M/V Borhan – Underwater Cracked Shell Plating Renewal

Ship's particular: Loa: 149.79m; B: 21.04m, D: 12.25m
Repair carried: Tianjin anchorage
Repair period: 4 days
Class: LRS

DESCRIPTION:
The ship was found one crack on shell plating IWO No.4 hold stbd where was around 2 meter under water level at Tianjin anchorage and meanwhile the ship was with cargo in No.1, 3 & 5 holds.

We had fabricated one cofferdam with size of 3m (height) x 1.2m (length) x 1m (width) and transported to anchorage by tugboat then the cofferdam was fixed around the crack area by ship's crane and the top area upper water level was welded to shell plating.

The lower part of cofferdam under water level was tack welded to shell plating by class approved underwater welding and the remained area was sealed by carpet/cotton to get the cofferdam watertight, then the seawater inside cofferdam was pumped out by submersible pump.

Cropped and renewed cracked shell plating by CO2 welding and carried out ultrasonic testing for welding seams in order as per class requirement.

Removed cofferdam by class approved underwater cutting and ground cutting area well then carried out underwater MPT testing for grounding area and found no cracks occurred.

All above-mentioned jobs and testing was approved & supervised by attending LRS surveyor.