Report of Investigation into the fatal accident on a mooring gang crew at government mooring buoy A43 on 6 April 2007
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Purpose of Investigation This incident is investigated, and published in accordance with the IMO Code for the Investigation of Marine Casualties and Incidents promulgated under IMO Assembly Resolution A.849(20). The purpose of this investigation conducted by the Marine Accident Investigation and Shipping Security Policy Branch (MAISSPB) of Marine Department is to determine the circumstances and the causes of the incident with the aim of improving the safety of life at sea and avoiding similar incident in future. The conclusions drawn in this report aim to identify the different factors contributing to the incident. They are not intended to apportion blame or liability towards any particular organization or individual except so far as necessary to achieve the said purpose. The MAISSPB has no involvement in any prosecution or disciplinary action that may be taken by the Marine Department resulting from this incident. 3
Table of Contents Page 1 Summary 2 2 Description of the Vessels and the Mooring Buoy 3 3 Sources of Evidence 9 4 Outline of Events 10 5 Analysis of Evidence 12 6 Conclusions 22 7 Recommendations 23 8 Submissions 24 9 Appendix 25 1
1. Summary 1.1 An accident happened at the government mooring buoy A43 on 6 April 2007. While a mooring gang of three were standing on the mooring buoy to secure the anchor chain of m.v. Metropolis to the buoy, the mooring buoy was suddenly tilted and the mooring eye fitting was lifted up from its cylindrical trunking. Two of the mooring gang crew fell into the water while the other fell and was trapped in the cylindrical trunking of the mooring buoy. The latter was crushed to death by the mooring eye fitting. 1.2 The investigation revealed that the Vessel was in motion and moved away from the mooring buoy after the mooring gang crew had secured the ship s anchor chain to the buoy. As a result, the mooring buoy was tilted and the mooring eye fitting was pulled out from the cylindrical trunking of the buoy. 1.3 The investigation has also identified the following contributory factors to the accident: The buoy mooring operation poses significant inherent risks to the mooring gang crew. They are required to remain on the mooring buoy for a prolonged period; Excessive discrepancy on the settings of propeller pitch angles existed between the local position and the bridge control console. The propellers produced thrust even the pitch control was put to zero ; and Poor communication among the working teams during the mooring operation.. 2
2. Description of the Vessels and the Mooring Buoy 2.1 M.V. "Metropolis " a) Particulars of the Vessel Name of the Vessel : " Metropolis " Port of Registry : Panama IMO No. : 7215161 Official No. : 28045-01A Call Sign : H9AJ Classification Society : Germanischer Lloyds Type of Ship : Passenger / Ro-Ro ship Year of Built : 1972 Built At : Kawasashi Heavy Industries Co. Ltd., Japan Ship Manager : Wallem Ship Management Ltd. Length : 148.78 metres Breadth : 22.89 metres Depth : 8.01 metres Gross Tonnage : 17,261 Deadweight : 3,472 Net Tonnage : 10451 Engine Power : 14,712 kw Fig. 1: The outlook of the passenger ship Metropolis 3
b) "Metropolis" (hereinafter referred as the Vessel) is a steel passenger ship built by Kawasashi Heavy Industries Co. Ltd., Japan in 1972. She is powered by two MAN-KAWASAKI V9V 40/54 diesel engines geared to two controllable pitch propellers, capable of developing a total power of 14,712 kw with a service speed 18.75 knots. The Vessel was owned by Metropolis Cruise Co., Ltd. and managed by Wallem Shipmanagment Ltd. c) Engine movements of the Vessel can be controlled from the bridge by a duty officer. The Vessel is equipped with one bow thruster of 600 kw to provide side power to improve maneuverability at slow speed. d) The Vessel provides cruise to nowhere daily regular passenger services from its base in Hong Kong. e) The Vessel was normally assigned to moor at the mooring buoy A43 with the starboard anchor chain when in Hong Kong. 4
2.2 Pilot boat Harbour 32 a) Particulars of the Vessel Name of the Vessel : Harbour 32" Licence No. : B4523 Type of Ship : Transportation boat (Pilot launch) Year of Built : 1986 Built At : Cheoy Lee Shipyards Limited, Hong Kong Ship Owner : Joy Harbour Investment Ltd. Length : 12.98 metres Breadth : 4.23 metres Depth : 1.69 metres Gross Tonnage : 34.65 Net Tonnage : 20.64 Engine Power : 223.8 kw Fig. 2: The pilot boat Harbour 32 b) "Harbour 32" (hereafter referred as the Pilot Boat) is a fibre glass reinforced traffic launch built by Choey Lee Shipyard, Hong Kong in 1986. She is powered by a Cummins diesel engine and capable of developing total power of 223.8 kw. The Pilot Boat is owned by Joy Harbour Investment Ltd. which is a subsidiary company Limited of Weal Ocean Limited. The Weal Ocean Limited is a principal contractor of the Hong Kong Pilot Association Limited 5
to provide pilot boats and mooring gang crew for pilotage and mooring services. c) A Coxswain, an Engineer and two sailors (Sailor A and Sailor B) were working as a team on board the Pilot Boat. During the buoy mooring operation, the Coxswain was at the helm of the Pilot Boat while the Engineer, the Sailor A and Sailor B were members of the mooring gang. 6
2.3 The mooring buoy a) Particulars of the mooring buoy Buoy number : A43 Class : A Identification number : HO308 Year of Manufacture : 2002 Built at : Guangxi Guijiang Shipyard, Wu Zhou, Guangxi, China Owner : Marine Department Outside diameter : 3.66 metres Depth : 1.845 metres Weight : 6 metric tones (approximate) Weight of sinker : 90 metric tons Position of Sinker : 22 17.93 N 114 13.00 E Length of chain : 40 metres (approximate) Fig. 3: The mooring buoy A43 7
b) Mooring buoy is a floating device used to keep one end of the mooring cable on the water surface. There are 21 A Class and 10 B Class mooring buoys mostly laid within the port of Hong Kong for ship mooring. The mooring buoy A43 (hereafter referred as the mooring buoy) is one of the A Class mooring buoys for vessels not exceeding 183 metres in length. c) The mooring buoy is a steel cylindrical structure of 3.66 metres in diameter and 1.845 metres in height. The watertight structure provides buoyancy for supporting the weight of the chain cable and the mooring eye fitting about 6.7 metric tones. At the centerline of the mooring buoy, there was a taper shaped cylindrical trunking for passing the chain cable and providing a self-aligned seat for the cable support (see fig.4). On top of the cable support, there was an eye shackle forming a mooring eye fitting for mooring to the anchor chain of a ship. Eye Shackle Cable Support Mooring eye fitting 42.52 m 0.58 m Diameter 1.69m Diameter 3.66m The sinker Fig. 4: Drawing of the mooring buoy d) The lower end to chain cable is connected to a 90 metric tonnes sinker which sit on the seabed in the position of 22 17.93 N 114 13.00 E. 8
3. Sources of Evidence a) The Master and Crewmembers of passenger ship Metropolis b) The Coxswain and Crewmembers of pilot launch Harbour 32 c) The Hong Kong Pilot Association Limited d) The Weal Ocean Limited e) The Pilot on board Metropolis f) Vessel Traffic Centre, Marine Department g) Pilotage Unit, Marine Department h) Aids to Navigation and Mooring Unit, Marine Department 9
4. Outline of Events 4.1 In the morning of 6 April 2007, m.v. Metropolis (hereafter referred as the Vessel) returned to Hong Kong waters after a cruise to nowhere trip. At 0837, the Vessel arrived Tathong Channel pilot station (22 16.00 N 114 15.70 E) where a pilot boat Harbour 32 (hereafter referred as the Pilot Boat) had been standing by. A pilot came onboard the Vessel from the Pilot Boat there. 4.2 The Pilot Boat and the Vessel proceeded to the mooring buoy A43 which the Vessel was going to be moored. At about 0850, the Pilot Boat arrived at the mooring buoy, the mooring gang crew (Sailor A and Sailor B) put a wire sling on the eye shackle of the mooring buoy. The mooring gang crew returned to the Pilot Boat, then she sailed towards the Vessel. 4.3 At 0855, the main engines and the bow thruster of the Vessel stopped. She was about 150 metres east of the mooring buoy with a drifting speed of about 1 knot towards the mooring buoy. The mooring gang crew (Sailor A and Sailor B) picked up one end of the Vessel s headline rope from the Pilot Boat to the buoy. The mooring gang crew immediately returned to the Pilot Boat after securing the headline rope to the wire sling at the mooring buoy. 4.4 The crewmembers at the foredeck of the Vessel retrieved the headline in order to pull the Vessel close to the mooring buoy. At 0900, the Vessel was brought to the position of the mooring buoy. The mooring crew consisted of the Engineer, the Sailor A and the Sailor B boarded the mooring buoy to secure the anchor chain to the mooring buoy. After securing the anchor chain, the mooring eye fitting was suddenly pulled up by the anchor chain caused the mooring buoy to tilt at a large angle. 4.5 The Engineer and the Sailor B fell into the sea while the Sailor A fell and trapped inside taper shape cylindrical trunking when sinker chain cable returned back to the cylindrical trunking. The cable support crushed the head of the Sailor A (see figure 5). The Engineer and Sailor B were not injured and swam back to the Pilot Boat. 4.6 The Sailor A suffered serious injury and remained inside the lower portion of the cylindrical trunking of the mooring buoy. The Coxswain and the Pilot reported the incident to the Pilot Association and Vessel Traffic Centre of Marine Department respectively. Soon rescue team arrived and the Sailor A was taken out from the mooring buoy chain trunking. He was conveyed to North Point Pier and was certified dead by an Ambulance Officer. 10
The movement of the Vessel. Movements of the anchor chain and mooring eye fitting (moving upward) Movements of the anchor chain and mooring eye fittings (moving forward) Fig. 5: Sketches showing the sequences of the accident 11
5. Analysis of Evidence Manning of the Vessel 5.1 The Vessel had a crew of 224 Chinese and 1 Malaysia nationals. The deck department consisted of 1 Master, 1 Chief Officer, 3 Second Officer, 1 Bosun, 1 Carpenter, 3 Able Seamen, 3 Ordinary Seamen. The engine department consisted of 1 Chief Engineer, 1 Second Engineer, 1 Third Engineer, 1 Fourth Engineer, 2 Electricians 3 Motormen, 4 Wipers and 3 Fitters. The remaining crewmembers were belonged to catering department. 5.2 During the buoy mooring operation, the Vessel mainly consisted of three working parties. The bridge team, the foredeck team and the engine room team. The bridge team was manned by the Master, two Second Officers, an Able Seaman and the Pilot for maneuvering the Vessel. The foredeck team was manned by the Chief Officer, the Bosun, the Carpenter, two Able Seamen and three Ordinary Seamen controlling the mooring ropes and anchor chain. The engine room was manned by the Chief Engineer, the Third Engineer and an Oiler. The manning scale of the Vessel for the buoy mooring operation is found to be adequate. The Master 5.3 The Master held a Chinese Certificate of Competency as Master. He had 14 years of seagoing experience and had been sailing as master for 7 years. He had been working on board the Vessel since February 2007. The Pilot 5.4 The Pilot held a Canadian Certificate of Competency as Master and a class I Hong Kong Harbour Pilot License. He had more than ten years seagoing experience and he joined the Hong Kong Pilot Association Ltd. (the Association) as a harbour pilot in 1989. The Coxswain 5.5 The Coxswain of the Pilot Boat had been serving for the Weal Ocean Limited since 1972. He was promoted to a Coxswain in 1980. Apart from taking charge of the Pilot Boat, he was also responsible for monitoring the situation and providing support while the mooring gang working on the mooring buoy. 12
The Sailor A (the deceased) 5.6 The Sailor A had been serving for the Weal Ocean Limited since 1979. Prior joining the Weal Ocean Limited, he was a fisherman working for local fishing vessels. According to the Coxswain and the crewmembers of the Pilot Boat, Sailor A was experienced in mooring operation. Working fatigue 5.7 The working period of the mooring gang crew was on 24-hour basis. After taking a day of rest, the Coxswain and the mooring gang crew started their work in the morning of 6 April, i.e. few hours prior to the accident. It appears that fatigue is not a contributory factor to the accident. Control of the Vessel during the mooring operation 5.8 During the buoy mooring operation, the Master ordered engine movements and one of the Second Officers was at engine control to maneuver the Vessel. The Pilot gave advice to the Master whenever necessary. Both the Master and the Pilot commented that the buoy mooring operation was in good working order before the happening of the accident. The environmental conditions 5.9 The accident happened in the morning with good daylight. The weather was cloudy and clear with good visibility. Northerly wind about 1 knot was prevailing in the area. Tidal stream current was running westerly at about 0.7 knot. The effects of the wind and the tidal current would cause the Vessel to drift in a westerly direction. At time of the accident, the heading of the Vessel was abeam to the direction of the tidal stream. The current pushed the Vessel to the west sideway at its maximum rate from the starboard side. As the anchor chain of the Vessel had been secured to the mooring buoy, the movement of the Vessel was restricted by the sinker of the mooring buoy and its chain cable. At this juncture, the Vessel was swung into the direction of the current as shown in figure 6. As a result, high dragging force was put on the chain cable. 13
The Vessel (final position) The mooring buoy Movement of the Vessel The Vessel (initial position) The sinker (on the seabed) Tidal current Fig. 6: Effects of tidal current to the Vessel Buoy mooring procedures 5.10 According to the Buoy mooring diagram provided by the Association that the ship s crew and the mooring gang crew should follow the procedures on the Preparation for Buoy Mooring and the Final Mooring Arrangement after Secured to Buoy (see figure 7). 5.11 Ship s crew is required to make preparation work according to the procedures on the Preparation for Buoy Mooring. On completion of the buoy mooring operation, chain rope, and headline are to be rigged as in the drawing as in the Final Mooring Arrangement after Secured to Buoy. During the mooring operation, the mooring gang crew are responsible to carry out the following work procedures: To secure the headline onto the eye shackle of the mooring buoy with a wire sling when the ship is about 100 metres from the mooring buoy; To secure the chain rope (anchor chain) onto the eye shackle of the mooring buoy when the bow of the ship is above at the position of the mooring buoy; To disengage the headline, pass it through the eye shackle and tie it with the messenger rope from the Vessel. The headline is then retrieved to the ship and serves as a slip rope and secured to the ship. The slip rope can be used to heave the ship to the buoy for disconnecting the mooring chain on departure. 14
Fig. 7: Buoy mooring diagram 5.12 The Weal Ocean Limited, the principal contractor of the Association provides a Guidelines for Mooring for the mooring gang crew (see appendix 1). The purpose of the guidelines is only to lay down steps for the mooring gang crew to complete their task but not appropriately address the safety precautions for the mooring gang crew. It also appeared that the mooring gang crew was not aware of the existence of the guidelines. They relied on their experience. 15
The time sequence of work before the accident 5.13 The mooring gang crew had boarded the mooring buoy three times for the mooring operation. The time sequence of the work before the accident was as follows: Time Work done Location of the mooring The Vessel s gang crew velocity (Approximate) 0850 Placed a wire sling onto the The Sailor A and the Sailor 5 knots at mooring buoy. B on the mooring buoy. course 296 o Returned to the Pilot Boat immediately on completion of the work. 0855 Took the headline rope The Sailor A, the Sailor B 1 knot at from the Vessel s foredeck and the Engineer on board course 296 o crew. the Pilot Boat. 0857 Secured the headline rope The Sailor A and the Sailor 1 knot at with the wire sling onto the B on the mooring buoy. course 318 o eye shackle of the mooring Returned to the Pilot Boat buoy. immediately on completion of the work. 0900 Engaged the Vessel s anchor The Engineer, Sailor A and 1 knot at chain to the eye shackle of the Sailor B on the course 336 o the mooring buoy; mooring buoy. Disengaged the headline rope from the eye shackle; Took a messenger rope from the Vessel and tied it up to the headline rope. The accident happened at about 0902 when the mooring gang crew were tying 16
up the messenger and the mooring rope, anchor chain lifting up the mooring eye fitting and tilting the mooring buoy. Movement of the Vessel while working on the mooring buoy 5.14 Based on the radar track record from Vessel Traffic Centre, the movements of the Vessel were recorded as follows: 22 o 18.1 N Passenger ship Asia Star Position of buoy sinker A17 The Vessel Position of buoy sinker A43 22 o 17.9 N 0903 0902 0901 0900 0859 114 o 12.7 E 114 o 12.9 E 114 o 13.1 E Time Heading Turning angle The angular movement of the Vessel (deg/sec) 0 100m 200m 300m 400m 0859 0900 0901 0902 0903 325 336 361 371 386 11 0.183 25 0.417 10 0.167 15 0.250 0.254 (Average) Fig. 8: Movements of the Vessel during the mooring operation The rate of turn of the Vessel was estimated to be about 0.254 per second (table in figure refers). The speed of the Vessel was about 1 knot when she arrived at the mooring buoy s position. The mooring gang crew boarded the mooring buoy 17
for the mooring work operation while the Vessel was in the position close to the maximum outreach of the mooring buoy. 5.15 The maximum horizontal outreach of the mooring eye fitting from the sinker was about 40.91 metres (see fig 9). According to the plotting of the radar track record. The Vessel had reached the maximum horizontal outreach at the time of the accident around 0902. As the Vessel continued to move, the mooring buoy chain cable was dragged and the mooring eye fitting could be drawn out from the mooring buoy. The Vessel (Looking aft) Mooring eye fitting The sinker 42.52 m Maximum horizontal outreach 40.91 m 11.59 m Fig. 9: Sketch of the maximum outreach of the mooring eye fitting 5.16 Shortly prior to the accident, both the Pilot and the Coxswain found that the Vessel was moving significantly. After the Pilot confirmed with the Coxswain of the Pilot Boat that astern engine power was needed, he immediately advised the Master of the Vessel for astern power. However, the accident happened before the action could be taken by the Master. 18
Communication 5.17 During the mooring operation, the view from the bridge to the mooring gang crew was obstructed by the superstructure of the Vessel (see figure 10). Figure 10: The view from the bridge to the mooring buoy V.H.F. sets were provided for communication between various parties. The Coxswain and the Chief Officer should report the progress of the mooring, the Vessel s movement, etc to the Pilot and the Master respectively. However, the communication between the various parties was found inadequate, most of the information had not been reported to the bridge team prior to the accident. According to the records of the V.H.F. conversation from Vessel Traffic Centre, it appeared that there were no communications between them prior to the accident. The first communication between the Pilot and the Coxswain was only transpired when the Pilot observed the speed of the Vessel was abnormally fast. Controllable pitch propellers 5.18 During the mooring operation, the propellers pitch angle at the bridge control console was put to zero pitch positions. If errors existed between the bridge control and local position, the propellers were not in neutral position and the Vessel was still in motion. The discrepancy in settings at the control of the controllable pitch propellers were verified with the following results: 19
Port Propeller Pitch Starboard Propeller Pitch Reading at bridge control 0 º 0 º Reading at local position 1 º (Forward) 0.25 º (Astern) Discrepancy on the pitch angles was found between the bridge control and the local control position. As such even the bridge control was put at zero position, resultant forward movement and starboard turning moment from the propellers might still act on the Vessel during the mooring operation. Relative movements between the Vessel and the mooring buoy 5.19 The combined effects on the discrepancy in settings of the pitch of the propellers, the Vessel s momentum and tidal stream caused the Vessel to move during the mooring operation. The Vessel was moving and turning steadily while it was reaching the mooring buoy. If the speed and turn rate of the Vessel could be lowered during the mooring operation, the risk of lifting up the mooring eye fitting and tilting the mooring buoy would be reduced. For the sake of safety, the mooring gang crew should not board the mooring buoy when there is still an excessive relative movement between the Vessel and the mooring buoy. Working practice for the mooring operation 5.20 The mooring equipment e.g. shackles, anchor chain and the required tools are heavy items. The mooring gang crew would need both the physical strength and team work to complete the mooring operation in a short period of time. There is always a danger that the ship s residual speed may cause the tilting of the mooring buoy and lifting of mooring eye shackle. Existing working practice requires the crew to complete each individual task on the buoy and return to the launch as soon as possible. According to the mooring gang crew, in case of buoy tilting and lifting of mooring eye shackle, the mooring crew would either jump into water or onto their pilot boat to escape. It appears that the mooring procedures need to be reviewed by relevant parties, in particular the necessary safety precautionary measures to be taken. 20
Cause of death 5.21 The head of the Sailor A was crushed by the mooring eye fitting which support the chain cable with a total weight of about 6.7 metric tones. He died of multiple injuries due to crushing and grinding effects between the mooring eye fitting and the buoy. 21
6. Conclusions 6.1 An accident happened at the government mooring buoy A43 on 6 April 2007. While a mooring gang of three were standing on the mooring buoy to secure the anchor chain of the Vessel to the buoy, the mooring buoy was suddenly tilted and the mooring eye fitting was lifted up from its cylindrical trunking. Two of the mooring gang crew fell into the water while the other fell and was trapped in the cylindrical trunking of the mooring buoy. The latter was crushed to death by the mooring eye fitting. 6.2 The investigation revealed that the Vessel was in motion and moved away from the mooring buoy after the mooring gang crew had secured the ship s anchor chain to the buoy. As a result, the mooring buoy was tilted and the mooring eye fitting was pulled out from the cylindrical trunking of the buoy. 6.3 The investigation has also identified the following contributory factors to the accident: The buoy mooring operation poses significant inherent risks to the mooring gang crew. They are required to remain on the mooring buoy for a prolonged period; Excessive discrepancy on the settings of propeller pitch angles existed between the local position and the bridge control console. The propellers still produced thrust even the pitch control was put to zero ; and Poor communication among the working teams during the mooring operation. 22
7. Recommendations 7.1 A copy of this report should be sent to the Master, the Management Company of the Vessel, the Pilot, the Association and the Weal Ocean Limited advising them the findings of this incident. 7.2 It is recommended that a working group formed by the Association, Weal Ocean Limited, Pilotage Unit and Mooring Unit of Marine Department to review the working procedures for the mooring operation with an aim to reduce the risk level of the mooring gang crew. 7.3 The Association and the Weal Ocean Limited is to be reminded to take necessary steps to enhance the safety awareness of the mooring gang crew safety. 7.4 The Master and the Management Company is to be reminded to ensure that: Propeller pitch indicators should be check periodically for accuracy; and To take necessary steps to enhance the effective communication arrangements between parties during mooring operation. 23
8. Submissions 8.1 In the event that the conduct of any person or organization is criticized in a casualty investigation report, it is the policy of the Hong Kong Marine Department that a copy of the draft report is given to that person or organization so that they have the opportunity to rebut the criticism or offer evidence not previously available to the investigating officer. 8.2 The final draft report was sent to following parties for their comments: a. The Management Company of the Vessel b. The Master of the Vessel c. The Chief Engineer of the Vessel d. The Chief Officer of the Vessel e. The Pilot of the Vessel f. The Hong Kong Pilot Association Limited g. The Weal Ocean Limited h. The Coxswain of the Pilot Boat i. The Engineer of the the Pilot Boat j. The Sailor of the Pilot Boat 8.3 Comments were received from the Hong Kong Pilot Association Limited, no submissions were received by other parties. The final draft report has been amended as appropriate. 24
Appendix Working procedures from Weal Ocean Limited 25
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