Flooding Boundary Decision After Hull Breach
The ship has a second deck divided by transverse watertight bulkheads at frames 40, 48, and 56 and by a centerline longitudinal bulkhead. A collision has opened the shell plating in compartment 2S, frames 40 to 48 starboard. The watertight door in the frame 48 bulkhead is open, connecting 2S to compartment 4S, frames 48 to 56 starboard. A ventilation flap between 2S and 2P, frames 40 to 48 port, is also open. A ladder trunk in 2S has its watertight hatch to the third deck open. The damage control assistant reports a starboard list increasing from 2 to 4 degrees and no flooding in 2P yet. The frame 48 door can be closed from 4S; the ventilation flap can be closed from 2P; the ladder hatch can be closed from the third deck. A damage control party is standing by.
1. Which compartments are at immediate risk, and by what routes?
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Directly flooded: 2S, frames 40 to 48 starboard, through the shell breach.
At risk:
- 4S, via the open frame 48 door.
- 2P, via the open ventilation flap.
- The third-deck space, via the open ladder trunk hatch.
The centerline bulkhead and the frame 40 bulkhead bound 2S on the port and forward sides, so those are the containment boundaries. If the frame 48 door is closed, 4S is isolated. If the ventilation flap is closed, 2P is isolated. If the ladder hatch is closed, vertical flooding is stopped. Closures made after water has passed may trap water, but they still prevent further spread.
2. In what order should the closures be made, and from which side? Explain.
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Priority is to close from dry sides and stop the most dangerous spread.
- Ladder hatch to the third deck: close from the third deck if accessible. Vertical flooding adds free surface high in the ship and can capsize her.
- Frame 48 door: close from 4S, which is dry, to isolate 4S.
- Ventilation flap: close from 2P if 2P is still dry. If it can only be reached from flooded 2S, do not send anyone in; use a remote operator or accept 2P flooding and isolate it at its boundaries.
- Set boundaries at frame 40 and the centerline bulkhead, and post a watch.
Do not open any closure to 'check' without permission.
3. The list is 4 degrees starboard and increasing; 2P is still dry. Does closing the flap help or hurt, and what else do you consider?
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Closing the flap prevents 2P from flooding, which keeps the port side dry and may initially increase the starboard list because the starboard weight remains. That is still the right containment move: a deliberate, known list is safer than uncontrolled progressive flooding across the centerline.
The damage control assistant should calculate counter-flooding in port spaces low in the ship, not in 2P, and monitor list, draft, and free surface. If 2P later floods through another path, the list may reverse. The decision rule is contain first, then correct list with controlled counter-flood, and be ready to abandon the compartment. Report to the commanding officer and prepare to transfer fuel or beach if the list exceeds limits.