Who is Everett Barrett from Rogue Warrior and what is their importance?

Everett Barrett is Richard's chief petty officer when Richard is in the Second Platoon of the UDT-21. Everett Barrett is an explosives ordnance specialist, and lost a finger playing with explosives. He curses a lot and is quite rough with his men. Barrett makes the men work hard, including Richard, but also gives Richard a role model. Under the leadership of Barrett, Richard decides to go to Officers Candidate School. Barrett is Richard's first and best mentor, or sea-daddy.