Exam Question

(a) Testing for Water Tightness:
Hose Test:  This involves applying a high-pressure water jet (2 bar from a distance of 1.5 meters, nozzle diameter at least 12mm) to the bulkhead's surface. This test directly checks for leaks. The test is typically done from the side where the stiffeners are attached.
Air Pressure Test:  An air pressure test applies pressure (0.2 bar) for about an hour, detecting leaks that may not be apparent during the hose test. This usually happens prior to the application of protective coatings.
Structural Test: Visual inspection, especially of welding joints, is carried out. Non-Destructive Testing (NDT) is done where necessary. Tanks designed to hold liquids, which form subdivisions of the ship, are tested for tightness with a water head up to the deepest subdivision load line or to a head of 2/3 the depth from the top of the tank to the margin line, whichever is greater.