Complex sentence: It has served since its inception under the operational control of Commander, Submarine Force, U.S. Pacific Fleet (COMSUBPAC), and was originally established to support the Fleet Ballistic Missile (FBM) submarines and their tenders.
Split into simpler sentences: It has served since its inception under the operational control of Commander, Submarine Force, U.S. Pacific Fleet (COMSUBPAC). Originally established to support the Fleet Ballistic Missile (FBM) submarine and their tenders.