Marines were local Viet Cong or members of the inï¿½frastructure. As had been true for the past year, mines and boobytraps caused a large proportion of the regiï¿½ment's casualties, although the Marines now were rindï¿½ing and disarming a monthly average of 75 percent of the mines they encountered.18
On 3 January, the 1st Marines reorganized its Quick Reaction Force (QRF). A regimental order of that date required each battalion, in rotation, to furnish one rifle company to serve, usually for 15 days, as the 1st Marines' QRF. One platoon of the QRF company, unï¿½der operational control of the regiment, would be billetted at the 1st Marines' CP on Division Ridge ready for deployment by helicopter anywhere in the regimental TAOI on 15 minutes notice. The rest of the company was to be prepared to reinforce the QRF platoon by helicopter within one hour of an alert. An aircraft package for the QRF of one UH-lE, three CH-46s, and two AH-1Gs would stand by at Marble Mountain. The principal mission of the QRF was to reinforce reconnaissance units and exploit intelligence reports.19
During January, the 1st Marines employed its QRF four times, twice in response to current information, once to protect a downed Army helicopter, and once to assist a reconnaissance team engaging the enemy. The following month, the quick reaction platoon twice worked with infantry companies in surprise sweeps and searches of suspected enemy headquarters and base areas. None of these reactions resulted in significant contact.20
In mid-January, in response to reports of the eneï¿½my buildup for the K-800 Campaign, the 1st Marines intensified efforts to prevent rocket launchings against Da Nang. On 13 January, and again after the offenï¿½sive had begun, on 8 and 22 February, the regiment directed its battalions to concentrate patrolling on previously used rocket launching sites and frequently travelled infiltration routes from Charlie Ridge toward the lowlands. Early in February, the 1st Battalion, 1st Marines was temporarily reinforced by Companies A and C of the 5th Marines for antirocket activities. The 1st MAW increased aerial surveillance of the Rocket Belt, and the 11th Marines redeployed its Integrated Observation Devices (lODs) for better coverage of potential enemy firing positions.21
Supplementing these regular antirocket measures, the 1st Marines began a preemptive search and desï¿½troy operation on western Charlie Ridge. In this operation, patterned on Imperial Lake, the 1st Marines employed continuous reconnaissance and infantry patrolling and concentrated air and artillery attacks in an effort to locate elements of the 5 75th NVA Arï¿½tillery/Rocket Battalion and to prevent the NVA and VC from using the Charlie Ridge base area to prepare for attacks against Da Nang.
The operation, codenamed Upshur Stream, began on 11 January under the control of Lieutenant Colonel Robert P. Rose's 1st Battalion, 1st Marines. On the 11th, a platoon of Company D was inserted by helicopter on Hill 383, about five miles northeast of Thuong Due. The platoon secured the hill as a patrol base for teams from the 1st Reconnaissance Battalion which were searching the surrounding rough. Jungle-covered terrain. Two days later, at 1300, a 1st Battalion comï¿½mand group, with Company B of the 1st Battalion, landed from helicopters on Hill 383. The infantry took over the search of the area, relieving the reconnaisï¿½sance teams. On the 15th, two 4.2-inch mortars and crews from the 1st Battalion, 11th Marines were lifted to Hill 383 by helicopter to furnish fire support. The Marines systematically patrolled the hills until 23 Januï¿½ary. They found a few abandoned base camps and small caches of weapons, ammunition, food, and equipment. Many of the weapons they captured were rusty and long-unused. The Marines found no major rocket storage areas or enemy troops.
Most of the Marine casualties in the operation ocï¿½curred on 20 and 21 January. As a platoon of Compaï¿½ny B was patrolling about two miles west of Hill 383 on the 20th, the point man set off a boobytrap made from a can filled with C-4 explosive. The blast injured four Marines. A second C-4 can boobytrap blew up as the platoon was securing a landing zone for a medï¿½ical evacuation helicopter wounding another four men. The helicopter arrived to pick up the casualties, and as it settled into the landing zone, its rotor wash detoï¿½nated four additional mines and wounded three more Marines. Company B's misfortunes culminated the next day, when a CH-46D from HMM-463 crashed and burned while landing at the company's position. Four Marines, a Navy corpsman, and a Kit Carson Scout died in the wreck; 16 other Marines were inï¿½jured, 10 seriously.22
On 20 January, the division ordered the 1st Marines to extend Upshur Stream indefinitely as a combined reconnaissance-artillery-infantry campaign. The new phase of the operation began with a concentrated arï¿½tillery attack by the 1st Battalion, 11th Marines. On the 21st, four self-propelled 155mm howitzers of the