Tidal Stream Ship Grounds Twice in Two Days

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Summary:

On 10 June 2017, the UK registered bulk carrier Ocean Prefect grounded when approaching Ahmed Bin Rashid Port, in Umm Al Qaywayn, United Arab Emirates. The vessel was not damaged and refloated 12 hours later with tug assistance. It then anchored in safe water. On 11 June, the vessel again touched the sea bottom when entering the port, but was able to continue to its berth. However, on this occasion, three of Ocean Prefect’s ballast tanks were breached, which required the vessel to dry dock in Dubai for repair. Two harbour pilots were on board during the groundings. There was no pollution and no injuries.

Damage and repairs:

Ocean Prefect’s cargo discharge in Umm Al Qaywayn was completed on 16 June 2017. The vessel then sailed and anchored off Dubai, UAE. On 18 June, a dive inspection identified a series of splits, deep indentations and buckling of the shell plating between frames 184 and 109 on the port side. The largest split was 9100mm in length and 200mm wide. Inspection of the starboard side identified only abrasion damage to paintwork. With Lloyd’s Register’s approval, Ocean Prefect proceeded to dry dock in Dubai for repair.

Findings:

  1. The pilots had very limited local knowledge and had only previously completed two pilotage acts in the port.
  2. The effect of a tidal set was influential in both groundings.
  3. The available tidal stream data for the port was insufficient to plan the safe passage of deep draught vessels using the port’s narrow approach channel.
  4. The positions of the navigation marks used to indicate the limits of the port’s approach channel were potentially misleading.
  5. The port in Umm Al Qaywayn lacked resource and marine expertise.

Action Taken:

  1. Pilotage for vessels calling at the container and bulk terminal facility will be arranged only through the port authority.
  2. The port authority will provide navigational information to visiting vessels.
  3. Leading lights will be established in the approach channel.
  4. Vessel movements will be controlled and a port control facility will be established.
  5. A hydrographic survey of the port and its approaches will be conducted.
  6. Navigational aids will be upgraded.

Conclusions:

  1. The tidal stream in the approaches to Umm Al Qaywayn immediately before high water set to the west at a rate of up to 1kt. It was not slack as anticipated by Ocean Prefect’s master and pilots.
  2. On 10 June, neither the pilots nor the master recognised that the action taken to counter the tidal stream and steer the vessel into the dredged channel before it encountered shoal water was insufficient.
  3. On 11 June, in view of the tidal set experienced the previous day, it was logical to keep Ocean Prefect towards the eastern side of the dredged channel.
  4. The tidal stream experienced along the dredged entrance channel into Umm Al Qaywayn was variable.
  5. Pilotage was not compulsory in Umm Al Qaywayn but information on the port and its approaches was limited.
  6. The embarked pilots, although experienced elsewhere, were not fully familiar with Umm Al Qaywayn and its approaches, and had completed only two previous pilotage acts in the port.
  7. The tidal data available for Umm Al Qaywayn was limited to the predicted times and heights of high and low water and the direction and maximum rate of the flood stream close offshore.
  8. The narrowness of the dredged channel and the potential for squat limited the action that could be taken on board larger vessels to counter the effects of a tidal set and to remain within the dredged channel.
  9. The lateral posts marking the dredged channel were sited up to 50m outside the channel, which was not clear from Admiralty chart 3405 due to its scale, and was potentially misleading.
  10. Ahmed Bin Rashid Port lacked resource and marine expertise and took no responsibility for pilotage. Ocean Prefect’s pilots were permitted to operate in the port to provide competition and reduce pilotage costs for shipowners.

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Source: MAIB

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