Losing Vietnam (43 page)

The enemy had concentrated its fire at three areas. The best way to eliminate the enemy threat, particularly the ground fire and mine threat at Peam Reang, was to land troops on the ground and take over the choke point. Until troops were made available to control the choke
points, enemy firepower remained a major threat to ships, though not to tugs and barges. However, mines were a major threat to tugs and barges. The navy did not intend to sweep the Peam Reang area until FANK controlled the banks. The army was to send the 69th Brigade to Neak Luong to replace the 4th Brigade, which would clear the area near Peam Reang. However, landing troops would take some time.

Photo 8. Barricades on the Mekong with Sunken Tugs. (Source: Headquarters USSAG, Nakhon Phanom, Thailand, produced by 432nd Reconnaissance Technical Squadron, U.S. Air Force.)

Throughout these periods, the enemy continued to refine its interdiction tactics and in time became much more coordinated. It formed special Mekong River units. One of these operated in Kandal
Province south of Prek Doch village. This consisted of heavy weapons Battalion 260 and support Battalions 18 and 265.
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Another battalion established ambush points further north, digging trenches 250 meters apart, each of which was for seven men and had emplacements for four 75 mm recoilless rifles and two 82 mm mortars. When the convoys traveled at night, the communists would set up a series of kerosene lamps which were shielded so that the light was visible only to their dug-in firing positions along the opposite riverbanks. As a darkened convoy approached, a downstream observer would alert the positions by firing a shot. The gunners would then aim their weapons at the kerosene lamps, and when the advancing ships blocked the light, the gunners opened fire. A sizeable percentage of enemy forces, more than eight thousand troops, had as their mission the interdiction of convoys on both the upper and lower Mekong.

On 7 February, it was important to go all-out to prepare for TP-115. Each of the Khmer services had its problem to solve. The convoy could be successful only if the Khmer, Vietnamese, and U.S. organizations worked together, and unless TP-115 was successful it did not appear possible to run subsequent convoys in the near future. Everything was riding on this convoy.

The army had established a sound plan to land troops on the banks. The navy was actively preparing for minesweeping operations, and the air force stood ready to fully support the effort. SEAPAC had made excellent progress in designing and fabricating a minesweep that would clear the river. Plans called for five tugs: one to push the minesweep and double tugs for the two ammo barges. Whether they would cross the border depended on many factors: troops on the ground, adequate river sweeps, sufficient naval escort, a deputy commander on the lead tug, machine gun crews and grenadiers aboard tugs, English- and French-speaking radio operators, and the convoy sailing on schedule. These factors would require formidable operations between then and the convoy sailing time, set as 18 February at the earliest and 20 February at the latest. It remained to be seen whether the Cambodians were up to the task.

With the 5 February failure of TP-114 to resupply Phnom Penh, the stockage situation was beginning to pinch a little.
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There were thirty-six days' rice supply at the current consumption rate of 545
metric tons per day and about forty-five days' petroleum supply. The civilian petroleum allocation was reduced from 258 to 121 cubic meters per day—a big cut. Certain line items of ammo were below the fifteen days of supply, including 5.56 mm rifle, 60 and 81 mm mortar, and 105 and 155 mm howitzer rounds. There were only six days of napalm and cluster bomb air force munitions. To alleviate the situation the JCS directed the U.S. Air Force to augment the existing Bird Air contract to supply Phnom Penh to provide twenty sorties of airland missions per day (an increase of thirteen sorties per day), which would hopefully take care of the supply situation until the Mekong convoys were resumed.

That week, the ammo consumption for Phnom Penh alone was 640 short tons per day. The army planned to make every possible effort to reduce the rate to 400 short tons per day for the rest of February and then to 300 short tons per day thereafter. This still exceeded the 1 January 1975 strictly established authorized supply rate of 290 short tons per day, dangerously depleting the existing funding authority. Even if the Mekong convoys resumed, there would be a very severe ammo problem. The current Mekong closing and the projected ammo rationing deleteriously affected Cambodia's morale.

Reviewing Mekong security as we looked ahead, the navy's suppressive fires had not been effective, except for the monitors, which had 105 mm guns. The smaller boat platforms were, unfortunately, always below bank level, preventing an effective line of fire. The artillery fire support also was not effective, in that case because of poor leadership. Whenever the air force provided close air support, its five-hundred-pound bombs did silence the enemy trenches—but they were often unavailable during the day and obviously ineffective at night. The only really effective solution was to place troops on the ground at choke points. Recognizing this, on 6 February the joint staff made the Mekong Special Zone an army command (vice navy) and placed Brig. Gen. Noup Paramoun, the MR-6 governor and commander, in command.
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He would have a navy deputy and an air force field-grade officer as advisers, and he would eventually have a ground force of two and a half brigades, in addition to the forces defending Neak Luong. With these troops, he was to reoccupy lost artillery positions and emplace more artillery so that mutually supporting gun positions would cover the lower Mekong from the border to Phnom Penh.

Subsequently, neither the army nor the navy could get organized with respect to Mekong security, and on 26 February 1975 we sent a very strong message to all concerned:

Now that the Mekong River line of communication, the lifeblood of Phnom Penh and thus Cambodia, was closed, alarm bells should
have sounded at the joint staff when the battle-weary marines failed to occupy critical positions on the lower Mekong. True, they discussed a plan for the lower Mekong and they changed the command structure, but they failed to provide the one essential ingredient—more combat battalions. The chief of staff, Lieutenant General Fernandez, had stated on several occasions that he would never allow a provincial capital to be taken. However, by the end of January the preponderance of all enemy main force units had been relocated to attack Phnom Penh and the lower Mekong. It is true that in that month some troop units from outlying areas were relocated to the capital region to counter communist attacks; those troops aside, however, the bulk of the territorial battalions remained in outlying areas to protect the provincial enclaves. The cautious attitudes of the joint staff allowed the intermittent enemy local force attacks to fix those territorial units in place. The failure to substantially reinforce the lower Mekong with additional units from the outlying regions ultimately resulted in the downfall of Cambodia.
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Coincidentally, just the opposite occurred in South Vietnam, where President Thieu's precipitous directives to withdraw forces from MR-1 and MR-2 to protect Saigon and the delta had catastrophic results, leading to the collapse of the South Vietnamese government.

The Khmer communists' strategic plan was to completely isolate Phnom Penh by cutting all avenues of approach. In 1975 they had driven close to Pochentong and were seriously interdicting the airfield. Notwithstanding the constant artillery and rocket attacks, the JCS had approved increased airlifts when, on 5 February, TP-114 was turned back. Now, at the end of February, when it was clear that the Mekong was definitely closed and a further increase in airlift was essential, we were concerned that additional funding would not be approved and flights into Pochentong would even be curtailed because of the increased shelling of the airfield. The airfield's interdiction was becoming more effective. The communists had obviously located artillery so they could fire directly along the narrow airfield's axis. On 23 January, when my airplane was taking off, the enemy walked six rounds smack down the center of the runway. The first four detonated behind the aircraft, each
closer than the last. And when the aircraft was over a hundred feet off the ground, the last two exploded under it, rocking the plane.
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It was really a race against time, and the enemy's timing was off by seconds.

In January and February, 745 rounds hit Pochentong Airfield and fragments severely wounded several cargo handlers. Nevertheless, higher headquarters unhesitatingly approved additional sorties to fully support Cambodia. Our military did not back off. Subsequently, our tactical analysis branch prepared a paper titled “Risk Associated with Pochentong Airlanded Operations,” taking into consideration the incoming rockets' ground pattern. They concluded that there was a relatively high probability of at least one aircraft being hit or damaged if operations lasted more than thirty days. The matter was receiving the utmost attention at Headquarters USSAG; we constantly monitored firings, landings, and offloadings on an event basis.

Enemy attacks on Pochentong continued to increase, and in March 211 rounds of 105 mm artillery and 872 rounds of 107 mm rockets hit. During the dry season, more than 2,400 rounds were fired at the airfield.
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Fortuitously, we lost no aircraft, although shrapnel damaged eight. The United States had no casualties either; however, the Cambodians supporting the operation suffered more than fifty, including eight killed. MEDTC reported on 11 April that shrapnel hit a DC-3 carrying a cargo of diesel fuel during takeoff and five crew members were killed in an attempt to land the aircraft.

Besides moving operations from one location to another and temporarily suspending operations during periods of intense attacks, the U.S. Air Force supervisors constantly strived to reduce offload times and total ground times. Obviously, the shorter the ground time, the less the risk. The average C-130 ammunition block-in to block-out offload time was 5.9 minutes, and the total ground time was 10.6 minutes. For other cargo loads the ground times averaged 29 minutes.
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Now that the Mekong River was indefinitely closed, the airland/airdrop delivery methods assumed the greatest importance. In mid-January, our staff had commenced planning for that possible contingency. From March to December 1974, once the Mekong convoys really started moving, airlanded cargo averaged only 230 short tons per month, less than the equivalent of one sortie per day. However, because of the enclave situation, the need for airdrops persisted all year. The average
total commodity deliveries per month, exclusive of road deliveries, was 68,900 short tons. Such quantities could no longer be feasibly delivered solely by air; therefore, the American embassy, Phnom Penh, USAID, and MEDTC jointly determined an austere posture of 41,500 short tons. After they cut the requirements by 42 percent, there was still a need for ninety sorties per day. Whether that number could ever be accommodated remained to be seen; to sustain this level of airlift there would have to be a capability to load, transport, and unload about 1,350 short tons per day. Fortunately, there was an additional staging area at the southwest corner of the airfield at Pochentong, which would enable satisfactory loading and unloading. Thus, capacity would be limited only by the availability of ground equipment, U.S. personnel for surveillance, and air and ground congestion (not considering enemy interdiction). With proper equipment, we could surge to seventy-two sorties per day at Pochentong, which would require four to six U.S. ground handlers to oversee offloads and two U.S. Air Force air traffic controllers. To stay under the two hundred personnel ceiling mandated by law, U.S. personnel would have to arrive by first sortie in the morning and leave on the last sortie of the day.