Department of Defense Photo (USMC) A374027
Two Marine enlisted men from Battery K,
3d Battalion, 11th Marines clean their 105mm howitzer. The battery position is
located on Combat Base Baldy in March 3970. The sign above the ammunition bunker
door reads 'No Smoking Within 50 Yards.'
lars combined with a night observation device and a laser rangefinder.* Using the IOD, a trained operator could sight a target at maximum range, of about 30, 000 meters in daylight and, employing a supplementary xenon searchlight, 4, 000 meters at night. He could identify the target and accurately establish its distance and direction from the OR Combining the ability to provide exceptional range and an azimuth accuracy with a digital computer to prepare firing data, the batteries could 'fire for effect' on the first volley, thereby eliminating the usual registration rounds which warned the enemy to take cover, while producing a 70 percent probability of first round hits. Colonel Ezell called the IOD the 'missing ingredient as far as good fire support was concerned .... We were losing targets because during the adjustment phase while we were trying to bracket them they were jumping in holes.' The IOD, he continued, 'with its ability to give us the first round hit... was just what we needed.'10
To operate the lODs, the 11th Marines selected its best forward observers, gave them special training with the S-2 section in use and maintenance of the instrument, and kept them at the same OPs for periods of up to five months. Constantly scanning the same countryside, observers learned every twist and turn of the enemy trail networks and spotted every tree line and bunker where the enemy customarily ran for cover from artillery fire. The more proficient observers could call in fire so as to 'lead' a moving enemy column. Even when the regiment displaced an IOD to a new position, it usually left the observer team behind, to continue watching the same terrain by other means.'
The IOD observation posts were credited with causing impressive North Vietnamese and Viet Cong casualties. On 2 January 1970, the IOD on Ryder spotted 25 NVA in Antenna Valley; answering the call for fire, Battery I, 3d Battalion, 11th Marines killed an estimated 20. Eight days later. Battery G of the same battalion claimed 11 enemy killed of 50 sighted by the Hill 425 IOD. On 31 January, the Ryder IOD called for fire on 40 more NVA, and Battery I responded, claiming 21 killed. During 1970, lOD-directed fire ac-
* The IOD was a product of the Marine Corps Special Procedure for Expediting Equipment Development (SPEED) project, administered by HQMC and the Marine Corps Development and Education Center. The purpose of speed was 10 respond more quickly than could regular research and development procedures to special requests for new equipment for Vietnam. Production and initial delivery of the IOD, a combination of three existing devices, took about six months. Of the first 10 made, four went to the Army in Vietnam and six to the 11th Marines. For additional details on SPEED, sec FMFPac, MarOps, Jan-Feb71, pp. 37-39.