16. OTHER IMPORTANT CONSIDERATIONS

Safety of Life

16.1   The entire operation was completed with no loss of life or serious injury to any person involved. Considering some of the appalling conditions experienced over the six days and nights of the salvage operation, this welcome conclusion was a fair reflection of the professionalism and good fortune of all directly involved. However, some concern must be expressed about the potential dangers generated by the numbers of persons who were allowed to remain on board the casualty, particularly at the time of its initial evacuation during the night of Saturday/Sunday.

16.2   In the hours after the vessel's initial grounding, and subsequent re-anchoring, a number of people boarded who had an interest in the anticipated salvage operation but no direct role to play in its execution. These persons boarded a casualty which was known to be seriously damaged, listing and unable to move to a position of greater safety. No thought appeared to have been given to whether sufficient life saving equipment was on board for these additional persons in the event of her condition deteriorating further. A vessel, even when in sound structural condition, before proceeding to sea is required to have sufficient life saving equipment for all those on board. It is not clear why this principle was overlooked in this incident when the vessel was in a far from sound condition. Indeed, this point was clearly demonstrated during the evacuation of Saturday/Sunday night when many of those evacuated were ill equipped for a rescue operation in such appalling conditions. Although it is accepted that this problem was probably compounded by the casualty's proximity to land and the ease of access so afforded, it is considered essential for the safety of all involved that the owners and/or salvors of casualties take on the role of controlling and, if necessary severely limiting, the number of persons boarding a casualty who are not essential to the immediate task in hand.

Role of Other Parties

16.3   It is notable that many individuals made contributions to the overall shipboard operation to salvage SEA EMPRESS, a significant number of whom were not members of the co-salvors' consortium and had no direct responsibility for the execution of the salvage operation. These included surveyors, pilots, MPCU advisers, etc. Whilst the primary role of these individuals could be considered as one of observing, reporting and possibly advising, almost by definition some of these persons had significant marine experience which was of value during an operation of this nature. Almost inevitably these persons took on a hands-on role in the operations, often without being requested to so do, because they saw a need for a task to be performed.

16.4   If it is accepted that all of the above mentioned individuals had a legitimate reason to be on board the casualty in order to perform their primary role, the practical contribution they made must be seen to have been of value to the operation. However, the number of such persons was significant in relation to the number of staff working directly for the co-salvors' consortium, sufficient indeed to raise questions on two matters of concern, one of which has already been addressed in the above conclusions on safety of life.

16.5   The salvors were well used to managing their own groups of staff and had effective communications within these groups. However, communications to others on board were, due to the numbers involved, somewhat less effective. This is no serious reflection on the workings of the salvors, and was probably due to them being unfamiliar with such a large number of supernumeraries being on board a casualty and involved with operations. But it did result in many persons on board feeling that they were unsure of who was in charge. Recognising that each of these supernumeraries had a counterpart ashore to whom he reported, either in the form of an individual or an organisation, any deficiency in communications on board the casualty was amplified, possibly many times over. Again this compounded any sense of confusion and feeling of being ill-informed of developments on the part of shore personnel and organisations.

16.6   For the above mentioned reasons of safety and clarity of communications, some monitoring and control of the number of persons on board a casualty is seen to be important. It is accepted that each casualty will generate its own demands for numbers of personnel, that certain individuals may have a statutory right to be on board and that no figure can be stipulated as the optimum or ceiling. However, prudence would suggest that each owner and salvor involved with a casualty should take into consideration the problems highlighted here when exercising this control.

Media Relations

16.7   The logistical advantages to the salvage operation of having this incident occur close to land and within a harbour area has already been mentioned. A corollary of this situation was that all parts of the incident were easily observable by all, particularly the media. It is understandable that in an incident of this nature where dramatic events may sometimes occur the desire for knowledge by the public should be satisfied. However, media interest can so easily develop into media pressure, even unintentionally, and it is a strong minded person indeed who, when the subject of such pressure, can claim that their decisions and actions are totally unaffected by its presence.

16.8   It should be made very clear that no person or organisation involved in this salvage has formally made the claim that media pressure caused them to make decisions which they would not otherwise have made. Any evidence which indicates that the media may have influenced the decision making processes is thus purely anecdotal. Notwithstanding the reluctance of any party to admit media pressure was significant, it is considered important that organisations involved in an operation of this nature should have staff available to supply the legitimate demands of the media without removing technical personnel from their primary tasks. Clear evidence is available which shows that key personnel from MPCU were withdrawn from vital technical roles, during the salvage operations, to handle the media. Sections 17.8 to 17.17 of the National Contingency Plan sets out the use of the Department of Transport's Press Office for this purpose and the plan includes a requirement that senior technical staff shall give press conferences, as required. This is sensible and correct, however a specially appointed technical member of staff from MPCU should be designated solely to this task leaving the other members of the team to concentrate on their specific roles.

17. LIGHTENING TONNAGE

17.1   At an early stage of the salvage operation one of the options considered was a ship-to-ship lightening operation to be undertaken. Indeed, for much of the incident this option was the primary objective of the salvors.

17.2   One of the factors which influences the consideration of any vessel for lightening duties during a salvage operation is geographical location. The greater the time required by the vessel to reach the scene of the salvage operations the less attractive that vessel becomes. Should a suitable vessel, or vessels, be operating in the area of the casualty then they could be of great value to a salvor. However, the fact that a vessel is operating implies that it is operating commercially and therefore subject to commercial restraints which may generate further difficulties.

17.3   Also to lighten significantly a vessel of the size of SEA EMPRESS requires the services of another tanker having a capacity related to the amount of cargo which needs to be transferred. To remove for example 30,000 tonnes using only a tanker of 3,000 tonnes would be a time consuming series of shuttle type operations. A preferable method would be to employ a tanker, or tankers, which could complete the total operation in one or two trips. It would be unreasonable to expect any salvor to have ready for immediate use a tanker of this size therefore it is necessary for the salvor to approach an owner of a vessel in service.

17.4    Should the manager of a suitably sized tanker be willing for his vessel to be employed in an operation of this type, on a normal commercial or charter basis, he may well be constrained by existing commercial commitments. To ignore such obligations would normally expose the vessel's manager to substantial financial penalties for breach of contract or charter, together with possible loss of reputation. In order to renegotiate their commitments a vessel's manager would require a significant time, even if such rearrangements were possible. A ship-to-ship transfer operation, being significantly different from the usual operation of a vessel, may well also require renegotiation of the vessel's insurance arrangements. All these negotiations would require time which may not readily be available during periods which are outside normal office hours.

17.5   There are two mechanisms which are presently available for incidents in UK waters which have the objective of overcoming the problems mentioned above. These are the International Salvage Union Award Sharing Sub Contract under LOF95 or a form of intervention by the Government.

17.6   One of the primary objectives of the LOF is to enable operations related to salvage to be commenced without any of the delay which may be caused by the negotiation of a commercial contract. Any negotiations which may be required will take place after the conclusion of the salvage operation and any financial settlement be made by arbitration. Should the manager of a tanker, who may be considering offering his vessel for a lightening operation as part of a salvage, be able to take part as a co-salvor or on a salvage sub-contract, then the LOF offers a mechanism whereby he may be able to claim financial compensation for commercial losses suffered as a direct result. Should the vessel's manager fail to take part under these conditions he would necessarily need to perform the required negotiations before the commencement of the transhipping operation, a time consuming process which could delay the commencement of any transhipping operation.

17.7   Two tankers were identified for lightening purposes in the SEA EMPRESS salvage. STAR BERGEN, 31,502 dwt, which is managed by Texaco, the owners of the SEA EMPRESS cargo, was chartered successfully by the salvors during Friday 16 February on a commercial charter. However the vessel was alongside in Milford Haven loading a cargo. This cargo had to be discharged ashore and she was not available until 0600 hrs on Saturday. The other vessel was WHITCREST, 3,429 dwt, also under operational control of Texaco. This particular vessel, whilst smaller than STAR BERGEN, had the advantage of having self-priming cargo pumps which would enable cargo to be transferred from SEA EMPRESS without the use of the casualty's pumps. Vessels with this type of pump are not common.

17.8   Another tanker, TILLERMAN 12,800 dwt, was identified. The managers of TILLERMAN embarked on the process of negotiating a commercial contract, with agents acting on behalf of the salvors, during Sunday 18 February. These negotiations continued until SEA EMPRESS berthed on the evening of Wednesday 21 February, without reaching a conclusion.

17.9    The delay in the above negotiating process was recognised by the officials of MPCU. The managers of TILLERMAN were contacted by telephone, late on Tuesday 20 February, by an official from MPCU indicating that the Government would underwrite any costs which may be generated by taking the vessel away from her planned commercial programme. Shortly afterwards, at 0145 hrs on 21 February, TILLERMAN was called to a berth to load its planned cargo. At this stage the managers of TILLERMAN withdrew the vessel from commercial operations in order to stand by to assist with a possible lightening operation.

17.10   The powers of intervention under Section 137 of the Merchant Shipping Act 1995, which may be exercised on behalf of the Secretary of State by MPCU, would appear not to cover any vessel other than the vessel which is the casualty or is likely to cause pollution. MPCU were thus, in this instance, not exercising these powers of intervention but were enabling the managers of TILLERMAN to assist in any lightening operation without suffering significant financial penalty. The managers of TILLERMAN must therefore be seen as offering the services of their vessel under normal commercial conditions.

17.11   It is not clear whether the action taken by the MPCU, in underwriting possible losses, will have set a precedent which will be of assistance during any future salvage operations of this type in UK waters. However, such action does not avoid the need to have the full co-operation of the manager of the lightening vessel without which no suitable lightening tanker could ever be made available. The pre-agreement of tanker managers may be of value in saving valuable time in future incidents, possibly in the form of 'stand-by contracts' with MPCU. There would also appear to be some merit in extending the powers of the Secretary of State to allow him to intervene in the chartering process of vessels under circumstances where an owner is constrained from offering the use of his vessel.

17.12   Due to the above mentioned difficulties in obtaining conventional tankers for lightening purposes, there may well be value in giving consideration to other methods which may be available to receive oil in order to lighten a casualty. One system is a flexible oil tight envelope which floats alongside the casualty. At their present state of known development such methods are restricted to receiving oil in maximum parcels of 1,000m3. However there may well be other systems available or in the process of being developed. Recognising that the stated intended use of the stored MPCU salvage equipment is that of ship-to-ship transfer, a receiving vessel other than a commercial tanker, may well enhance the value and flexibility of the existing equipment.

17.13   It is accepted that a system of this type, even in an enhanced yet to be developed state, may never be suitable for removing all cargo from a large damaged tanker. However, in an incident where cargo or bunker tanks of a vessel are breached, removing even some oil from these tanks alone would have the benefit of reducing the total quantity which could be released to the environment. A secondary benefit would be to increase the size of the water plug in these tanks, further reducing the chances of pollution if the vessel was aground or later ran aground. Accepting that the primary role of MPCU is that of preventing pollution, consideration of the merits and uses of these systems should be undertaken by that organisation with a view to future deployment. It is considered that such a system may have the potential to enhance the pollution prevention capability of MPCU.

18. AVAILABILITY OF VESSEL'S MACHINERY

Steering gear

18.1   During various stages of the salvage operation the steering gear was used and found to be satisfactory. After completion of the salvage operation, while the vessel was berthed alongside Herbrandston Jetty, steering gear tests were performed which were also satisfactory. When the vessel was in dry dock an inspection of the rudder revealed no damage, therefore it is concluded that the steering gear was operational and undamaged throughout the incident.

Fuel Supply Systems

18.2   The main engine, boilers and main generators of SEA EMPRESS are all designed to operate primarily on heavy fuel oil. The normal operational practice on the vessel was to employ heavy fuel oil for all of these items during all seagoing, manoeuvring and cargo operations. This 'single fuel concept' is an arrangement which is now common on many modern vessels. Only when a period of idleness can be anticipated, such as a refit or dry docking, is diesel oil substituted for heavy fuel oil. Diesel oil does not require pre-heating for use therefore facilitates the reactivation of the vessel's machinery from the cold state. It is also the practice to maintain diesel oil within the fuel system of one of the main generators which is idle and this becomes the stand-by generator. When required, diesel oil is supplied to the main engine and generators from the diesel oil service tank having a capacity of 7.8m3. This compares to the heavy fuel service tank capacity of 39m3.

18.3   On those rare occasions when heavy fuel needs to be replaced by diesel fuel in any engine this is undertaken with the engine in operation. As fuel is consumed by the engine, diesel fuel is introduced into the fuel system, so gradually replacing the heavy fuel. To perform this change over without an engine running, and with the fuel system cold, cannot be seen as a routine operation. It would be a rather difficult operation due to the problems of attempting to pump cold and very viscous heavy fuel oil. The time required to perform an operation of this type would be difficult to predict and it is unlikely that it would ever have been performed during the previous life of the vessel.

18.4   During the vessel's approach to Milford Haven, heavy fuel oil was in use by all of the vessel's main items of machinery mentioned above. This remained the situation until the crew were evacuated from the vessel, with the salvors and others, in the early hours of Sunday 18 February.

Compressed Air Supply

18.5   For several extended periods throughout the salvage operation the main engine of the vessel was in manoeuvring mode and was operated as such to the pilots' and salvors' requirements. The earliest occurrence of a potential problem with any of the main machinery systems concerned the supply of compressed air employed for main engine starting purposes.

18.6   Early efforts to ventilate the pump room required the use of two portable ventilation fans which were powered by compressed air. The compressed air was from the vessel's own supply. Continual running of these two fans, coupled with the starting air requirements of the main engine during the manoeuvring operations of Friday placed a demand on the vessel's air compressors which caused concern. To a limited extent, and for a very brief period, this concern was compounded by a minor difficulty with one of the vessel's air compressors which required it to be shut down for a short period. One air driven ventilation fan was shut down in order to reduce the demand for compressed air. Once this was done there were no further concerns on the matter of compressed air supply and demand until much later in the salvage operation on Wednesday 21 February.

Main Engine

18.7   No work was performed on the main engine between the evacuation in the morning of Sunday 18 February and reboarding on Monday morning. Only the vessel's emergency generator was in operation during this period, all other machinery was idle and allowed to cool.

18.8   On reboarding the vessel on Monday, the declared priority was to restore main electrical power and no particular emphasis was placed on rapidly restoring the main engine to operating mode. The absence of steam for fuel oil heating purposes had allowed the heavy fuel oil contained within the fuel system of the main engine to cool. Efforts to replace this heavy fuel with diesel were commenced once main generators and boilers were restored to service. This operation was underway when a request was made for information on the status of the main engine at 1713 hrs. In the circumstances it was not available for use.

18.9   The operation to substitute diesel oil for heavy oil in the main engine's fuel system commenced on Monday was only partly completed by the time the vessel was again evacuated at about 2240 hrs on that day. However, shortly after the vessel's engineers reboarded on the Tuesday morning they commenced warming through the main engine cooling system and recommenced the process of substituting diesel oil for heavy oil in the main engine's fuel system. These operations had been completed, and the main engine tested on diesel fuel, by the early afternoon. During the attempts to refloat the vessel between 1700 hrs and 1945 hrs later that day the main engine was operated with diesel oil on many occasions, and at various speeds between Full Ahead and Full Astern, with no difficulty being experienced until shortly before these efforts were abandoned at 1945 hrs. While the main engine was running it slowed intermittently when a spurious overspeed signal was received by the engine's control system. However, the main engine continued to start and run until the end of this refloating attempt, albeit in a fashion not consistent with control lever settings. When all persons again evacuated the vessel that evening the main engine's fuel system contained diesel oil.

18.10    Salvors and members of the vessel's crew boarded the vessel again during the morning of Wednesday 21 February. Preparations were made to restore services and to identify the cause of the main engine overspeed trip. The problem was identified as being due to a failed contact possibly aggravated by the vibration levels generated during the refloating efforts of the previous day. The problem could only be overcome successfully by controlling the engine from the emergency engine control station. Operating in this emergency mode the main engine was started at 1814 hrs.

Main Generators

18.11   Immediately prior to the evacuation early on Sunday morning all machinery, including the boilers, was shut down with the exception of one generator. This was running on heavy fuel oil and it was anticipated that it would stop at some unknown time after the evacuation, due to the heavy fuel oil cooling in the generator's fuel system. However it was known that once this had occurred the emergency generator, which operates on diesel oil, would automatically cut in. This is a feature of the system and slightly less than two hours later this happened. Many observers of these events interpreted this development as an indication that the vessel's engine room had been breached and flooded. This was not the case.

18.12   The vessel was next boarded by a small group of salvors on the Sunday. Although some of the vessel's engineers made an attempt to board the vessel, this was aborted due to concern for their safety. This group of salvors made unsuccessful attempts to restore the main power supply by starting a main generator but these efforts failed in spite of technical information being passed to them via VHF from the vessel's Chief Engineer and her Technical Manager. The emergency generator continued to run. This episode, however insignificant it may have been to the overall operation, does highlight the potential difficulties which may be encountered by salvors and even the most experienced engineers in activating a vessel's machinery, when it is equipped with sophisticated control and monitoring systems, without direct assistance from persons familiar with the equipment.

18.13   When the vessel's engineers reboarded the vessel on the Monday morning they were able to start No 2 main diesel alternator, it being selected because its fuel system contained diesel oil, and the emergency generator shut down. Although this generator was left running on diesel oil when the vessel was evacuated late on Monday night, it shut down due to the contents of the diesel oil service tank being exhausted. Again the emergency generator started automatically and when the vessel was reboarded on Tuesday morning the diesel oil service tank was quickly replenished by crew members allowing the main generators to be re-started. Main electrical power continued to be available from that time until completion of the salvage operation.

Inert Gas System

18.14   For efficient and effective operation of the inert gas plant the boilers have to be on load. On this vessel a dump line is available which connects the steam outlet line from the main boilers to the main condenser. This line allows the steam produced by the boilers to be passed to the main condenser, so placing a load on the boilers and allowing inert gas to be produced in acceptable quantities.

18.15   Two problems were experienced with the inert gas system. Firstly, there was a high water level in the scrubber tower which caused the system to shut down. At the time the vessel had a significant list. However, when the magnitude of this list was reduced the scrubber tower commenced functioning correctly. Although a blocked vent pipe of the water overflow line from the scrubber tower had been found, and rectified, it is not clear whether the vessel's list or this blocked pipe was the true cause of the difficulty.

18.16   The second problem occurred when the water seal of the inert gas main pressure/vacuum breaker was lost at some stage before the Wednesday morning. As the vessel's fire main, which would have been used to refill it, was being employed to transport compressed air forward to the damaged ballast tanks it was necessary to refill the water seal using buckets.

Ballast System

18.17   Soon after the initial grounding the list was reduced by running sea water into the two port side ballast tanks, Nos 2 and 4, under gravity via the ballast main from the damaged starboard side tanks which had flooded. The success of this operation indicated that the remotely operated ballast valves, on the ballast main within the centre tanks, were functioning and that the ballast main was largely intact. Later, doubts as to the integrity of the ballast main were expressed during the operations of Saturday 17 February when efforts were being made to fill No 2 Port Ballast and the Fore Peak tanks. A test of the ballast main was performed which indicated that it was intact.

18.18   Due to flooding in the pump room the locally operated valves for the ballast system were immersed thus making it essential to pump out the pump room before the ballast system could be deployed in its standard mode of operation. Evidence from initial efforts to pump out the pump room using MPCU portable pumps, would suggest that the bottom damage from the initial grounding was limited. However, a later inspection of the ballast main when the vessel was in dry dock, showed that it had suffered serious damage within the pump room. The damage, in the form of fractures adjacent to two valves, was consistent with the area of bottom damage at the port side of the pump room. Such damage would have presented some problems with any ballasting operations being carried out via the pump room side of the system, particularly due to leakage into the pump room. However, partial ballasting of any intact tank from any damaged tank would have been possible at almost any stage of the incident, without requiring access to the pump room.

18.19   Other damage to the ballast main, which passes fore and aft through the lower part of the centre cargo tanks, was also found while the vessel was in dry dock and was consistent with the bottom of the vessel being set up in way of the cargo tanks. However this setting up of the line was accommodated by the bellows piece and did not lead to fracture of the system.

18.20   The Aft Peak tank was employed for ballasting purposes during the salvage operation. This tank is not served by the ballast main or the main ballast pumps. It is filled or emptied using pumps within the engine room and the system was available throughout the incident.

Integrity of Machinery Spaces

18.21   A rupture of the Port Double Bottom Diesel Oil Tank occurred on the morning of Wednesday 21 February, the very last day of the salvage operation. When the vessel was in dry dock the rupture was found to be a small puncture rather than a massive structural failure. The size of the puncture was minimal, consistent with being pierced by a sharp object, and resulted in water entering the tank. No significant pollution is likely to have been caused as this damage was in the lowest part of the tank.

18.22   On three occasions the starboard ballast pump gland allowed a water/oil mixture to pass from the pump room into the engine room. Although on one occasion a gas test was performed to establish whether explosive vapours were entering the engine room, and this proved negative, this leakage was slight and caused no great concern.

Deck Machinery

18.23   The deck machinery is hydraulically operated and whenever a main generator was running it was possible to supply hydraulic power to any item of the vessel's deck machinery. Although minor problems did occur, largely due to lack of familiarity with the hydraulic systems on the part of salvors' staff, no failure of any of these systems was reported.

18.24   During the manoeuvring operations of Saturday afternoon a minor failure, in the form of a sheared pin in the handwheel of the extended spindle to the brake of the starboard windlass, caused some difficulty. This was promptly repaired and it caused no further problem.

Conclusions

18.25   No major or catastrophic failure of any of the vessel's machinery or equipment occurred which can reasonably be considered to have influenced the outcome of this incident. However, several incidents illustrate the problems which may be encountered by salvors when they board a casualty, the layout and machinery of which is unfamiliar to them. The ever increasing sophistication of marine machinery, and in particular that of control and monitoring systems, highlights the importance of a casualty's crew being able to continue to offer their assistance throughout a salvage operation.

19. LOSS OF OIL FROM VESSEL

General

19.1   Prior to the accident SEA EMPRESS was carrying a cargo of some 130,000 tonnes of crude oil (this figure is based on the vessel's calculations). She also had in her engine room tanks some 2,300 tonnes of heavy fuel oil, 86 tonnes of diesel oil and 60 tonnes of lubricating oil. The heavy fuel oil was contained in wing tanks well above the bottom of the ship while most of the diesel oil was stored inside the engine room double bottom tanks.

19.2    In total 71,800 tonnes of crude oil was lost from the vessel during the initial grounding and the subsequent salvage operation. The Inquiry has endeavoured to determine how those losses occurred. The purpose of this aspect of the Inquiry is not only to provide data on how the oil was lost from the casualty but also whether at any point in the salvage operation a part of the cargo was deliberately discharged into the sea to save the vessel.

19.3   As the operation to salve the vessel ran into difficulties and more cargo tanks were ruptured more oil was lost from the vessel. Oil is lost to the sea from a damaged cargo tank in a number of ways:

- when the vessel has forward motion or is stationary in a fast flowing current the oil in contact with the passing water at any opening will tend to be drawn out;

- as the vessel rises and falls in a swell further oil will be lost through the hull damage or even forced out of unsecured deck openings due to the movement of the vessel in a seaway;

- because the oil level within a damaged tank will find its own level in hydrostatic balance with the external sea surface.

19.5   Hydrostatic losses occur in two ways. Firstly, when the vessel is afloat and the oil in ruptured tanks generates a greater pressure, due to the level of oil in the tanks, than does the seawater at the position of the damage there will be an outflow of oil. This outflow will continue until the falling oil level decreases to a point where oil pressure and seawater pressure are equal. Secondly, with the vessel aground on a falling tide, as the sea level drops the external pressure from the sea which is keeping the oil inside the vessel reduces. Once the sea level reduces below a critical height oil will flow out from the ruptured tanks.

19.6   There are several difficulties in analysing the oil losses over any specific period of the SEA EMPRESS salvage. These difficulties are associated with the accuracy and sparsity of data available. Also, not having a record of the precise time of many events is a particular problem. At the entrance to Milford Haven, the tides rose and fell at a maximum rate of about one metre every 35 minutes. A difference of only one metre on vessel draught, or an error of 35 minutes on event times, could lead to an inaccurate estimate of oil loss by up to 7,000 tonnes, which is significant. Another difficulty is the determination of the vessel's precise location and heading at any time. The problem is further compounded because of the impossibility of knowing precisely which part of the vessel grounded first on each occasion, and hence the corresponding water depths when the vessel first grounded.

19.7   In order to minimise the inevitable errors in the data, particular care has been taken to obtain consistency between the various records and wherever possible to handle key parameters on a relative rather than an absolute basis. The approach generally adopted was to deduce a consistent series of events which fits the available data and which, if possible, would have resulted in an oil loss at least equal in quantity to that which can be deduced from records. It needs to be borne in mind that the measurement of oil in circumstances such as those surrounding the salvage is not precise and for the purposes of this aspect of the Inquiry quantities quoted have been calculated and estimated to the nearest thousand tonnes.

Measured Oil Losses

19.8   Measurements were taken by the salvors on four occasions which allowed them to determine the quantity of oil remaining on board. The first measurements were taken in the afternoon of Monday 19 February which showed that 111,000 tonnes of cargo remained on board, therefore 19,000 tonnes had been lost. The second measurements were taken in the morning of Tuesday 20 February and these showed that 95,000 tonnes remained on board. This meant that a further 16,000 tonnes had been lost, taking the total lost to 35,000 tonnes. The third set of measurements were taken in the morning of Wednesday 21 February. These showed that 63,000 tonnes now remained on board therefore a further 32,000 tonnes had been lost bringing the total to 67,000 tonnes. The fourth and final measurements were taken in the morning of Thursday 22 February when the vessel was alongside at Herbrandston Jetty. These showed that 56,000 tonnes remained on board which meant that a further 7,000 tonnes been lost bringing the total lost to 74,000 tonnes.

Once the remaining cargo had been discharged, which it was possible to measure accurately, it was calculated that 58,200 tonnes had been off-loaded therefore a total of 71,800 tonnes had been lost. The difference between the actual quantity lost and the estimated quantity, some 2,200 tonnes, reflects the problems with measuring techniques during a prolonged and difficult salvage operation.

Causes of Oil Losses

19.9   It is not clear what oil was lost as a direct consequence of the initial grounding. The vessel reported a loss of some 6,000 tonnes, but it is believed that this figure was based on erroneous data. Calculations based on the condition of the vessel after flooding indicated that the oil loss at this time would have been likely to be about 2,500 tonnes. It is clear however, that the vessel lost no further oil during Friday 16 February or during Saturday 17 February until she grounded again that evening.

19.10   With the first measurement of oil on Monday 19 February it was determined that some 19,000 tonnes of oil had been lost. This total oil loss was an aggregate of the oil lost in the initial grounding and the oil lost due to the groundings on Saturday 17 February and Sunday 18 February. It is not possible to quantify the oil losses in these individual events but as the vessel was effectively out of control and unmanned for long periods the losses were clearly not influenced, either adversely or beneficially, by the salvage team.

19.11   For the remainder of the salvage operation the periods between each set of measurements referred to above were examined to identify the causes for the estimated quantities of oil lost. Examination included consideration of the various salvage activities which had been undertaken, estimates of when further breaches of the hull occurred, the locations of the various groundings, the rise and fall of the tide, the draught of the vessel and witness evidence. Allowing for the problems referred to in paragraphs 19.6 and 19.7 above it has been possible to determine with a reasonable degree of confidence how the losses occurred.

19.12   Of the losses which occurred between the time of the first measurements on Monday 19 February and those on Tuesday 20 February, that is 16,000 tonnes, it is concluded that the loss was wholly due to stranding of the vessel. It was not exacerbated by the actions on board of the salvors who manned the vessel infrequently over this period.

19.13   During the next period, between the measurements taken on Tuesday 20 February and Wednesday 21 February, the loss was 32,000 tonnes. Some 16,000 tonnes of this loss occurred naturally over the low water period in the early afternoon of Tuesday. This was not exacerbated by the salvors preparations to refloat the casualty. However, no wholly satisfactory theory has been identified for the precise circumstances surrounding the remaining 16,000 tonnes of the total which was lost during this period. It is known that a draught reduction of about 3 metres was achieved at the time of the failed refloating operation. It is also known that the casualty drifted to the west into shallower water during the refloating attempt. Calculations have shown that if the vessel stranded at this reduced draught then an oil loss of the order of 16,000 tonnes would result. It therefore seems reasonable to conclude that a further 16,000 tonnes of oil was lost over the low water period early on Wednesday morning because of the significant reduction in the low water draught of the casualty which resulted from the failed refloating attempt.

19.14   The final period analysed, between the measurements taken on Wednesday 21 February and Thursday 22 February, included the pressurisation of various tanks and the other activities by the salvors which resulted in the successful re-floating operation. The 7,000 tonnes of oil lost to the sea in this period was very probably a direct consequence of the actions required of the salvors to ensure that the re-floating operation was successful. It was not a premeditated act, rather a risk to be taken to avert a much greater potential oil loss. The alternative involved a much greater risk of further oil pollution.

19.15   The Inquiry could not find any evidence to show that at any stage during the salvage operation did the salvors deliberately discharge oil into the sea.