[43] There is an interesting possibility as to why the mortars in the Horseshoe were never silenced. Fourteen years earlier, at Dien Bien Phu, the North Vietnamese used an ingenious method to protect their heavier siege mortars from air attacks and they may well have repeated it at Khe Sanh. The mortar crews selected a site on the slope of a hill, figured the elevation and deflection necessary to hit one specific target, and then dug a small tunnel at that precise angle into the side of the hill. The mortar was emplaced at the bottom of the tunnel with connecting caves which housed the gunners. When fired, the mortar rounds traveled up the shaft, sometimes as far as 50 feet before reaching the surface. The foliage was cleared away from the mouth of the tunnel so that the rounds did not hit the overhanging branches and detonate prematurely. Mortars emplaced in this manner were, of course, limited to only one target and, as far as the gunners in the Horseshoe were concerned, that target was 881S. When the siege was later broken and Marine units began to maneuver in the terrain surrounding the hill mass, they were never taken under fire by the 120mm mortars even though they did receive fire from smaller caliber weapons. Hill 881S, however, continued to be hit periodically by the 120mms. [44] Of all the jettisoned loads, those containing water were the most spectacular. On one occasion, a CH-46 carrying plastic containers of water was forced to release the net about 200 feet above the ground. The containers broke open in midair and the contents cascaded on the hill below. The Company E, 2/26, commander, Captain Breeding, later recalled that it produced one of the prettiest waterfalls he'd ever seen. [45] It is no exaggeration to say that MAG-36 helicopters played a decisive role in the battle. The maintenance of the hill outposts was imperative if Khe Sanh was to be held, and these units depended on the helicopters for survival. [46] During one period of extremely bad weather, the platoon from A/1/26 which held positions on Hill 950 went without resupply for nine days and the water shortage became a major problem. Lieutenant Colonel Wilkinson authorized the platoon commander, Second Lieutenant Maxie R. Williams, to send a squad out to a small stream which was about two hours march from the perimeter. In addition to finding water, the Marines surprised a group of North Vietnamese and killed nine of the enemy. One Marine was also killed. [47] Bad weather occasionally precluded the immediate evacuation of casualties from the hill outposts. PART VI SUPPORTING ARMS AND INTELLIGENCE