8-inch howitzer, maximum range 16, 800 meters, and the M107 175mm gun, maximum range 32, 000 meters. Each of these self-propelled weapons had the same type of tracked, motorized carriage, which simï¿½plified maintenance and supply for the Force Artillery batteries.5
In early 1970, Keystone Bluejay brought artillery redeployments and relocations. The 1st Battalion, 13th Marines left Vietnam during March 1970, following its supported infantry regiment, the 26th Marines. Battery K, 4th Battalion, 13th Marines and the 5th 175mm Gun Battery also departed. To fill in for the redeploying 13th Marines battalion, the 1st Battalion, 11th Marines moved its command post to the Northï¿½ern Artillery Cantonment, reassumed control of its own Mortar Battery, and moved 105mm batteries to NAC and Hill 10. Battery F, 2d Battalion, 11th Maï¿½rines displaced from An Hoa to Hill 55 to reinforce the 1st Battalion.
The basic 1st Marine Division operation order asï¿½signed the 11th Marines the mission of providing "defensive and offensive fires in support of operations within and beyond the TAOR, AO, and Reconnaisï¿½sance Zone" for Marines, other American Services, the South Vietnamese, and the South Koreans.6 In perï¿½formance of this task, the regiment's batteries respondï¿½ed to calls for fire from units in contact. They attacked actual or suspected enemy rocket and mortar positions. The Marine batteries expended much ammunition on "preemptive" and "intelligence" missions, formerly called "Harassing and Interdiction" and "Unobserved" fires* These were bombardments of known or suspectï¿½ed Communist base camps, infiltration trails, assemï¿½bly points, and supply caches. Many of these missions were carried out according to special fire plans to thwart periodic North Vietnamese and Viet Cong offensive "high points." As the tempo of ground comï¿½bat declined, missions fired in support of engaged troops diminished to a small proportion of the total amount of artillery fire. By August 1970, only about one percent of the 11th Marines' fire missions were conï¿½tact missions.7
In spite of the decline in contact missions, the 11th Marines continued to conduct a large volume of obï¿½served fire, mostly directed by the regiment's own obï¿½servation posts as part of a program to use artillery to supplement, and in some cases replace infantry patrols blocking enemy infiltration of the populated areas of Quang Nam. Colonel Ezell, who had instituted this effort after taking command of the 11th Marines late in 1969, declared:
It appeared to me that when we first went in, the inï¿½frastructure and the organized units were lying together in the coastal plains, and that the Marines, through offensive operations, had disengaged the organized units from the infrastructure, knocking them back to the west and to the hills .... Now the infrastructure had to remain ... to control the population. But they also had a great deal of dealing with the organized units .... It would appear if there was a disengagement that there must be ... a lot of travel back and forth across the battlefield by both the infrastructure and the organized units to perform their misï¿½sions. My artillery was not in position to control this. My F [orward] 0 [bserver] s were with the rifle companies, and they were certainly forward but they weren't observers in six feet of elephant grass.**8
In an effort "to destroy the enemy as far away as possible, to diminish his capabilities across the batï¿½tlefield to perform his mission," Ezell stated, "took 100 people out of my hide and we started a regimental OP system." These hilltop observation posts (OPs), each manned by a team of artillerymen and protectï¿½ed by reconnaissance or infantry elements, afforded a commanding view of the principal infiltration routes between the mountains and the populated area around Da Nang. An OP at FSB Ryder covered Anï¿½tenna Valley and portions of the Que Son Valley OPs on Hill 425 in the northern Que Sons and on Hill 119 overlooked Go Noi Island and the An Hoa basin, while others on Hills 200 and 250 in the northwestern Ariï¿½zona Territory and on Hill 5 5 dominated the Thuong Due corridor. Farther north. Hills 190 and 270, respecï¿½tively, commanded Elephant Valley and the routes leading down from Charlie Ridge. Artillery observers in these positions searched the countryside for enemy movement and called fire missions on promising tarï¿½gets, passing their requests through the appropriate fire support coordination centers (FSCCs).9
Six of these observation posts*** were equipped with the Integrated Observation Device (IOD). Introduced in late 1969, this Marine Corps-developed 400-pound instrument consisted of high-powered ships' binocu-
* The regiment ordered this change in terminology on 9 March 1970. 3/11 Jnl, dtd 9Mar70, in 3/11 ComdC, Mar70. * Colonel Ezell was relieved on 29 March 1970 by Colonel Ernest R. Reid, Jr. Reid in turn was replaced on 31 August 1970 by Colï¿½onel Edwin M. Rudzis. All three commanders followed the same artillery employment strategy.
** In April 1970, the six IOD positions were: Hill 270, Hill 200, Hill 65. Hill 119, Hill 425, and FSB Ryder. FMFPac, MarOps, Apr70, p. 4.