FSB's were a major US innovation in Vietnam. They were established as a self-contained and self-defended artillery base from which infantry operations could be mounted and supported.A typical FSB could be expected to deploy 6 x M102 105mm field howitzers and anything from a company to a battalion of infantry with it's supporting 81mm mortars, communications, medical and administrative personnel.Construction and Layout of American FSBThere was a standard drill for the construction of a FSB.following recon and site selection, a stake was positioned at the center of the chosen site and a 131' (40m) rope was used to mark the bunker line. the bunker line was marked by stakes at 15' intervals to indicate the individual infantry bunker positions. a circle of 246' (75m) radius marked the line of the perimeter wire. at each bunker position, helicopters dropped a standard pack of 1 shaped demo charge, 2 sheets of pierced steel planking and empty sandbags which were used to construct a 9' (2.7m) bunker. bulldozers excavated ground for the CP and the FSCC or FDC and pits for the guns and mortars. a prefabricated 20' (6m) observation tower was flown in by CH-47 time taken for construction varied but it was deemed essential that the outer defences and infantry positions were completed by last light on the first day of the occupation of the FSB site.
Legend1.FSCC - Fire Support Co-ordination Center 2.CommunicationsCenter3. Administration & Stores 4.105mmGunPits5.81mmMortarPits6.ObservationTower7.CommandPost8.GroundSurveillance&Anti-personnelradaremplacements9.Nightobservationdevices,searchlightsforvisible/infra-redillumination10.Perimeter-tripledannartbarbedwire,claymores,tripflares&Fougass11.InfantryBunkersL.Z. Landing Zone (Helicopters)