Naval officers often refer to the "integrity of the hull." When a submarine comes out of dry dock, the first exercise is called a "sea trial," which takes the submarine to depth in the ocean to test the integrity of the hull. Naval personnel sometimes call this phase a "shakedown cruise" because it measures a vessel's performance and general seaworthiness. If integrity is compromised in anyway, such as a poor weld, the stress from the increased pressure of deep water will inevitably find that weakness.