Case study
Ballast piping renewal by riding squad, under way
Renewal of approximately 140 metres of ballast line in No. 2 and No. 3 topside tanks, executed on passage by an embarked riding squad.
Identification
Quantities
- Pipe renewed
- 140 m
- Tanks
- No. 2 and No. 3 topside
- Mode
- Under way
- Squad
- 6
- Testing
- Pressure test
- 01
Challenge
Ballast line in the topside tanks had reached the point where leakage was affecting the vessel's ability to control heel during loading, and the defect had been carried on the work list for two dockings. Executing it in port meant either extending a call or booking dock time for what is fundamentally a pipe job. Executing it at sea meant confined space entry and hot work under way, which the owner's technical department was not prepared to authorise on assurances alone.
- 02
Corvaden response
Corvaden proposed a riding squad and submitted the method statement, risk assessment and permit arrangements for approval before mobilisation rather than on boarding. The submission set out which sections could be renewed under way and which could not, and stated plainly that the two runs passing through a bunker tank boundary would be left for a port call. Scope was agreed against that boundary before the squad embarked.
- 03
Execution
Six technicians embarked at Santos. Spools were prefabricated ashore from dimensional survey taken during the port call and carried aboard, which removed the majority of hot work from the passage. Entry to each tank was made under the vessel's own permit system with atmosphere testing, an attendant at the access and rescue arrangements in place. Remaining welds were carried out under permit issued by the Master with a fire watch maintained. The squad reported daily in writing to the Chief Engineer and to the owner.
proj-ballast-piping-renewal-under-way-021200 × 800In progress - 04
Result
Approximately 140 metres of line was renewed and pressure tested on passage. The defect came off the work list without a port call or dock time being taken against it. The two runs excluded at the quotation stage were recorded, with the reason, in the handover pack at disembarkation, and remain on the work list rather than having been quietly absorbed or quietly dropped.
proj-ballast-piping-renewal-under-way-031200 × 800As repaired
Response in 6 hours. Mobilisation in 48 hours.
Send the repair specification, the class report and photographs with the first enquiry. Scope confirmed against documents is scope that does not change on arrival.