See unitsDeck equipment and machinery: winches, cranes, hatches, watertight doors, pilot ladders and gangways
Watertight doors: closing, local controls, alarms and drills
1The lesson in plain words
Watertight doors keep flooding in one compartment. Keep them closed at sea unless allowed, and never try to pass a moving sliding door.
Why they matter
Watertight bulkheads divide the hull into compartments, so flooding stays in one place. A door in such a bulkhead is only as good as its closing: an open door lets a flooded compartment fill the next. SOLAS keeps watertight doors closed at sea unless the ship’s approved procedures allow one open for passage or work. Then it is closed again as soon as you are through or the work ends.
Types
A hinged watertight door is closed by dogs, levers round the frame that press it onto its seal; close them all, not just a few. Sliding doors move sideways in a frame and are worked by hand or by power. Passenger ships use power-operated sliding doors, and many cargo ships have them in engine rooms and tunnels.
Power sliding doors
On passenger ships (SOLAS II-1/13), all power-operated sliding doors close together from a bridge console within 60 seconds. Each door closes at an even rate in 20 to 40 seconds. When closed remotely, an audible alarm sounds 5 to 10 seconds before the door moves and continues until it is shut. Each door has local controls on both sides, and a hand mechanism closes it within 90 seconds. The bridge shows whether each door is open or closed.
Passing through
In bridge doors-closed mode, the door closes again when you release the control. Use the posted instructions and local controls to open the door fully. Keep it fully open throughout passage, transferring from the near-side OPEN control to the far-side control as trained. Release only when everyone and anything carried are clear. Get another trained person to help carry a toolbox or other load. Never enter a closing door, try to beat its alarm or block it open.
Drills and defects
On passenger ships, watertight door drills are held weekly, and doors in main bulkheads in use at sea are operated daily. Report a door that is slow, noisy or will not close, a damaged seal, or a failed alarm or indicator.
2Key data
- All doors from bridge
- Closed together within 60 s, ship upright (passenger ships)
- Each power door
- Closes at an even rate in 20–40 s
- Alarm on remote closing
- 5–10 s before movement, until fully closed
- Hand closing
- Within 90 s, from either side and from above the bulkhead deck
- Passenger ships
- Drills weekly; doors in use at sea operated daily
3Key points
- 1
Watertight doors keep flooding in one compartment; keep them closed at sea unless allowed.
- 2
Hinged doors: close every dog. Sliding doors: hand or power operated.
- 3
From the bridge, all power doors close within 60 s; each takes 20–40 s.
- 4
An alarm sounds 5–10 s before a remotely closed door moves; local controls are on both sides.
- 5
Open fully; keep the opening controls operated throughout passage; release only when everyone and anything carried are clear.
4Frequent mistakes
Wrong: Wedge a sliding watertight door open while you carry tools back and forth.
Right: Never block it. Open fully and keep the opening controls operated throughout passage. Get trained help with loads; release only when everyone is clear.
Wrong: On a hinged watertight door, two dogs are enough for a short trip.
Right: Close every dog. A partly dogged door leaks under pressure and may burst open.
Wrong: When the alarm sounds you have time to slip through before the door shuts.
Right: Never try to beat a closing door. Step back, wait for it to close and open it again by the local control.
5Practice case & exam keys
You are carrying a toolbox through a power-operated sliding door on a passenger ship at sea. Halfway through, you accidentally release the local control and the door starts closing.
Show the answer
Use the local OPEN control at once to reopen the door fully and keep it open while you get clear. Do not try to outrun it or drag the toolbox through. Get another trained person to help with the toolbox. Keep the opening controls operated, transferring between sides as trained, until everyone is clear, then release.
Exam keys
- Watertight doors closed at sea unless procedures allow; close after passage or work.
- Passenger ships: all power doors closed from bridge within 60 s; each 20–40 s; alarm 5–10 s before movement.
- Local controls on both sides: hold OPEN throughout passage, release when clear; hand closing within 90 s; bridge indication.
- Never pass a moving door. Hinged doors: all dogs. Passenger ships: drills weekly, doors operated daily.
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