The container ship Milano Bridge did not reduce its speed as it approached a pier in Busan New Port on 6 April 2020, causing it to knock into and demolish a gantry crane, investigations showed.
South Korea’s Ministry of Oceans and Fisheries (MOF) said on 7 May that the accident happened when the 13,870 teu vessel, operated by Ocean Network Express (ONE), also had its propeller just touching the water surface, weakening the vessel’s manoeuvrability.
The MOF’s Korean Maritime Safety Tribunal’s (KMST) investigations showed that Milano Bridge entered the port with about one-third of its propeller exposed above the water surface because it was not carrying sufficient ballast water. Milano Bridge was ballasting at the time, having departed from Zhoushan DDW PaxOcean Shipyard in China, after undergoing repairs.
KMST noted that Milano Bridge sailed towards pier #2 at a speed of 8 knots, which was higher than the usual speed of 6 knots when berthing. Wind speed at the time was 5 to 8 metres per second, which is considered normal.
The vessel had grazed another container ship, Seaspan Ganges, before knocking into one of three gantry cranes along the pier.
Investigators also watched closed-circuit television footage of the accident, interviewed port pilots and ship captains, in addition to conducting field work.
The operations of Milano Bridge at the time of the accident were also simulated, using the voyage data and statements from related persons, as well as similar weather, tidal, and wind conditions.
The simulations showed that when the propeller is fully under water, the ship had better manoeuvrability and a lower risk of accidents.
KMST also calculated that the accident could have been avoided if Milano Bridge had slowed to less than 7 knots when approaching the pier.
KMST investigator Lee Chang-yong said, “We’re investigating to determine the accident cause and prevent a recurrence. Apportionment of responsibility will be done through a later review.”
The Milano Bridge is now undergoing repairs in Dalian Shipbuilding Industry Company’s yard in China.