Position Monitoring Inadequate Prior to Celtic Spirit Collision
The U.K.'s Marine Accident Investigation Branch (MAIB) has published its report on the cargo vessel Celtic Spirit anchor dragging incident citing inadequate position monitoring.
The vessel dragged her anchor during heavy weather and subsequently collided with the research and survey vessel Atlantic Explorer and the general cargo vessel Celtic Warrior, on the River Humber in March this year.
At the time, the visibility was poor, with intermittent snow blizzards. The wind was easterly at Beaufort force 8 to 9, and the sea state was moderate. All three vessels sustained shell plate damage, but there were no injuries and no pollution.
The report highlights the importance of ensuring taking tidal and environmental conditions fully into account when going to anchor and ensuring that the frequency and accuracy of position monitoring is commensurate with the conditions experienced.
The vessel dragged her anchor because insufficient anchor cable had been deployed for the tidal range and the environmental conditions. It was not immediately identified that the vessel was dragging her anchor because the position monitoring interval was inadequate. The watchkeeper did not alert Vessel Traffic Services or nearby vessels of the situation, and the crew were was unable to maneuver in time to avoid the collisions because the ship's engine was not on immediate readiness.
Celtic Spirit’s owner, Charles M. Willie & Co (Shipping) Ltd, has taken action with its fleet to raise the standards of anchor watchkeeping and to clarify the term “main engine stand-by.”
Details of collisions
At about 0246, Celtic Spirit began to drag anchor in a north-westerly direction. Nine minutes later, in preparation for the watch handover, the vessel’s 2/O looked at the radar screen and noticed that the distance to Atlantic Explorer had decreased. He plotted the vessel’s position on the chart, which verified that the vessel was dragging its anchor, and called the master. He also called the engineer in his cabin and ordered him to start the main engine, and he instructed the duty AB, via hand-held radio, to go forward and check the anchor cable.
At 0300, Celtic Spirit’s chief officer (C/O) arrived on the bridge to take over the anchor watch in accordance with the vessel’s watch rota. The 2/O informed the C/O that the vessel was dragging anchor, then went below to hasten the engineer. On the way, the 2/O met another AB, who was about to come on duty, and instructed him to go forward and assist with the anchor windlass.
When the 2/O returned to the bridge he noticed that the ship’s speed had increased to 0.9kt, and he was notified by the duty AB on the fo’c’sle that the anchor cable was tight.
At 0306, Atlantic Explorer’s bridge watchkeeper called Celtic Spirit on very high frequency (VHF) radio channel 16 and warned: “You are dragging directly to me, your anchor is not holding, your speed is 0.9 and you are going directly to me.”
Celtic Spirit’s 2/O acknowledged the call and advised that his engine was being prepared to start.
Atlantic Explorer’s bridge watchkeeper called his engine room and instructed the duty engineer to start the main engines. He also alerted the vessel’s master to the developing situation.
At 0308, Humber VTS called Celtic Spirit on VHF channel 16 and asked how long before its engine would be ready. The 2/O replied: “We are already preparing the engine; the engineer is in the engine room.”
When probed further by VTS, the 2/O predicted it would take five to 10 minutes to start the engine.
VTS then called Atlantic Explorer and asked if its engines were ready. The watchkeeper advised that they were not. VTS then warned that Celtic Spirit was dragging anchor and heading towards them. Atlantic Explorer’s watchkeeper replied: “Yes, I see. I call them already and they are really really close, I think they will hit.”
While waiting for control of the main engine to be passed to the bridge, Celtic Spirit’s C/O attempted to avoid the collision using the vessel’s bow thruster. As he was doing this, the master arrived on the bridge and took over control at the maneuvering position.
At 0310, VTS transmitted a warning to Celtic Spirit to advise that there was a risk of collision with Atlantic Explorer. Shortly afterwards, VTS called Atlantic Explorer and asked if any more anchor cable could be payed out. The bridge watchkeeper replied that six shackles out of an available seven had already been payed out.
At 0312, Celtic Spirit’s stern collided with Atlantic Explorer’s bow. At approximately the same time, Celtic Spirit’s engineer started the main engine and passed control to the bridge. The master engaged ahead propulsion but was unable to maneuver clear because Celtic Spirit’s stern was fouled on Atlantic Explorer’s anchor cable. VTS contacted Atlantic Explorer to request a damage report, and also mobilized a tug from Immingham.
By that time, Atlantic Explorer’s engines were running and in bridge control, but the vessel’s maneuverability was hampered by its anchor cable and Celtic Spirit. The entangled vessels were set by the wind and tidal stream, at over 3kts, towards Celtic Warrior, which was anchored two cables to the north-west. Celtic Warrior’s bridge watchkeeper had been monitoring the radio exchanges between VTS, Celtic Spirit and Atlantic Explorer, and had called the vessel’s master and crew.
At 0316, VTS called Celtic Warrior on VHF channel 16 and asked if the vessel’s engines were running. The bridge watchkeeper confirmed that they were. VTS then warned that Celtic Spirit and Atlantic Explorer were dragging anchor towards Celtic Warrior and advised the vessel to weigh anchor. Celtic Warrior’s master, who was on the bridge, immediately engaged astern propulsion but, shortly afterwards, at 0320, Celtic Spirit’s port quarter collided with Celtic Warrior’s bow. The impact caused Celtic Spirit to become detached from Atlantic Explorer’s anchor cable and all three vessels began to set to the northwest.