160m Bulk Carrier
Challenge
A fully laden bulk carrier was involved in a collision with two other vessels whilst entering anchorage at Johor, Malaysia. The bulbous bow of one vessel penetrated the side shell of the bulk carrier substantially below the waterline and subsequent flooding of No 3 & No 4 ballast tanks to port caused a list of 11°. It was stipulated by class (ABS) that a temporary repair was required to allow the vessel to proceed to a port of discharge and then to a shipyard in China for permanent repair. There were no dry docks available in the vicinity. The extent of damage was considerable and the main challenge was undertaking an afloat repair.
Solution
A SeaTec project manager was assigned to oversee the whole operation. An underwater inspection by SeaTec divers confirmed the hole was 4m x 4m and the owners and class agreed to construct a cofferdam of 6m x 5m to sit on the intact hull structure. The 5.6 tonne cofferdam was designed by UK based SeaTec engineers and built by local contractors. It was positioned by the dive team using the vessel’s crane and clamped in position using a total of twenty-nine steel screw dogs, most of which had to be welded to the hull plating underwater. The ballast tanks were then pumped dry after a suitable period, to guarantee the seals, staff were then able to enter the tanks for internal inspection. After fitting additional internal reinforcement bars ABS approved the temporary repair and the ship was able to depart for discharging 17 days after the accident occurred.