The correct answer is A) tap the bulkhead with a hammer to check for a water level. To determine if a compartment has flooded, the proper procedure is to tap the bulkhead with a hammer to listen for a change in the sound. A hollow, dull sound indicates the compartment is flooded, while a sharp, metallic sound indicates it is dry. This is the recommended method because it allows you to assess the water level without having to open the hatch, which could further flood the compartment. The other options are incorrect because: B) feeling the bulkhead for heat would not indicate flooding, C) opening the hatch dogs on the side away from the hinges would not provide any information about the water level, and D) opening the watertight door could lead to additional flooding if the compartment is indeed flooded.