March 18, 1969. Operation Dewey Canyon Concludes/Operation Report

Image: Operation Dewey Canyon Cover Page for Operational Report Summary

One of the most successful blows to Communist supply lines ever delivered by allied forces in the Republic of Vietnam ended at 1800, March 18, as the 9th Marine Regiment (Reinforced) of the 3rd Marine Division officially terminated Operation Dewey CANYON. Launched on January 22 into Communist strongholds north of the A Shau Valley, the multi-battalion operation unearthed the largest enemy munitions and arms caches of the Vietnam War. Five hundred and twenty-five tons of Communist weapons and ammunition were seized by the Marines in the mountainous, jungle area near the Laotian border. Among the 215 crew-served weapons captured and/or destroyed by the Leathernecks during the 56-day operation were 12 Russian-made 122mm field guns. These guns, capable of hurling a shell nearly 14 miles, are the largest enemy artillery pieces ever captured in Vietnam. In addition to the large guns, Marines uncovered numerous anti-aircraft guns with almost 27,000 rounds of ammunition and 1,126 enemy rifles – most of which were still in Chinese and North Vietnamese shipping containers. In addition, more than 45,000 grenades of various types, some 58,000 rounds of various-size mortar ammunition, more than 3,500 rounds of rocket and artillery ammunition and tons of small arms ammunition were captured. Among the various other types of ordnance the Leathernecks uncovered were 3,100 rounds of recoilless rifle ammunition, nearly 13,000 RPG rounds, and more than 5,000 pounds of explosives. The Marines' success during Operation Dewey Canyon did not come without enemy resistance. Operating in an area not previously entered by allied forces and long considered an NVA sanctuary, the Marines killed 1,355 enemy soldiers and captured 14. Marine losses were 121 killed and 616 wounded and evacuated. There were 187 other Marines with minor wounds. The 9th Marines, under the command of Col. Robert H. Barrow of St. Francisville, La., pushed into the upper A Shau Valley complex with relative ease during the initial stages of the operation. Fire bases Razor and Cunningham were established about 4.5 miles from the Laotian border to support infantry operations in the area. However, shortly after the Marines moved into the jungle, operations were temporarily curtailed by a nine-day period of bad weather. Consequently, most initial contact with the enemy was in small squad-sized actions. To offset the effect of the period of heavy inclement weather, Marine air planners developed special flying tactics prior to the opening phases of Operation Dewey Canyon. These proved invaluable during periods of heavy fighting when weather made close-air-support hazardous. Using the same radar-controlled system, Marine helicopters and fixed wing transport aircraft para-dropped supplies to the Leathernecks during the worst weather. The ability to keep the Marines resupplied was a major factor in the success of the operation. Marine helicopter pilots continued medical evacuation of the wounded throughout the operation despite the weather. Marine helicopters, flying under severe weather conditions, made more than 13,000 sorties while delivering in excess of 3,000 tons of supplies and carrying nearly 19,000 passengers while supporting the 9th Marines (Reinforced) on this operation. Although Marine jets were also hampered at times by the heavy monsoon weather, more than 560 sorties were flown by Marine aviators and 51 by Air Force pilots in support of the operation. These strikes resulted in 35 trucks, 144 bunkers and six 122mm guns destroyed. After the initial period of bad weather, the Marines picked up the tempo of the operation as it entered its fourth week. Driving toward the Laotian border, the Leathernecks pushed out from fire support bases in an almost classical regiment-in-the-attack envelopment - a move reminiscent of tactics used during the Korean War. Based on the enemy's refusal to leave the area under the cover of bad weather, Marine intelligence indicated that the NVA were prepared for helicopter assaults with extensive anti-aircraft gun defenses. Therefore, the Marines struck to the ridgelines, traversing some of the most rugged jungle terrain in Vietnam on foot. The ground assault on the enemy's perimeter paid off and the NVA's extensive air defense system in the area was rendered useless. The NVA fought hard for its previously untouched sanctuary and made several desperate attempts to halt the Marines' drive. On two occasions the enemy initiated unsuccessful attacks on Marine fire support bases. These cost the enemy’s 67 dead, On February 23, an estimated NVA battalion entrenched in an extensive bunker complex sought to stop the Marine push. Two companies of Marines and a combination of Marine artillery and Marine air strikes dislodged the determined enemy force and when the fighting ended, the Marines counted 105 NVA dead. In an analysis of the Marines' success during Operation Dewey Canyon, Lieutenant General Richard G. Stillwell, U.S. Army, Commanding General, XXIV Corps, said: " Dewey Canyon deserves some space in American Military History by sole reason of audacity, guts and magnificent inter service team play. There was a calculated gamble on weather and for the most part it was won. If the weather had held throughout, the greater momentum would have made surprise complete, with proportionately greater results. But the troops pressed on through marginal weather, enduring real privation. And somehow, minimum essential supply and evacuation went on. "I cannot applaud too highly the airmen of the 1st Marine Aircraft Wing in a variety of dangerous roles, the 101st Airborne Division Hook Company dedicated to the operation, the fighter pilots - Marine and Air Force - who managed to penetrate the overcast and deliver devastating close air support and effective interdicting blows. "Above all, though," the general concluded, "A Marine regiment of extraordinary cohesion, skill in mountain warfare and plain heart made Dewey Canyon a resounding success. As an independent regimental operation projected 50 km - as the crow flies - from the nearest base and sustained in heavy combat seven weeks, it may be unparalleled. Without question, the 9th Marines' performance represents the very essence of professionalism." Lieutenant General Robert E. Cushman Jr., Commanding General, III Marine Amphibious Force, praised the performance of the men involved in the operation by enumerating their accomplishments and saying they delivered a heavy blow to the enemy's capability in a critical area. General Cushman said, "These accomplishments in the remote and densely forested mountain terrain and in severely limiting weather conditions heap credit on every Marine, Navy man and Army trooper involved and underscores the high level of professionalism of participating units “To all hands, a hearty well done." - The above wrap-up on the operation was released at Da Nang at 2000 hours, 20 March 1969.