What is an appropriate action to take immediately after detecting a water ingress?

The appropriate action to take immediately after detecting water ingress is to seal the breach with tools. Taking prompt action to address the source of the water entry is critical to prevent further flooding and mitigate potential damage to the vessel. By sealing the breach, whether it's a crack, hole, or a compromised section of the hull, immediate efforts can be made to stabilize the situation.

This action should be prioritized because addressing the source of the ingress can significantly reduce the immediate risk of flooding progressing into a more severe situation. This proactive response helps maintain the vessel's buoyancy and structural integrity, which are essential for safety at sea.

While the other actions may be relevant in different contexts or stages of response to a water ingress incident, sealing the breach is the most immediate and life-saving measure. Limiting crew movement may help maintain order and avoid accidents, but it does not directly address the cause of the flooding. Starting to bail out water or initiating emergency flooding procedures could also be important steps, but they generally come after the initial control measure of sealing off the leak to prevent further ingress.