Your bulkhead is punctured below the water line and is taking on water, what should you do first?

The recommended first action when there is a punctured bulkhead below the waterline that is taking on water is to stop or slow the influx of water into the vessel as quickly as possible. This could involve jamming something into the breach to create an emergency seal to prevent further flooding. Taking immediate action in this way can help to safeguard the vessel and buy time for further emergency measures to be taken, such as notifying the captain or organizing an evacuation.

While notifying the captain and other actions like sealing all other bulkheads are important, they may take time that is critical in a flooding situation. The priority must be to mitigate the immediate risk of water entering the vessel, making the action of jamming the breach the most urgent and appropriate response to the problem at hand.