A ship’s pipes carry vital fluids and gases necessary for the ship and its crew to function. Pipefitter apprentices learn how to install, inspect, and test the many piping systems on board aircraft carriers and submarines. They go through pipe theory, learn how to tack weld and braze and learn the basic skills necessary to function as a pipefitter. Pipefitter apprentices help to put the complex piping network together by cutting, bending, prepping and hanging piping runs on ships. They are required to install valves and make up flanges where required by the drawings. Testing crews operate and inspect the systems for leaks or flaws.