Operational guide · Safety & equipment

Watertight Doors and Compartment Integrity

Watertight-door operation depends on ship type, door category and the applicable arrangement: SOLAS II-1/21–22 applies to passenger ships, while cargo ships follow II-1/13-1 and their approved configuration.

watertight doorsSOLAS II-1compartmentationsubdivision

Operational Explanation

The ship's watertight subdivision into separate compartments divided by bulkheads is the primary structural defence against sinking in the event of a breach: if a single section floods, the watertight bulkheads and the doors passing through them must prevent water spreading to adjacent sections. This defence only works if the watertight doors are actually closed when needed.

SOLAS II-1 Part B-2 includes construction requirements for subdivision and watertight integrity, including Regulations 13 and 13-1. Regulations 21–22 belong to Part B-4 and govern tests and operating conditions for the passenger ships concerned. For cargo ships check II-1/13-1, the approved damage-control configuration and installation manuals.

Regulatory Reference

SOLAS II-1/13 contains construction requirements for doors in passenger ships; II-1/21–22 contains related passenger-ship tests and operating rules. The 20–40 s, 60 s and 90 s times, alarms and central control apply to passenger doors within the cited provisions. Cargo ships follow II-1/13-1, approved damage-control arrangements, manuals and installation-specific requirements.

Safe passage: do not pass through a closing door. Open it fully and hold it open with the local controls under the ship’s instructions; releasing a control may trigger automatic closure in “doors closed” mode. Do not carry loads alone if they prevent safe operation of the controls. Familiarisation, displayed instructions and training must address the system actually installed. MCA MGN 35 Amendment 2.

Scope of Application

First determine ship category and door type. Do not automatically apply passenger-ship closing times, central control, tests and records to cargo ships.

Procedure / How to Complete It

Identify ship category, door and applicable SOLAS/approval provision.
For passenger ships carry out tests, closures and records required by II-1/21–22 for the relevant doors.
For cargo ships apply II-1/13-1, damage-control arrangements, manuals and installation requirements.
Record openings and closures only for the categories and conditions for which the rule or procedure requires it.

Practical Example

Example: before testing, identify the ship as passenger or cargo and the door category; then apply the relevant times, control and records without automatically importing a 60-second simultaneous test to a cargo ship.

What Typically Goes Wrong

Doors secured open or defective controls and alarms can compromise subdivision and personal safety. Do not defeat safety devices or enter a door’s travel path to test whether it stops.

Common Mistakes Mistake Library

Mistake	Consequence	How to avoid it
Door category and applicable rule not identified before setting its position at sea	A passenger-ship or category-specific provision is generalised to the wrong ship or door	Identify ship type, door category and approved arrangement; apply the opening and reclosing conditions prescribed for that case
Operational test performed without checking the parameters prescribed for that door	A failure or out-of-limit closing time may remain undetected	Measure times and functions where required by the applicable provision, manual or approved procedure
Records made under a generic rule for every opening	The log may be incomplete or burdened with entries that are not required	Record openings and reclosures under the categories and conditions required by II-1/22, the prescribed logbook and approved procedures

What the PSCO Checks

The PSCO checks the door and provision applicable to the specific ship. A central closing demonstration and its times apply only where the passenger-ship configuration and relevant paragraph require them.

Operational Tips

Don't treat opening a watertight door as a trivial operation: always reclose it immediately after passage.
Where required for the installation, time the simultaneous closing test, don't just verify that it completed.
Check the condition of the gaskets during the operational test, not just the closing mechanism.

Preparation checklist

Ship and door category identified
Applicable rule/approval identified
Passenger times and controls not imported automatically to cargo ships
Records limited to prescribed cases
Damage-control arrangements and manuals checked

FAQ

Do the 20–40, 60 and 90 second times apply to every door on every ship?

No. They concern passenger-ship doors within the cited provisions. Cargo ships follow II-1/13-1 and their approved configuration.

Must every opening always be logged?

No. Apply the precise categories and conditions of II-1/22 and the prescribed logbook, together with the ship's approved procedures.

Watertight Doors and Compartment Integrity

Operational Explanation

Regulatory Reference

Scope of Application

Procedure / How to Complete It

Practical Example

What Typically Goes Wrong

Common Mistakes Mistake Library

What the PSCO Checks

Operational Tips

Preparation checklist

FAQ

Related Topics