Battle of FSB Mary Ann - Background and Base Construction

Background and Base Construction

FSB Mary Ann was initially established on 19 February 1970 by elements of the 1st Battalion, 46th Infantry (part of the 196th Light Infantry Brigade (196th LIB)). At the time it was not intended to be a permanent base, and was closed by the same Battalion about two months after it was opened. Operational needs brought the 1-46th Inf back to Mary Ann on 27 June, and the base was put back into operation. According to one Battalion commander it was a poor location for a firebase from a defensive standpoint. " in a saddle with hills around it on three sides." It was also at the very edge of helicopter range from Americal headquarters at Chu Lai. Any other location in the region would have put the FSB outside the range of the Division's heavy artillery batteries and prevented artillery at Mary Ann from shelling key locations in the region. From an offensive standpoint the FSB was in a good location since it straddled the Dak Rose Trail network.

FSB Mary Ann's construction was no different from many other U.S. firebases in South Vietnam. Running northwest to southeast, the firebase stretched 500 meters along the crest of a 200 meter high ridge connecting two hillsides. Only 75 meters wide at its narrowest point, Mary Ann widened to 125 meters at the northwest and southeast ends. A trench, "knee-deep in certain stretches and waist-deep in others" defined the base's perimeter and connected the base's twenty-two bunkers. Like any typical late-war FSB, most of Mary Ann's bunkers were made from converted metal shipping containers known as conexes. In addition to the conex bunkers, Mary Ann had over thirty assorted structures (hootches, sandbagged bunkers, and other makeshift structures). The southeast end of FSB Mary Ann housed the Battalion Tactical Operations Center (B-TOC) and Company Command Post (CP), both located next to a small VIP helipad. The base's mess halls, a communication center, the Battalion aid station, ammunition bunkers, storage for general supplies, and two artillery firing positions were also located at this end of the FSB. The northwest end of the base housed a second artillery position with two 155mm howitzers, the fire direction center and the artillery command post. The saddle between the two ends of the FSB served as the resupply helipad. Dirt roads divided both ends of the base, and also ran outside the wire at two points: southwest past a firing range to the spring that served as the base's water point and northwest to the trash dump.

Soon after being reopened, FSB Mary Ann was probed many times (four attempts are recorded between July and August of 1970) and one author states that the base could have been easily observed from the high ground surrounding its location. The last major contact in the area was a firefight on 13 August, when Company A, 1-46th Infantry hit and overran "what was probably the NVA command post for the area." After that firefight, organized resistance seemed to cease. That quiet, combined with the usual cycle of replacements at all levels of American units (from individual riflemen to the Company and Battalion commanders), led to what the outgoing Battalion commander called an "awfully complacent" mindset.