Factual error: When the ballast tank valves open, they open by dropping down, which would be impossible with the pressure of the water pressing against it. Regardless of the domino effect of the water flowing, it's tremendous pressure.
Ian Hunt
18th Feb 2008
Poseidon (2006)
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Suggested correction: It's actually very much possible. These PRV are designed to open when the pressure in the tank reaches a certain setting, which is equal to or slightly higher than the max design pressure of the tank. Plus, a gate valve of that size can only be operated with hydraulic oil plungers, capable of generating 150+ bar to lift the valve in a normal operation. Since the ship is upside down, the valve slides down; the weight of the valve then would require less hydraulic pressure to open.