What is a primary method to check a bulkhead for flooding?

Tapping on the bulkhead and listening for a change in sound is a practical technique to assess the integrity of the structure. When you tap the bulkhead, the sound produced can indicate whether there is an air pocket or if the space is filled with water. A hollow sound can suggest that the bulkhead is dry, while a dull or muted sound may indicate the presence of water, suggesting potential flooding. This method relies on the principle that water and air produce different acoustic responses when struck.

The other methods listed may provide helpful information but do not directly confirm the presence of water in the same way. Observing for physical damage or leaks may indicate potential problems but does not provide clear evidence of flooding. A water level gauge is effective for monitoring water levels but may not be feasible in all scenarios, especially if the bulkhead is not readily accessible for installation or reading. In this context, listening for changes in sound after tapping the bulkhead offers a straightforward and immediate approach to detect flooding.