Bulkhead and shell plating renewal, afloat

1. 01

   Challenge

   Class had recorded diminution beyond allowable limits on transverse bulkheads 3, 4 and 5, with associated wastage in the adjacent shell plating. The condition of survey required rectification before the vessel could continue trading, and the nearest available dock slot was eleven weeks out. The owner's exposure was therefore not the cost of the steel but the prospect of the vessel sitting idle, or trading under restriction, for most of a quarter.

2. 02

   Corvaden response

   Corvaden attended within the mobilisation window and surveyed the full extent of wastage rather than the members listed on the condition alone, on the basis that opening staging twice costs more than measuring once. Thickness readings were taken across all three bulkheads and the adjacent shell, and a renewal boundary was proposed to class covering approximately 20 MT of AH36. The proposal established that the work could be executed afloat, alongside, with no requirement for dock time.

3. 03

   Execution

   A crew of seventeen mobilised: project engineer, repair foreman, eight certified welders, five steel fitters and two safety officers, with riggers drawn as required. Work proceeded under the terminal permit system with continuous atmosphere monitoring in the affected tanks and a fire watch maintained after each shift. Plate was cropped and renewed in sequence to preserve structural continuity, welded to approved procedure specifications, and subjected to ultrasonic and magnetic particle testing. Renewed boundaries were air-tested and coating was reinstated within the worked areas.

   proj-bulkhead-and-shell-renewal-afloat-021200 × 800

4. 04

   Result

   The condition of survey was discharged with the vessel alongside and no dock booking taken. Wastage found outside the agreed boundary during the work amounted to a further two members; it was reported, priced and agreed before cutting, and appears on the final account as a stated variation rather than as an adjustment. The vessel sailed on her original schedule.

   proj-bulkhead-and-shell-renewal-afloat-031200 × 800

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