Watertight Doors and Compartment Integrity
Watertight doors left open during navigation defeat the entire logic of watertight subdivision: SOLAS Regulation II-1/22 requires them to remain closed at sea, with strictly limited operational exceptions.
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.
Chapter II-1 Part B-2 of the SOLAS Code governs subdivision and watertight/weathertight integrity; Regulation 22 requires watertight doors to remain closed during navigation, except for temporary opening for passage, with immediate reclosure.
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.
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
Common Mistakes Mistake Library
| Mistake | Consequence | How to avoid it |
|---|---|---|
| Watertight doors kept open during navigation for the convenience of frequent passage between compartments | Defeats the watertight subdivision in the event of sudden flooding | Always reclose immediately after passage, with no exceptions of convenience |
| Periodic operational test carried out only formally, without verifying the actual closing time | Malfunction of the remote closing system not detected until a real emergency | Actually time the simultaneous closing at every test, not just verify its completion |
| Opening not recorded in the bridge log because considered routine | Loss of traceability of which doors were open at a given moment, useful in an investigation | Systematically record every opening/reclosure, even routine ones |
What the PSCO Checks
Operational Tips
- Don't treat opening a watertight door as a trivial operation: always reclose it immediately after passage.
- Actually 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
Related Topics
Last substantive revision of this page: 20 August 2026 · page fingerprint 9e3f85a0a72c