He stood at the central console and operated the rudder manually. The pilot issued helm orders directly to the second officer. The master controlled the CPP’s pitch from the central console in accordance with the pilot’s recommendations.
The left-hand bend at Köhlbrand was passed without any complications and partly at reduced speed because diving works were taking place there. The speed was then increased again.
Köhlbrand was then left while maintaining the turn to port so as to steer the necessary course for navigating the river. At this point the tide was moving in the opposite direction. When a compass course of about 275°5 had been reached, the pilot recommended switching to autopilot6. During the switchover to autopilot, the vessel suddenly began to turn to starboard. The turn was triggered by an independent and unintended rudder movement to starboard. The ship’s speed was about 10 kts at this point. According to the master, the northern bank was about 150 m away.
An attempt was immediately made to turn the ship to port using the hand steering but she continued to turn to starboard. It became apparent that there was a malfunction in the steering gear control system.
The master set the CPP’s pitch to full astern to reduce the speed. It was clear to the master that there would be an allision with the northern bank. Accordingly, the tyfon was sounded to warn the surrounding area.
In addition, the port anchor was dropped (two shots of chain cable). This could be executed quickly because both anchors were prepared accordingly. This was dealt with by the chief mate and bosun, both of whom were still on the forecastle. Both measures reduced the impact speed. The deployment of the anchor caused a slight turn to port.
In his statement, the master concluded that the last exercise for the measures to be taken in the event of a steering gear fault had taken place five weeks earlier.
The impact with the quay wall was at an angle of about 60°. Therefore, most of the damage to the ship was on the starboard side of her bow.
Probable cause
According to the report, the cause was the described wear on a relay, which led to its failure. Accordingly, this short-term failure was the direct cause of the accident.
The failure occurred when the transfer to autopilot took place. The BSU’s expert and its investigators are of the opinion that this failure led to a strong deflection of the rudder to starboard
said BSU.
This rudder deflection caused the ship to start turning. The expert believes that the immediate return of the rudder is an indication that the relay’s operability was restored at this point.
The failure of the relay was not caused by an operating error of the crew. Rather, it was a random event and could not be influenced.
Recommendations
After the investigation of the incident, the Federal Bureau of Maritime Casualty Investigation recommends that the manufacturer of the steering gear control system, Kongsberg Maritime, adapt the current steering gear control system manuals so that safety-critical conditions during switching operations are better highlighted in the text.
EXPLORE MORE ON BSU’S ACCIDENT REPORT
