Which tool is essential for checking the integrity of a bulkhead?

The essential tool for checking the integrity of a bulkhead is a sounding rod. A sounding rod is specifically designed to gauge the level of water in various compartments and can help determine the condition of the bulkhead by identifying any potential leaks or breaches. By inserting the sounding rod into spaces near the bulkhead, personnel can assess whether there is water intrusion, which directly indicates the integrity and watertight status of the structure. This process is crucial for maintaining the safety and operational capabilities of a vessel, particularly during damage control situations.

While other tools listed may serve their own important functions in different contexts—such as measuring distances, detecting sounds, or measuring pressure—they do not have the same direct application for evaluating the condition of a bulkhead. The sounding rod’s specific utility in flood detection makes it the most appropriate choice for this particular task.