Report on the investigation of the groundings of Ocean Prefect - Umm Al Qaywayn, United Arab Emirates (II)




2.1 AIM

The purpose of the analysis is to determine the contributory causes and circumstances of the accident as a basis for making recommendations to prevent similar accidents occurring in the future.



Ocean Prefect was set to the west of the dredged channel at the entrance to Umm Al Qaywayn by the tidal stream. On passing between No.1 and No.2 buoys at 1254, the pilot steadied the vessel on a heading of 167˚, the channel’s axis, but it was immediately set to the west. At 1258, AIS data shows that although the vessel was heading 164˚, it was making good a course of 175˚and was about 50m to the west of the dredged channel (Figure 4). To have such an effect, the tidal stream must have been setting to the west at a rate of up to 1kt.

That the pilot initially steadied Ocean Prefect on the channel axis of 167˚ indicates that he had not anticipated a tidal set. His later heading adjustments to 165˚ at 1256:10 and to163˚ at 1257:26, which were only very minor alterations, and his enquiry regarding a gyro error, also indicate that he had not fully appreciated the cause or the extent of the set experienced. The pilot’s perspective was influenced by an expectation that the tidal stream would be slack, as the entry was within 30 minutes of the predicted time of high water and he had detected only a slight set during the outbound passage on board San Nicolas. Consequently, his focus was on being able to stop the vessel in readiness for berthing, which is shown by the reduction from ‘slow ahead’ to ‘dead slow ahead’ at 1256.

It was not until 1258, following discussion with Ocean Prefect’s master about the set and being informed by the second officer that the course over the ground was 174˚, that the pilot took more positive action. However, although he adjusted the vessel’s heading to 155˚ followed by an increase in engine speed to ‘slow ahead’, Ocean Prefect remained between 50m and 75m to the west of the dredged channel. This does not appear to have been registered by the pilot, who was navigating solely by eye, or by the master, possibly because Ocean Prefect’s bow was now heading between No.3 and No.4 lateral posts (Figure 9).



Figure 5 shows that Ocean Prefect’s track after passing the lateral buoys until No.3 and No.4 buoys was largely as intended. The differences between the vessel’s heading and its course over the ground indicate that a westerly tidal set at a rate of up to 1kt was again experienced. However, the tidal stream had been anticipated and the headings steered countered the tidal set and Ocean Prefect remained within the channel.

However, the tidal set diminished soon after Ocean Prefect passed No.4 post at 1339. This was not anticipated or noticed by the master, or the pilots, and the bulk carrier’s heading remained at least 1˚ to the east of the channel’s axis of 167˚ until the vessel encroached onto the eastern limit of the dredged channel and grounded at about 1342. In view of the vessel’s position, it is almost certain that it struck into the side of the dredged channel, but this cannot be confirmed without reference to up to date survey data of the area.


2.4.1 Passage plan
Neither the master nor the second officer had previously visited Umm Al Qaywayn and had to rely solely on the onboard charts and publications to plan the passage into the port. At first glance, the entry via the dredged channel was straightforward as the channel was marked and required only one significant course alteration.

However, the channel was only 100m wide and 10m deep, and for larger vessels such as Ocean Prefect, with a beam of over 32m and a draught over 9m, there was little margin for error. Consequently, the master’s arrangement of having a pilot to assist with the entry, although a usual practice, was a necessary precaution on this occasion. Given the navigational constraints, the need for tug assistance to berth and the limited information available, it would have been potentially unsafe to attempt entry without one.

2.4.2 10 June
After the pilots boarded Ocean Prefect on 10 June, the master and pilot exchange appears to have been clear and comprehensive and completed well before the vessel entered the dredged channel. That the pilots came across to the master as both confident and competent during the exchange, could only have increased his level of trust in them. Such trust might have been less forthcoming had the master known that the pilots had completed their first pilotage act on board San Nicolas and Ocean Prefect’s entry was their second.

Nonetheless, it is evident from the master’s interventions regarding the vessel’s set to the west soon after it had passed between No.1 and No.2 buoys, and the second officer’s provision of radar information, that Ocean Prefect’s bridge team did not allow the pilots to act in isolation. The master monitored the vessel’s movement closely and continued to challenge the pilot about the set until the vessel’s heading was altered to 155˚. In this respect, the master’s action accorded with the IMO and ICS guidance (paragraph 1.8). That he did not intervene and take the conn before the vessel grounded, which would have been an appropriate action in accordance with the vessel’s SMS (paragraph 1.4.2), was because the pilot’s actions to steer the vessel back into the dredged channel appeared to have been sufficient (Figure 9).

2.4.3 11 June
Ocean Prefect’s master’s trust and confidence in the pilots would have been shaken following the grounding on 10 June and a more cautious approach to the second attempt at entry was warranted. Therefore, from the master’s perspective, keeping the vessel on the eastern limit of the channel on 11 June would have seemed an appropriate action to take. The conditions were identical, and it was logical to assume that a similar tidal set would again be an influence.

A fundamental contribution that pilots are expected to make to vessel safety is their detailed knowledge of a port’s environment and operations. In this case, the embarked pilots, although experienced elsewhere, were not fully familiar with Umm Al Qaywayn and its approaches. They had not been given access to recent survey data, their survey of the dredged channel and the tidal streams was very limited and their only previous acts of pilotage in Umm Al Qaywayn had been on board San Nicolas, immediately before embarking on board Ocean Prefect. In addition to their lack of familiarity with the variability of the tidal stream, that more positive action was not taken on 10 June to steer the vessel into the dredged channel, indicates that the pilots also did not appreciate the extent of the shoal waters to the north of No.3 and No.4 lateral posts or have any mechanisms, such as a clearing range to ensure the vessel kept clear of them.


Other than the predicted times of high and low water, tidal information for Umm Al Qaywayn was limited to the tidal stream arrow shown on Admiralty chart 3405 and the reference to a westerly flood stream in the Sailing Directions. Although the information regarding the direction and rate of the maximum flood might have been correct, the absence of comprehensive tidal stream data in the area increases the difficulty in planning and executing a passage into and from Umm Al Qaywayn.

With an axis of 167˚/347˚ between the lateral buoys and No.3 and No.4 posts, the dredged channel runs almost perpendicular to the prevailing tidal stream. Therefore, the tidal stream’s effect on transiting vessels is potentially significant. Although this is mitigated to some degree by only allowing the movement of larger vessels around high water, when the tidal stream can usually be expected to be slack, the circumstances of both of Ocean Prefect’s groundings indicate that this is not always the case. The grounding on 11 June also indicates that the rates and directions of the tidal stream vary at different points along the channel.

The importance of accurate tidal stream data in the approaches to Umm Al Qaywayn is increased by the narrowness and depth of the dredged channel, the length and breadth of larger vessels and their speed restrictions due to squat. As the channel is only 100m wide, the extent to which a vessel can safely deviate from the base axis of 167˚/347˚ is determined by its length and its position relative to the channel’s centre. During Ocean Prefect’s entry on 10 June, at a speed of 4kts, the vessel would have had to steer approximately 152˚ to counter the 1kt tidal stream and make good a course of 167˚. As a result, the vessel’s extremities would have been perilously close the channel’s limits (Figure 10). Consequently, for large, deep draught vessels, slack or near slack water is a prerequisite of safe passage.




The use of lateral posts to mark much of Umm Al Qaywayn’s approach channel is usual in areas not suited to buoyage. In this case, the distances between the lateral marks (1290m from the gate buoys and No.3 and No.4 posts, and 955m from No.3 post to No.5 posts) were sufficiently short for the marks to provide a visual indication of a vessel’s position throughout a transit. However, that the posts were sited up to 50m outside the channel, which is not clear from Admiralty chart 3405 due to its scale, was potentially misleading. On 11 June 2017, it is highly likely that when Ocean Prefect passed No.4 post, the master was under the impression that the vessel was not yet on the eastern limit of the safe water.



Ahmed Bin Rashid Port is a small port, and its lack of resource and the absence of marine expertise had resulted in the port’s management taking little interest in the safe passage of visiting vessels. This was particularly evidenced by its approach to pilotage, for which it did not accept any responsibility. Consequently, the Amasco pilots, who had very limited local knowledge, were permitted to operate in the port to appease local agents by facilitating competition and bringing down pilotage costs for shipowners. The port also did not even provide the Amasco pilots with up to date survey data.

In many parts of the world, port authorities are expected to provide visiting vessels with the information necessary to ensure their safe passage within their ports. In this case, a lack of comprehensive tidal stream and up to date survey data restricted the ability of Ocean Prefect’s master and second officer to plan the vessel’s passage along the dredged channel. The tidal stream set the vessel across the dredged channel in a manner that could not be anticipated from the available information and the positions of the lateral posts in relation to the channel’s limits were potentially misleading.

In view of these factors, and that the use of a local pilot is essential for the safe passage of larger vessels such as Ocean Prefect, a more structured approach to pilot authorisation and the provision of tidal stream data and accurate visual references in the dredged channel, such as port entry marks, warrants consideration.




  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. [2.2, 2.3 and 2.6]
  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. [2.2]
  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. [2.3 and 2.4.3]
  4. The tidal stream experienced along the dredged entrance channel into Umm Al Qaywayn was variable. [2.3 and 2.6]
  5. Pilotage was not compulsory in Umm Al Qaywayn but information on the port and its approaches was limited. [2.4.1]
  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. [2.5]
  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. [2.6]
  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. [2.6]
  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. [2.7]
  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. [2.8]




4.1.1 MAIB
The MAIB has:
On 7 December 2017, presented the safety issues identified in Ocean Prefect’s groundings to the Director of Maritime Transport Affairs of the UAE Federal Transport Authority (FTA).

4.1.2 Actions taken by other organisations

The Government of Umm Al Qaywayn has:
In November 2017, awarded a concession to the Hong Kong based port operators, Hutchison Ports, to operate the container and bulk terminal facility at Ahmed Bin Rashid Port in Umm Al Qaywayn (UAQ).

The Port Authority has:
Agreed with the UAE Transport Authority that:
- Pilotage for vessels calling at the container and bulk terminal facility will be arranged only through the port authority.
- The port authority will provide navigational information to visiting vessels.
- Leading lights will be established in the approach channel.
- Vessel movements will be controlled and a port control facility will be established.
- A hydrographic survey of the port and its approaches will be conducted.
- Navigational aids will be upgraded.

V. Ships (Asia) Private Limited has:
Issued a safety bulletin detailing the circumstances of Ocean Prefect’s groundings in Umm Al Qaywayn, which included the following lessons:
- The master / Bridge Team must be aware that the Pilot orders are for consideration and where appropriate, they should challenge the Pilot as required to ensure the safety of the vessel. The bridge team must remain alert to the vessel’s passage during pilotage and not be lulled into a false sense of security that the pilot’s actions are failsafe.

- Chart data for harbour approaches and for critical areas of navigation have to be taken as accurate. However, consideration should be given to local port conditions where silting or other natural phenomenon’s are known to exist which affects the accuracy of the chart data. Extra caution is to be exercised when transiting such areas and this is where the advice of the pilot must be sought.
- When calling at the port of Umm Al Qaywayn, Master pilot exchange should discuss this issue. [sic]






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