Diving Swimming Pool

In the competition, when diving in the pool?
Does the depth of immersion has any significant advantage for a swimmer? If so, Is there a technique for controlling how the depth of immersion?
It's been a while since I swam or coach, but the technique is called a dive hole. The purpose of the block was starting to dive to the flags of the pool. When he reached his highest point her hips and kicked the head angle down. As soon as youi hit the water that arched her back and their drive to "triggers" that to the surface. Do not go too deep, but not try to achieve water once or that kill your momentum.
John smith bomb in to swimming pool from top diving board