Tug TNS Catcher Capsizes While Turning a Box Ship off Busan, Leaving Six Missing
Investigators believe towline tension overwhelmed the 286-tonne tug during a course change
One seafarer has died and six remain missing after the tug TNS Catcher capsized while assisting a container ship off Busan.
The 286-tonne tug overturned at around 13:29, about nine kilometres east of Oryukdo, while working with two other tugs to manoeuvre the MSC Ikaria VI, a 5,576 teu Liberia-flagged container ship. Of the eight people on board, one Indonesian crew member was rescued. A South Korean seafarer was recovered unconscious and later died in hospital. Six others remain unaccounted for.
Investigators believe the tug may have been overwhelmed by towline tension while changing course. Busan Coast Guard said two tugs were pulling from either side of the container ship's bow while a third pushed from the stern. TNS Catcher, positioned on the starboard bow, was turning to starboard when it rolled sharply to port and capsized.
Officials believe the vessel's speed and timing may have been mismatched during the manoeuvre, although it has not been confirmed whether the tug became snagged on the towline. A collision with the container ship has been ruled out. CCTV footage from the container ship shows TNS Catcher beginning the turn before rolling over.
The tug later sank and has been located at a depth of around 87 metres, 6.5 kilometres east of Songjeong Port. Poor underwater visibility has hampered a navy remotely operated vehicle search.
The coast guard has expanded the search area to 66 kilometres by 40 kilometres, deploying 24 vessels and seven aircraft. A 41-strong investigation team has secured AIS, VDR and CCTV data as authorities work to establish the exact cause.
Girting remains the characteristic way a harbour tug is lost. A tug made fast on the bow of a turning ship can be pulled beam-on faster than the master can react, and the righting moment that keeps her upright disappears once the towline angle passes a certain point. The evidence set the investigators now hold, combining voyage data from the assisted ship with fixed camera footage of the roll itself, is unusually complete for a casualty of this type.
