Case of the Mysterious Lob Bomb | HistoryNet MENU

Case of the Mysterious Lob Bomb

By Stanley F. Cherrie
11/13/2017 • Vietnam Magazine

Protecting the drawdown of U.S. troops in 1971, a cavalry squadron was hit with a puzzling—and terrifying—enemy tactic.

At long last, the stewardess announced that we would be arriving at Cam Ranh Bay shortly. It was early March 1971 and for the first timers on board there was a sense of electric excitement. For myself, I was thinking a lot about my first tour flying UH-1C guns in 1967-68 and wondering what type ship and where I would fly. I was aware of the shortages relating to the drawdown of U.S. troops, so I didn’t know what to expect.

Soon after the 707 touched down, we were bused to a replacement depot where we were given bunk space, drew our gear and then were whisked off to a mess hall for a rather good, late supper. The next morning after chow, we received our assignments. I drew the 23rd Infantry Division, the Americal Division. “Oh my God,” was my first thought. The My Lai massacre stench was still in the air. I was more than displeased with the assignment and had no idea what type aviation units were in the division. The next morning, I caught an Army Caribou transport that flew several of us Americal newbies to Chu Lai, where we were to begin the Americal Combat Preparation School, a two-week course that covered the waterfront on how to stay alive in Vietnam.

One morning early in the second week, I was pulled out of class and told to contact the 2nd Brigade commander’s office. I did and was invited to the commander’s mess for dinner. I was driven to the beachside mess, a beautiful “China Beach”–like setting. I mixed well with the brigade staff officers, and the meal and service was almost too good to believe: Philippine waiters, china, cloth napkins, wine.

After dinner, the brigade commander invited me into his office and began talking about “his” 2nd Brigade Cavalry troop that had recently performed very well in the March 1971 Lam Son 719 incursion into Laos. He had noticed from my records that even though I was an aviator, I had commanded an armored cavalry troop in Germany. He then flat out asked me if I would be willing to take H Troop for six months.

All night I weighed the pros and cons of ground command versus assignment to an aviation unit. The thought of commanding cavalry troopers again, for even six months, put the decision over the top as a “yes!” Early the next morning, I told the brigade commander I would be honored to accept the position.

Little did I know how that decision would lead me into one of the most challenging and terrifying experiences as a commander that I would face in Vietnam, testing my ability to react to and counter a mystifying and devastating enemy tactic.

After completing the Combat Preparation Course, I was taken to the H Troop, 17th Cavalry, cantonment area of tarpapered Quonset huts lined up in neat rows separated by company streets. I went to my hooch, which appeared to be more like a prison cell with double bolts on the door and so much chain link fence over the windows that air could hardly get in. I was told the wire was there to protect a previous commander—from fragging! I muttered to myself, “What the hell have I gotten myself into now?”

Shortly, 1st Sgt. John Stephens approached me for a heart-to-heart talk. We sat in his office and talked for hours about what we needed to do in order to bring H Troop to U.S. Cavalry standards. In fact, the troop was reflecting the problems and upheaval shaping the Army and American society in general.

Several weeks of field duty security missions, however, had a dramatic effect on raising troop morale and building cohesiveness, and gradually we could sense a “wellness” developing within the troop. In early April, we went back to Chu Lai for maintenance and a brief rest, and learned that we were to become part of a “provisional” cavalry squadron, organized to provide security operations under a new provisional squadron commander. A giant of a man, Lt. Col. Frederick Wilmouth looked like a big green grizzly bear, with huge hands and a genuine smile. I also met Captain Jim Wilson, a proficient, savvy, combat leader.

We all sat down and had a “Da Nang drawdown” sketched out for us. In order for this concept to work—providing security in a great arc from the north and around the west of Da Nang to the south— close coordination was paramount. With little squadron coordinating staff available, Wilson and I knew that troop-to-troop cross talk was essential.

Our mission would take us to the edge of the plain west of Da Nang and on west to the mountains. We were to screen the area for infiltrations of company-sized Viet Cong (VC) or North Vietnamese Army (NVA) units that could attack the bases in the Da Nang vicinity to disrupt the time-phased withdrawal of U.S. troops that was underway.

We were headed generally toward a town named Phu Lac where we would screen and patrol the area, as the avenue from the mountains to Da Nang was thought to be a viable attack route for VC and NVA units.

Soon we fell into a daily routine of searching for caches of enemy weapons, bunker complexes, food and weapons. For the most part, we were coming up dry with next to nothing of value to show for almost a month in the field.

One fact that was clear was the lack of military-aged Vietnamese males we saw during our daylight operations. Plenty of women, elderly men and young children, but no 17- to 25-year-old males at all.

Our standard method of operations was to leave one platoon from the previous night’s ambush mission as a troop security force to rest while maintaining a 50-percent alert. Near day’s end, this platoon would join the troop and prepare to swap positions with that night’s ambush platoon mission and take its position within the troop’s night defensive position (NDP), which had been reconned earlier. No matter how many times a commander may have set up an NDP, it was always a high-stakes event, ensuring that everything that needs to be done has been done, and done correctly.

Near the end of the second week of April, I was told by our squadron headquarters to rendezvous with a company of Regional Forces Popular Forces (RFPF), commonly called “Ruff Puffs,” that would be attached to us for a couple of weeks. They ranked somewhere between Vietnamese army soldiers and Montagnards— more organized than the “Yards” but not nearly the caliber of fighters they were.

We were met by a rag-tag unit of about 100 men scattered about in a dusty rice paddy basin, with absolutely no security in place, backpacks stuffed with live ducks and chickens, and old weapons that I wasn’t sure would even fire. An American captain who was advising the band approached me. We agreed that the RFPFs would ride on our tracks until we came to an area that needed to be reconned. They would then dismount and provide the additional boots on the ground that we needed to function more efficiently.

Along with the “nicety” of having dismounted infantry, however, came a steep bill, which their adviser began to detail. The RFPFs weren’t exactly early risers and they needed to be situated near a water source each evening so they could cook their rice and vegetables. They weren’t too good in the security game, having a reputation of sleeping while on sentry posts. The list the captain was running through seemed to go on forever, so I finally interrupted him and said, “Hey Pal, I’ve been doing just fine with the troop without you folks so far, so with the list of musts you just gave me I’m not sure I can live with it.” I told him we would attempt to meet his troops needs, but if we couldn’t, then they would just have to suck it up.

The RFPF unit requirements placed additional pressure on our scouts to find NDPs that met our security and their administrative requirements, leaving us far fewer suitable NDP candidates. I would soon learn the perils of this situation.

As we pulled into the area selected as our NDP on the very first night after our link up, I went ballistic, ranting about the position’s weak defensibility and lack of decent fields of fire. Meanwhile, the Puffs parked their rucks, started their fires and began bathing and hauling water for cooking—out of the same damn river. I decided I would have to develop a mechanism to keep me from getting boxed into accepting an NDP like this again. Unfortunately, I failed to recognize the signs that this place had been used as a night defensive position before. Used fire pits, three-legged branch cooking pot holders and several shallow fighting positions were already there.

We had shifted to a new paradigm, but I was too young and inexperienced to realize it. As a direct result, what would unfold in the next few days and weeks was a period of fear bordering on terror. When I think of it four decades later, it still gives me chills.

The following day was uneventful with no enemy contact and little of anything found. Again around 1700 we went into the standard night laager routine, position occupation, laying in artillery, emplacing mortars, setting claymore mines and erecting RPG screens—chain-link fence to defeat the rocket-propelled grenade’s shaped charges.

The NDP perimeter was about 100 meters in diameter, with the command group consisting of my M113 ACAV track, three 81mm mortar tracks, the medic, a supply track and another couple of administrative wheeled vehicles. We had integrated the dismounted RFPF forces into our perimeter, with their fighting positions located between every third U.S. track. We had a total of 30 tracked vehicles. Our communications were good.

That evening, after touring the perimeter for a third time and finding all in order, I decided to try and get some sleep in my ACAV in a hammock strung from behind the driver’s hatch to the right rear of the track. I laid in the hammock, feet on the floor, and held a radio hand microphone for the troop command net in one hand and the squadron command in the other.

It was stone quiet at 2400 hours and, just as I was giving a “negative SITREP” to squadron headquarters, several small explosions went off in rapid succession inside our perimeter. I immediately grabbed my steel pot and portable radio. As I exited the vehicle’s back door, I saw a scene of utter chaos, eerily illuminated by our 81mm mortar flares. The RFPFs were scurrying all over the place as our guys manned their weapons on their tracks and in their individual fighting positions. Maintaining combat discipline, no one was firing his machine gun. My immediate assessment was that we were under a 60mm mortar attack, probably designed to let us know that the VC were alive and well—and that they damn sure knew where we were.

Only seconds after my feet hit the ground, a tremendous explosion from across the perimeter ripped through the air, literally blowing me off my feet, tearing the radio from my grip and sending my unbuckled helmet flying. As I got up on my hands and knees and gazed across the perimeter, I saw one of our tracks engulfed in flames. The ramp was down and there appeared to be some movement inside.

I ran to the track, reaching it as one of my scout sergeants was pulling an unconscious trooper from the flaming vehicle. We dragged the smoldering trooper about 25 meters from the track. Another crew member had been blown out the open back and had a wicked gash on his forehead. Immediately the ACAVs on the left and right had “buttoned up” and repositioned to maintain perimeter integrity and minimize the danger from ammunition that would soon cook off.

After reporting to squadron, I called for a muster to account for personnel, then called for a medevac for the two wounded U.S. troopers and a number of RFPFs. We had one man unaccounted for, and seven RFPFs who had been in fighting positions near the burning track were missing and assumed to be dead.

When the dustoff came in, there was a wild clamor by terrified Ruff Puffs who appeared ready to storm the copter. I had to threaten the Vietnamese RFPF leader before he gained control of his men. I told the aircraft commander that this would be one of several lifts, as I was sure come daylight we would find more casualties.

All the while I was racking my brain trying to figure what could have caused this carnage. It wasn’t an artillery shell, for the explosion certainly was too big for that.

Shortly after the dustoff departed, one of my M-551 Sheridan Light Tank commanders was found dead on the back deck of his track, apparently from a shrapnel wound to his skull. He was sleeping in his bag on his tank’s back deck. When the initial rounds went off, he probably sat up and was struck by a piece of shrapnel when the big blast went off.

It was a long, jittery night. Everyone was on 100-percent alert, having no idea what had just happened and fearing that something like it would happen again.

The burning track smoldered, and as the sun’s first rays lit the perimeter you could see its .50-cal machine gun drooping from the intense heat, still locked into its mount atop a charred aluminum box. I ordered the men to fill five-gallon cans with nearby river water and cautiously pour it over the unexploded ammunition on the track’s floor. Once we were certain that the hulk and unexploded ammunition had cooled sufficiently, we gingerly approached. I was amazed to see a crater on the right side of the track, about 10 feet deep and looking like what I’d seen during my first tour when I had done Arc Light raid bomb damage assessments. The center of the crater was directly in the center of several RFPF fighting clusters, where the seven missing RFPFs had been.

I called squadron and requested that they send an explosive ordnance disposal (EOD) expert out to see if we could ascertain just what hit us. I believed it could have been an errant bomb that had inadvertently “pickled off” from a plane returning from an attack mission. I cancelled combat operations for the day and figured I had to get the soldiers’ minds off what had just happened.

Meeting with squad leaders and above, I told them that I was as perplexed as they were, but that the good part, if there was any good part in this situation, was that we had sustained minimum losses and had not been subjected to a second ground attack. I wanted the men to get some of the rest that they had missed the night before and stand by to resume combat operations in the morning. They gave me a salute and went about their work.

The EOD team choppered in, and in less than an hour they brought me a metal plate that looked like a piece of stainless steel. They said it was the base of a 250-pound U.S. bomb and confirmed that the crater could have been made by a bomb that size, detonating at ground level. They continued to search in and around the crater and found several metal shards that convinced them that it was indeed a 250-pound bomb that had done this damage.

I had ruled out a buried command-detonated 250-pound bomb, as the EOD team said that whatever made the explosion had detonated on the surface. Otherwise, the crater would have been much deeper. Still thinking the bomb had fallen off the wing of an aircraft, I requested squadron check Air Force and Navy flights during the 2400-hour time period.

Regardless of what had done the evil deed, or how it had been delivered, the troop was reeling from the shock. But we had to put it behind us and get on with our mission. The next morning, we resumed our tactical screening operations as usual, without incident.

After about a week, we were slipping the bonds of fear that had gripped us in the wake of the mysterious bomb incident. Then one night, as it was getting dark and we were safely in our night defensive position, we started taking incoming 60mm mortars again. We took about 10 rounds in quick succession and then there was nothing but an ominous silence. I called the platoons and found that we had had no casualties and no damage resulting from the mortar attack.

Five minutes later, I got a call from one of my Sheridan commanders, Sergeant Moye, telling me that he believed he had found a “torpedo” laying next to his track. We were 40 kilometers inland for Christ’s sake! A torpedo? I grabbed my helmet, radio and flashlight and made my way to the 2nd Platoon’s arc of the NDP. When I reached Moye’s Sheridan, he was standing on the back deck, pointing to the ground on the right side of his track.

Moving around to the side of the track, I turned on the red filtered flashlight and there it was: a finless 250-pound U.S. bomb laying just 10 feet from the track. The bomb’s nose fuze looked as if it had been disgorged from the bomb itself. A pair of wires trailed from the fuze and were still attached to the bomb.

I wasn’t exactly sure what I was seeing, but was smart enough to know that we had a very dangerous situation on our hands and that we had to get the hell away from this highly explosive bit of ordnance, fast.

I ordered the tracks on that arc of the perimeter to move and double up with left and right platoons. I called squadron and requested EOD support again, and then called a command huddle on the far side of the perimeter.

Next I ordered a quartering party to immediately move to one of the alternate NDP sites, then return and guide us there as quickly as possible. Everyone was to load up and prepare to move, but leave the RPG screens in place. We would also leave a team of two scout tracks about 500 meters away from the bomb to watch the NDP and the bomb until we could get the EOD team in. The troop then quickly moved about three kilometers for the rest of the night.

Throughout the night, I kept trying to figure out how these massive bombs came to be placed so near to my troops. In the morning, one of my platoon leaders came to me to report that our Kit Carson scout—a repatriated VC—had called them “lob bombs.” I had the scout brought to my track along with our interpreter. He took a pencil and hurriedly sketched out just how the Viet Cong would take unexploded U.S. bombs, cut them in half to extract the high explosives and turn them into booby traps, mortar rounds or hand grenades. Another use, he explained, was to use them as “lob bombs.”

The VC were smart, patient and knew how their enemy fought. They knew what we looked for in a night defensive position and, because our Ruff Puffs’ needs made us so predictable, they knew how the perimeter would look even before it took shape on the ground. As such, he said, they would locate formerly used NDP sites, then scratch out a trench deep enough to encase the bomb just two or three inches under the surface. Selecting the exact position was critical, he explained, for they ideally wanted the bomb to be outside the perimeter to keep it from being run over and exploded or compromised as the NDP was being set up.

The Viet Cong would place the bomb longwise in the trench on a radial from the forecasted center of the NDP. Then, under the bomb, about a third of the way up from the tail end, they placed a small, low-velocity tamping charge that was just strong enough to propel the bomb, end over end, into the perimeter. The bomb itself was fuzed with two wires that would initiate detonation upon contact with the ground. It was this detonating mechanism that I had seen on the bomb that failed to explode when the fuze dislodged on ground contact. The Kit Carson scout went on to explain how the detonation of the tamping charge was usually preceded by a small perimeter probe or an indirect-fire harassing attack, intended to get the troops running around for cover just prior to the ground level detonation of the bomb.

At that point, I realized that these little fighters were more sophisticated than I had given them credit for being.

As we awaited the EOD team’s detonation of Sergeant Moye’s “torpedo,” I was a little afraid to communicate all that I had learned to all of the men. I felt like my NCOs at platoon level could handle it, but I kept it from rank and file to avoid panic. When the explosion rocked us at even three kilometers away, I shuddered with fear contemplating what might have been.

Now, I had to find a way to eliminate or at least ameliorate the enemy’s ability to snipe at us with 250-pound bombs. Obviously, they were watching our every move, could predict where we would be as nightfall closed in and therefore could easily plan on what damage they could inflict on us that night. It occurred to me that if the enemy needed time to select a location and “wire in” his command detonation system, he had to start his preparation when we gave signs of preparing to laager. I figured if we attempted to disguise where we would spend the night as long as possible, that would lessen the time the enemy had to wire in those command-detonated tamping charges to adequately prepare their destructive weapon.

So, our NDP scouting parties were instructed to select a primary NDP and two alternate sites and show no partiality to any of the three. We also changed our heretofore-standard U.S. method of NDP selection and preparation. In late afternoon, at 1600 or so, we’d begin to make a big deal of staking out our perimeter. This would be NDP No. 1, where we would occupy and do everything that was needed to protect ourselves. Then I would send the quartering party to NDP No. 2 as we tore down NDP No. 1 and prepared to move.

Moving an armored cavalry troop in the dark was like moving Barnum and Bailey’s circus—not the quietest operation around—and I was worried that we would be RPG ambushed as we were preparing to move. But, since I had no median timings as to how long it took for the VC to adequately prepare to command-detonate the launching charges of a lob bomb, I was operating on pure gut feel.

Over the next few weeks, this became our standing operating procedure, and it appeared to work. Either the enemy didn’t have as many cached bombs as we thought he might have, or we were ahead of him, however slightly, in his planning and execution cycle. It was not without negative consequences for the troops, however, who were being seriously overworked and ragged as a result of little sleep.

Likewise, as the troop commander, I had never been in such an extended period of constant stress and worry in my entire career, as every decision had potentially disastrous consequences. I still believe I made the right decision to not tell the troopers what the real deal was in this case.

After several harrowing weeks, we were ordered back to Da Nang and then, after a brief rest, back to our base camp at Chu Lai. We were more than ready to get back home, catch our breath and relax just a bit.

In a world full of acronyms, few instill as much dread and embody evil as thoroughly as IED, shorthand for the improvised explosive device, a weapon made far too familiar to Americans in the first decade of the 21st century. Although the British coined the term in the early 1970s to describe Irish Republican Army terrorist tools, IEDs were significant weapons used by the Viet Cong and North Vietnamese against U.S. troops during the Vietnam War. In Vietnam, however, most were smaller, mine-like booby trap devices in comparison to the “lob bombs” my troop encountered in 1971 and the often massive IEDs employed in Iraq and Afghanistan that have claimed nearly 3,000 U.S. troops to date.

 

Brigadier General Stanley F. Cherrie served two tours in Vietnam, was the operations officer of VII Corp in Operation Desert Storm, and from 1993 was assistant division commander for maneuver of the 1st Armored Division in Germany and Bosnia. He has been awarded the Distinguished Service Medal, Silver Star, Distinguished Flying Cross, Legion of Merit, Air Medal with “V” Device and the Purple Heart.

Originally published in the December 2011 issue of Vietnam Magazine. To subscribe, click here.  

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