The process begins with a close range underwater explosion. If the steam void contacts the hull it will attach itself. In this location, the oscillation of the steam void will cause a cyclic stress to the submerged hull and weaken or breach it. If a submarine's pressure hull is compromised it is unlikely to survive. Explosion near submarine hull.
Depth charges are underwater bombs.
They are set to detonate at a prescribed depth. They must be dropped directly on the submarine to be effective. The primary goal in their use is not to sink the submarine, but rather to take it out of action. The ambient noise created by their use will generally deny the submarine the use of sonar. Furthermore, the shock wave may disable internal equipment that could take the submarine out of action.