Vessels involved in the Bourbon Dolphin disaster included the semi-submersible Transocean Rather, the Ulstein A101 Olympic Hercules, the UT 722 Highland Valour, the KMAR 808 Vidar Viking and the KMAR 404 Sea Lynx. The ships were to recover the moorings then move the rig for a couple of miles and then deploy them again.

The Transocean Rather, the Olympic Hercules and the Vidar Viking in Invergordon

PREAMBLE

In addition to the involvement of the owner of the rig, Transocean, and the charterers of the rig, Chevron, the rig move procedures and various aspects of the management of the move, including the provision of the towmasters, were in the hands of Trident Offshore an Aberdeen marine contracting company.

The Transocean Rather was provided with a chain wire combination to allow it to work in deep water, but to conform to the POSMOOR requirements for the 1100 metre (3600 feet) water depth at the location, modifications to this system were required to prevent anchor uplift in the worst of the prospective winter weather. As a consequence 900 metres of chain were added to the rig’s own 914 metres, this being deployed from the chain lockers of the attendant anchor-handlers.

Load sharing procedures had been written for the deployment, the tow vessel being released from the bridle and taking the weight of the chain just to seaward of the transition. The two ships would then run out, with the rig paying out its wire until the anchor point was reached and then the main vessel would lower away, the grapple vessel would be freed and the anchor would be put on the bottom. The grappling vessel would move on – and so on. This was an adjustment from the original procedures because the brakes on the rig’s winches had proved to be unequal to the task of restraining the wire against the weight of the chain and the pull of the vessels.

Once the primary anchors had been deployed the “main” anchor-handlers would move on to the secondary anchors. The assisting vessels could now be used to take the weight of the chain at the rig end, and once the wire was deployed they could move to a position astern of the main vessels and take some of the weight while the anchors were launched, once more to reduce the possibility of damage.

 In the event, the recovery of the anchors commenced with only the Olympic Hercules and Bourbon Dolphin on the location and so the Bourbon Dolphin recovered two of the secondary anchors, and was therefore required to run them on arrival at the new location, a task which had originally be assigned to a “main” vessel. Later the Highland Valour, the Vidar Viking and the Sea Lynx were hired, the last being the least powerful solely as a towing and grappling vessel.

On March 27 the Olympic Hercules and the Bourbon Dolphin started to recover anchors, each acting as primary and assisting vessel, until March 29 when the Bourbon Dolphin was sent off to Scrabster for a crew change. The crew change took place before dawn on March 30, and took one and a half hours. The new master had not sailed on the ship before, although it was claimed by Bourbon that his usual command the Bourbon Borgstein, was more or less the same. The leaving master said that he had told the joining master that the ship should only be used as an assisting vessel, but what-ever else was said, the hand-over could hardly have been adequate, and this was observed by the Commission. Bourbon themselves had hand-over procedures, which appear not to have been followed.

The Bourbon Dolphin returned to the field on March 30 and continued to work with the Olympic Hercules. On April 2 the Highland Valour, the Vidar Viking and the Sea Lynx arrived and the work continued. Even though the anchors were all eventually recovered there was some damage, and several J-hooks were broken. These factors, together with some winch failures and some weather downtime, meant that all the anchors were not recovered until April 8. The original plan, to lift the four primary anchors at the same time and move the whole set-up the two miles to the new location without recovering the chains, had long been abandoned, and so all the anchors were to be run from scratch.  

It may at this moment be worth describing the running of one of the anchors. Because of the winch problems at the first location it had been decided to use two ships in two parts of the operation. The primary vessel, with chain in its chain locker would take the chasing pennant from the rig and pull the end of the rig chain aboard, it would then start out on the line towards the anchor position and the rig would deploy its chain until all 900 metres of 84mm chain had been run out. A second ship would then grapple the rig chain close to the rig and the transition would take place. The assisting vessel would release the grapnel, the primary vessel would then connect up the additional chain from the chain locker and run out all 900 metres. It would then be necessary for the assisting vessel to grapple the chain astern of the primary vessel, this to allow the anchor to be launched. All of these activities are preliminary to the “load sharing” part of the job. At this point there would be 1800 metres or so of chain hanging between the stern of the ship and the fairlead of the rig. The final segment of the operation would therefore be for the ship to head for the final anchor position with the rig paying out the wire part of the mooring. Then with the ship at the anchor position it would start to lower it away, probably still moving ahead. Eventually the anchor would be on the seabed, at the correct distance from the rig, on the correct bearing.

To assist with the positioning, the rig and the ships were provided with a navigation system which showed the whole operation on a computer screen. All the ships had to do therefore was keep their image on the screen on the line until they reached the anchor position.

The mooring operation at the new location started in the morning of April 9, the ships following the process described, but before long, with worsening weather forecasts, the management decided to send three of the vessels to Lerwick to re-arrange their equipment, and in the case of the Bourbon Dolphin to exchange two twelve tonne Stevpris for two eighteen tonners.

The Bourbon Dolphin in Aberdeen shortly before the accident.

THE SEQUENCE OF EVENTS.

The writer has had access to the towmaster’s log and the rig move procedures as well as the Royal Commission report, and hence where there are disagreements between them comments are included.

April 11 2007.

0745. The three ships are back on the location and the job continues.

April 12 2007.

0242. The Olympic Hercules starts to run No 6, the penultimate anchor (The Commission chose to look in detail at the running of this anchor since it was directly opposite to No 2). The rig pays out the anchor chain.

0340 approx. The transition is carried out on the rig and the Olympic Hercules then pays out the insert chain. The vessel is being constantly set to the east by the current and during the overboarding of the anchor ends up 700 metres away from the track, despite using most of the vessel’s considerable thruster power. The Captain thinks that the current is more than 2.5 knots although this estimate is not supported by the current data obtained during the investigation. In the end, after some discussion with the rig, the mooring wire is paid out which allows the ship to gain headway and set course for the anchor drop position.

0920. The PCP (Permanent Chasing Pennant) is passed to the Bourbon Dolphin, and once it is secured the ship takes off on a course of 340 degrees in the direction of the No 2 anchor position with the rig paying out its chain.

1000. All the rig chain at No 2 anchor has been paid out, and the transition takes place.

1015. The transition at No 2 is completed (According to the towmaster’s log).

1130. The Vidar Viking, which had been assisting with No 6, is instructed to de-tension its workwire and leave the field (The Commission took this instruction to be an indication of an unwise attempt on the part of the operator to save money).

1200. On the Bourbon Dolphin the watch is changed. The Captain and one of the First Officers are relieved by the Chief Mate and the other First Officer, and it seems likely that the Chief Mate, who had limited experience in the driver’s seat, is relying entirely on the joystick, and therefore solely on thruster power to get the ship back on the line.

1215. The Bourbon Dolphin resumes its course in the direction of the anchor position paying out the insert chain, probably once the insert chain has been connected up (The Commission assumes, probably incorrectly that the rig chain had not been completely deployed until 1215).

1233. No 6 anchor is landed on the seabed by the Olympic Hercules. By now the wind speed is about 30 knots, and the significant wave height about 3.5 metres. These conditions were generally agreed by everyone who was on the location, although there is some disagreement about the strength of the current.

1300-1400. The thrusters on the Bourbon Dolphin are overheating and attempts are made to cool one with a pressure hose.

1400. The Bourbon Dolphin has paid out the insert chain keeping on track, but now 1100 metres (3600 feet) from the rig it seemed to falter and start to drift off to starboard. At some time after this the Bourbon Dolphin asks for assistance to get back on track, and the Highland Valour is assigned to grapple for the chain astern of it, in order to take some of the weight.

1500. The Highland Valour starts to grapple for the anchor chain astern of the Bourbon Dolphin.

1610. The Highland Valour’s grapnel seems to have made contact with the chain, and within minutes there is a very close approach between the two ships. Probably the Bourbon Dolphin drifts astern towards the Highland Valour, and in order to avoid collision the latter quickly lowers away the workwire, and disengages the grapnel from the chain. The rig issues an instruction that no further attempts to grapple should take place and the log entry states that “Both vessels instructed to move away from No 3”. (The Commission took it as an indication of poor communication that neither the OIM of the rig, the man formally in charge of the rig move, or the Barge Supervisor the senior marine person, were informed of the near miss.)

1620 approx. The Captain of the Bourbon Dolphin returns to the Bridge and it appears that he takes over in the driver’s seat, and the Chief Mate starts to transfer ballast to correct a list of about five degrees to port. The ship wants the rig to start to run out its wire, but as an alternative the towmaster proposes that the ship should run out its workwire, which is still connected to the chain.

1640. The Bourbon Dolphin is nearly 950 metres (3100 feet) to the east of the line and is getting close to the No 3 anchor wire.  The anchor chain is leading off to port between the starboard towing pins, and is tight up against the inner pin, apparently preventing the bow from turning to port. The towmaster may have requested that this pin be lowered to allow the chain to move to port (However he denied this. The Commission considered that in some way the possibility entered the thinking of the bridge team on the Bourbon Dolphin).

1700 approx. The inner pin of the starboard set is lowered. The witnesses testified that they “saw the chain smack over against the port outer pin, and that they heard a loud bang”.

1705 approx. The ship lists heavily to port and then, after about 15 seconds returns to upright. The Chief Engineer warns the Bridge that the starboard engine has stopped, and the surviving First Officer apparently sees the winch tension increase to 330 tonnes.

1708. The ship lists again. The First Officer activates the winch emergency release and leaves the bridge. The ship continues to list to port and then rolls over.

After the ship capsized the OIM on the rig immediately raised the alarm, and in accordance with the communications documentation for the contract, the managements of both Transocean and Chevron were informed within minutes. The crew members who had managed to escape from the ship were now either in the sea or had climbed onto a rescue float or a container. The Highland Valour approached the casualty and launched its MOB boat at 1730.  It immediately went to the container on which three of the survivors were, and recovered them to the ship. The ERRV (Emergency Response and Rescue Vessel) Viking Victory which was assigned to the Transocean Rather launched its two fast rescue craft and picked up the Cook, who was floating in the sea. The FRCs also picked up the three survivors who were on a rescue float, as well as the body of the Chief Mate. All the vessels then began to search for survivors, although it was not until 1839 that the numbers on board were confirmed as being 15.

In the hours of darkness the search continued, although the helicopters were detached to take the survivors to the Shetland Islands, to bring out navy divers and to start to downman the rig. The Grampian Frontier arrived on the location to provide ROV services and to act as a base for the divers. By 1545 on the following day the Coastguard informed the rig that the nature of the operation had changed from a rescue to a salvage operation. Eight of the crew of the vessel had died including the Captain and his fifteen year old son, who had been on board undertaking work experience.

The Commission went on to review the salvage activities, which themselves were problematical with a divergence of views as to what should be done, when, and how, but they are not reported on further in this summary.

THE INVESTIGATION.

The Royal Commission report extended to 208 pages without appendices, and may have been hampered by a lack of anchor-handling expertise amongst the Commission members.

All aspects of the operation up to and after the capsize were investigated in depth by the Commission, and also by Transocean, the owners of the rig, and by Chevron the operator, who hired the ships. The Commission discovered that the Bourbon Dolphin had had a previous incident where it had taken a serious list when an anchor had moved on the deck, but that this had not been reported. It discovered that the Stability Book, which, although it was supposed to be readily accessible to the master, extended to more than 500 pages, only conformed with the stability criteria because a smaller winch than that installed was used, and calculations had been carried out with the work wire theoretically retained between the inner towing pins, a very unlikely situation. The Stability Book also failed to provide instructions on the use of the stability tanks, which was prohibited during anchor-handling, although the experts determined that in fact the stability tanks had been in use. The examples of stability conditions in the book also required more than 500 tonnes of fuel to be carried at all times, limiting the theoretical operating period for the ship to a few days. The master who had been relieved on at the crew change testified that on two occasions he had requested clarification on stability from his company, but that none had been forthcoming. The Stability Book, despite its defects had been approved by the Norwegian Maritime Directorate.

The moment of the capsize had been caught on the mobile phone of the Transocean Rather crane operator, and the accompanying soundtrack, in broad Scottish and full of old English expletives, is a chilling reminder of the distress of the event. While the soundtrack was clear it was almost impossible to see the ship, but despite this the Commission chose to rely on it for possibly its most major finding. This was that the angle of departure of the chain was between 40 and 60 degrees from aft, and that while it was unlikely that the tension reached the 330 tonnes claimed by the First Officer, a tension of 200 tonnes if the angle had been 40 degrees, or 180 tonnes if the angle had been 60 degrees would have resulted in the margin of stability being overcome.

Any investigation into an operation as complex as the one being carried out by the Transocean Rather would be bound to find many defects in the manner in which the activity was being carried out. This is the way of the world, and sure enough the Commission made a large number of recommendations which were directed at the IMO, the NMD, DNV, Bourbon, Chevron and Transocean and some to the industry in general, the most important of which might be the formal requirement for maximum forces to be applied to moorings at different departure angles from the anchor-handlers’ sterns. Readers should access the Royal Commission report to view the rest, most of which would seem to be common sense, but we have to face it, often not actioned by those moving oil rigs.

AUTHOR’S COMMENT

In the very first session where witness statements were taken, the First Officer testified that on departure from Lerwick on April 10, he had been told to write the GM in the logbook and that the figure had been 0.29 metres. This would have raised concerns in the mind of an experienced deck officer who was aware of the work that the ship was about to carry out, but the First Officer’s experience was very limited. In the event none of the stability experts could replicate this condition no matter how they loaded the ship, so one assumes that it was a figure picked out of the air by either the Chief Mate or the Captain. This in turn would suggest that the stability computer had not been consulted prior to departure, although this point is not raised by the Commission.

Much was made in both the Commission report and in the media about whether the Bourbon Dolphin was a “main vessel” or an “assisting vessel”. And material to this distinction is the fact that before the vessels left Aberdeen they were briefed on the operation by the Trident Offshore Superintendent. According to the report there was a disagreement between him and the Captain of the Bourbon Dolphin about the content of this briefing. The Captain claimed that he had disputed the capability of the Bourbon Dolphin to run anchors in the depths of water where the job was to take place, and  with the forces envisaged. The Trident man said that no such discussion had taken place, and that it was going to be necessary for every ship to run at least one anchor. This is obvious if the rig move procedures are read. Looking back it seems to have been optimism on the part of Bourbon’s marketing department, an acceptance of the specification by Chevron, and the fact that no-one could have envisaged the disaster to come.

The activities out on the location were documented in the Commission report but it is possible that the correct conclusions were not arrived at, or even the activities undertaken correctly assessed.

The activities which related to the Highland Valour, which briefly grappled No 2 anchor chain astern of the Bourbon Dolphin,  came in for considerable scrutiny. The testimony regarding this event is confused, and much was made of it by the press after the witnesses had described it, however it seems most likely that the Bourbon Dolphin drifted astern towards the Highland Valour, and in order to avoid collision the latter quickly lowered away the workwire, and disengaged the grapnel from the chain. It may be that as soon as the Highland Valour appeared to have reduced the  weight on the chain, that the driver on the Bourbon Dolphin reduced power on the main engines, and hence the rapid change in position.

However, regardless of the operational and manoeuvring failings out on the location it seems likely that the problems with the ship had their origins much further back in its life. The manipulation of the stability manual and the failings of Bourbon to address the resulting problems would have had an effect, particularly if the master was unfamiliar with the ship. To many it must therefore seems pretty clear that if the stability of the vessel had been paramount in the minds of the crew, and if they had been provided with the correct information presented in the appropriate way, there would not have been a disaster. Bourbon’s formal procedures should have ensured that this happened, but even when it was evident that maintaining the stability of the Bourbon Dolphin would require more that the usual level of attention, nothing was done to ensure that the master who joined on March 30 was fully informed. If he had been it is possible that the ship might have been fuelled in Scrabster on March 30 and in Lerwick on April 10.  Whether No 2 anchor would have been run on April 12, or whether contact with No 3 anchor would have been avoided remains debatable, but it is pretty certain that the vessel would have remained upright.

 The accident resulted in action being taken in advance of the findings of the Commission by several bodies. Stability guidance for anchor-handling was issued by the IMO, and the NMD and in UK the Marine Safety Forum set up committees to look at means of auditing vessels before hire, means of improving rig move procedures and a format for rig move risk assessments. Whether all these activities and the fulfilment of the recommendations, where appropriate, resulted in a genuine reduction in the risks involved in deepwater anchor-handling remains, in the view of the author, debatable. Towmasters remained, in many cases, reluctant to take control of the activities of the ships involved in rig moves, on the assumption that the shipmasters would know enough about the job, and the formats for the pre-move risk assessments did not often provide an opportunity for discussion about the process. Essentially everyone wanted to carry on just as they had before.

The Norwegian Royal Commission seemed reluctant to apportion blame particularly to their own regulatory bodies and commercial organisations, focusing as they did on the lack of risk assessment undertaken by those carrying out the task. But had they undertaken such a process the boxes for the Bourbon Dolphin would all have been ticked. It was constructed by the most experienced offshore vessel designers in the world, Ulsteins, and the Stability Manual had been approved by the Norwegian Maritime Directorate. What more could one ask?

Subsequent to the disaster Bourbon was fined for not following their own procedures for hand-overs, and the UK HSE issued “Improvement Notices” to Transocean, Chevron and Trident. The notices were issued under the “Health and Safety at Work etc Act 1974” (not the Safety Case Regulations) in that essentially a safe place of work had not been provided. The companies appealed against the notices and so the HSE chose to take them to court. However, outside the court on the day the hearing was due to commence the HSE withdrew the notices. In the view of the writer it is possible that the rig was not even an offshore installation within the meaning of the Safety Case Regulations at the time of the accident, since technically it was not actually moored.


 
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