QUESTION 6.2.2

Cargo overboard and sea-suction valve isolation

Oil, ChemicalCargo Control Room, Pumproom, Main Deck

What is being checked

The inspector is checking whether every cargo-system overboard and sea-suction valve is closed, secured and verified before cargo transfer, and whether fitted leakage-monitoring and integrity-test arrangements remain effective.

Ready onboard

0/7 complete

PROCEDUREThe procedure covers sea-valve use, line displacement, isolation, leakage monitoring, testing and records.ISOLATIONRelevant valves are fully closed and secured by lockout, tagout, blanking or the approved equivalent before transfer.VERIFICATIONThe pre-transfer checklist and cargo log record independent confirmation of valve status.LEAK MONITORINGFitted pressure, vacuum or sampling arrangements are readable, accessible and checked for leakage.INTEGRITY TESTSea and overboard valves are tested between dry-docks at the approved pressure and interval.NOTICESClear anti-pollution warnings are posted at the valves and pump-operating position.CONDITIONValves, securing devices, blanks, gauges and test connections are in satisfactory condition.

Practice questions

Answer aloud, then open the preparation point.

1Show how cargo sea and overboard valves were secured before the current transfer.

Identify each applicable valve and the physical lock, tag, blank or approved indication, then match it to the signed checklist.

2How do you detect leakage past a closed sea valve?

Use the fitted pressure, vacuum or sampling arrangement from its safe reading point and explain the normal indication and escalation criteria.

3When was the last between-drydock integrity test and what pressure limit applied?

Show the approved test procedure, maximum permitted pressure, result, instrument details and defect closure.

4What precautions apply when taking ballast into cargo tanks or displacing a line with seawater?

Use the specific authorised procedure, verify valve alignment and containment, control cross-connection risk and record the operation.

5What would you do if leakage were suspected during cargo transfer?

Stop or suspend the operation as required, isolate the system, notify the terminal and Master, contain the risk and investigate under the emergency procedure.

Where an observation may arise

ISOLATION

A cargo overboard or sea-suction valve is not fully closed or not secured before transfer.

RECORDS

Pre-transfer verification or periodic leakage checks are not documented.

LEAKAGE

The monitoring gauge or sample indicates leakage past a valve.

TESTING

Between-drydock integrity testing is absent, overdue or performed above the approved pressure.

EQUIPMENT

A gauge, blank, securing device or leak-detection connection is missing or defective.

WARNING

Required anti-pollution notices are absent or the officer cannot explain the control.

Master's practical note

Physically verify the isolation boundary with the responsible officer. A ticked checklist is secondary evidence; valve position, securing method, blanking and leak indication must all tell the same story.

Equipment boundary and references

Equipment boundary: Valve design and approved isolation method vary. Do not pressure-test or manipulate cargo sea valves during operations outside the vessel's approved procedure and terminal agreement.

References

OCIMF SIRE 2.0 Question Library Part 1, Version 1.0, Question 6.2.2
MARPOL Annex I
ISGOTT, current edition
Vessel cargo and ballast system drawings

Last reviewed: 2026-09-08