Written by Matthew Copes
The last battle of the Vietnam War occured in mid-May of 1975, just two weeks after the fall – or liberation, depending on which side you were on – of Saigon.
These days however, the incident has largely been forgotten, perhaps because it didn’t actually take place in Vietnam, nor did American Marines square off against NVA or Vietcong forces, but against belligerents from a neighboring country who’d been at odds with Vietnam for millenia.
Though nobody’s sure who said it first or when, an ancient proverb states that “the enemy of my enemy is my friend.”
If the aforementioned adage was a universal truth, an enemy of the new Sociaist Republic of Vietnam should’ve been a friend of the United States, but in this instance that wasn’t the case.
During the incident 50 American servicemen were wounded, nearly 40 were killed in action, and three more were captured, beaten to death and buried in shallow graves.
Sadly, had the United States recognized this country’s claim to a 12-mile territorial buffer around its coastline the whole affair may have been avoided altogether.
Now, the Mayaguez incident.
Nearly four decades before the Khmer Rouge gained control of Cambodia, French colonial administrators concocted the Brevie Line to register which islands in the Gulf of Thailand belonged to Cambodia, and which belonged to Vietnam.
Both countries had little choice but to accept their colonial master’s arbitrary ruling, but with much of Southeast Asia in chaos in the spring of 1975, the Khmer Rouge demanded that all Vietnamese forces leave its territory immediately.
This went for the historically disputed land between the two country’s borders along which the Ho Chi Minh Trail ran, and in particular, the islands of Phu Quoc and Koh Tang in the south.
But at the same time as it was being ordered out, Vietnam was conspiring to take additional territory and islands from its smaller and less powerful neighbor.
As a result, during the summer, fall and winter of 1975, various disputed coastal islands changed hands numerous times, often after brutal engagements that ended in unspeakable atrocities.
In one instance on the 10th of May, Khmer Rouge forces captured the Thổ Chu Islands, after which they executed the nearly 500 Vietnamese civilians who’d resided there.
Not surprisingly, the Vietnamese responded with brutal reprisals.
Though small and ill-equipped, the Khmer Navy actively patrolled its coastal waters to deter future incursions, and to ensure that merchant ships didn’t supply its internal and external adversaries with arms.
In addition, the Navy regularly boarded and inspected Thai fishing boats, and had run-ins with ships from Korea, Sweden and Panama to name just a few.
But though the Khmer Rouge was especially suspicious of all outsiders, they were particularly wary of the Americans – specifically the CIA, which had installed, bankrolled and manipulated the hopelessly corrupt Lon Nol regime that’d ruled the country before the civil war.
Taking of the SS Mayaguez
On May 12, the US container ship SS Mayaguez was passing the coastline between Vietnam and Cambodia en route to Thailand.
On board were nearly 300 containers, more than 70 of which contained undisclosed freight that had been picked up from the embassy in Saigon before the evacuation.
At just after 2:00 PM a Khmer Navy patrol boat was spotted approaching Mayaguez at a high rate of speed, and when it was within a few hundred yards the heavy machine gun on its bow erupted, spewing a hail of lead across the path of the larger ship.
Initially, Captain Charles Miller ordered the engine room to reduce speed, but when the assailants produced and fired an RPG at the waterline dangerously close to the Mayaguez’ hull, he brought the ship to a full stop.
Certain that the situation was about to go from bad to worse, the radio operator quickly broadcast a Mayday that was picked up by an Australian vessel nearby, and moments later more than a dozen armed Khmer Rouge soldiers were in the pilot house.
Since the Cambodians didn’t speak English and the Americans didn’t speak Khmer, communication was nearly impossible, and the atmosphere became increasingly tense.
Ultimately, Commander Sa Mean pointed at the ship’s map, indicating that he wanted the captain to take Mayaguez to a point farther east of the island.
At gunpoint, Captain Miller and the 38 crewmen did as they’d been ordered, and by 4:00 PM the ship was anchored and another 20 Khmer Rouge soldiers were on board.
Then a few hours later after multiple communications with his superiors, Sa Mean once again pointed to the map, this time making it clear that he wanted the ship taken to the naval base at Ream.
Tapping on the radar screen and shaking his head from side to side, Captain Miller convinced him that the vital navigation tool wasn’t working, and that if they proceeded the ship might strike submerged rocks and sink.
Considering the situation, Sa Mean again radioed his superiors and was instructed to sit tight until they decided what to do.
Mayaguez’ distress call was forwarded from the Australian vessel to the US Embassy in Jakarta, and from there to President Gerald Ford, who hastily convened a meeting of the National Security Council.
Keen to avoid another situation like the one involving the USS Pueblo in 1968, the President and his advisors made wrapping up the affair quickly and quietly a priority.
Considering the rumors of atrocities leaking out of Cambodia, and because the US government didn’t have any official diplomatic relations with the Khmer Rouge, keeping the crew away from the mainland was of the utmost importance.
After the meeting in Washington, US reconnaissance P-3 Orions based in Thailand were dispatched to locate the ship, while President Ford instructed Secretary of State Henry Kissinger to reach out to his contacts in China to see if they could convince the Khmer Rouge to release the ship and crew.
But though the P-3s located Mayaguez quickly, they were fired on by antiaircraft guns and had to abort their missions.
With the situation deteriorating, Marines in Japan and the Philippines were put on alert, and the aircraft carrier USS Coral Sea, two destroyers and various support ships were ordered to the area.
Now convinced that firing on the P-3s would lead to heavy retaliatory strikes, Sa Mean ordered Captain Miller to reposition the ship once again.
However, it didn’t take long for the Americans to find it, and just a few hours after dropping anchor the sky over the Gulf of Thailand was swarming with F-111s and F-4 Phantoms.
Using their 20 mm rotary cannons, the Phantoms strafed the water immediately ahead of the ship’s bow, indicating that further movement would be met with lethal force.
The American planes departed as the sun set, and intent on making the most of the reprieve, Sa Mean ordered his men to load the merchant mariners into fishing boats and take them to the island of Koh Tang about 30 miles (50 km) off the coast.
The following day, Marines began arriving at U-Tapao Airport near Pattaya, Thailand in preparation for a hastily planned, multi-pronged assault that would commence the following morning.
If all went according to plan, dozens of Marines would repel from CH-53 helicopters onto the top of the shipping containers stacked on the deck of the Mayaguez.
While en route however, one of the CH-53s crashed killing the 5-man crew and 18 Marines on board, and as a result the entire mission was canceled.
Again the Americans were loaded onto small boats destined for the port at Kampong Som to the east, when F-111s, F-4s and A-7s appeared and began firing on them.
None of the boats were hit, and when at least one pilot visually confirmed that there were caucasians on board the attacks were immediately called off.
But though a friendly fire incident had been averted, the aircraft lost track of the boats in the port of Kampong Som.
Fearing that holding the American prisoners there would provoke a far worse air attack that could potentially decimate Cambodia’s already weak Navy, the Khmer Rouge commander ordered that the crewmen be taken to Koh Rong Samloem about 20 miles (32 km) to the north.
However, since this was done at night it was unknown to the Americans.
As far as they knew, some of the crew were still on Kho Tang, some were in Kampong Som, and yet others may have still been on Mayaguez.
Just two days after Mayaguez was taken, Marine units were ordered to assault Koh Tang from two sides.
What they didn’t know however, was that there weren’t any American merchantmen there, and that was the least of their problems.
Initial intelligence had determined that the island was occupied by 200 Khmer Rouge soldiers who were dug in and equipped with heavy machine guns, RPGS, large caliber recoilless rifles and mortars.
But sadly, this information was never relayed to mission planners who’d been led to believe that the force guarding the island was one-tenth its actual size.
Pre-mission reconnaissance flights revealed that much of Koh Tang was covered in thick jungle, and that there were only two suitable landing zones on beaches on the island’s east and west sides.
All told, hundreds of Marines would be dropped onto the two beaches, after which if all went according to plan, they’d storm toward the center of the island to rescue the American crew – as in the crew that wasn’t actually there.
The Navy and Marines briefly considered airstrikes to soften up the island’s defenders, but instead, aircraft would attack multiple targets on the mainland as diversions,and to prevent reinforcements from making their way to Koh Tang.
Now thanks to inaccurate intelligence, poor communication and inadequate planning, the stage was set for the needless invasion of a strategically useless island that would ultimately result in an epic military debacle.
Upon arriving at Koh Rong Samloem, Captain Miller was interrogated and asked if he could call off the air strikes using the ship’s radio.
Miller explained that he could, but that he’d have to contact the company’s office in Bangkok first and ask them to relay the message to the US Embassy.
The following day Captain Miller and the crew were then taken back to Mayaguez, after which the Khmer Rouge used the ship’s radio to broadcast a message announcing that the sailors and vessel would be released.
The message also stated that the Khmer Rouge had no intention of escalating hostilities with the United States, but politely asked that the latter stop conducting espionage activities in Cambodia’s territorial waters.
The transmission was picked up by the CIA station in Bangkok, translated and delivered to the White House, but nobody was sure if the message was authentic, and the decision was made to proceed with military operations until Mayaguez and her crew were officially back in American hands.
True to their word, the Khmer Rouge delivered the crew to the destroyer USS Wilson immediately after the broadcast.
Then, American Marines retook the abandoned Mayaguez and the White House was informed that the incident had been resolved.
Just a few hours later President Ford appeared on television to pass on the good news to the American public, though he conveniently omitted that part about the Khmer Rouge releasing the ship and crew voluntarily.
Despite this positive turn of events however, at Henry Kissinger’s urging, President Ford refused to call off the airstrikes against mainland targets, at least until the Marines tasked with assaulting Koh Tang were off the island and out of harm’s way.
Now the assault on Kog Tang was even more unnecessary, but the wheels had been irreversibly set in motion.
Taking increasingly heavy fire, by the time the first wave of more than 125 Marines set their boots on the island, eight of nine helicopters involved in the mission had been shot down or severely damaged.
Ultimately, approximately 230 American soldiers would be delivered to Koh Tang from ships offshore, but now with the Mayauez situation largely resolved, they were ordered to immediately cease all offensive actions and prepare to evacuate.
But by then more than two dozen men had been killed or wounded, and the Khmer Rouge defenders had no way of knowing that the assault had been called off.
In the following hours, more than a hundred Marines were airlifted out, but many more were still on the island, and with so few helicopters and a 1+ hour round trip between the island and US Navy ships offshore, getting them evacuated would take some time.
By 2:00 PM that afternoon Marines and Khmer Rouge soldiers were still engaged in multiple firefights.
But though the majority of the Cambodian forces had retreated to the center of the island where they formed a tight perimeter around a sizable ammo dump, other smaller but well-armed units continued to harass the Americans who were isolated in open areas at East and West Beaches.
The Marines were supported by F-4s, A-7s and AC-130 gunships, but as the sun set their ability to deliver fire accurately diminished.
In the melee, helicopter pilots hovered their craft over both LZs, but in the turbulence the loading process was painfully slow, and the massive aircraft were relatively easy targets.
The first helicopter onsite took multiple hits but managed to get 20 Marines back to Coral Sea, and within the next few hours another 95 men were airlifted out.
But as the night wore on the remaining Marines were dangerously close to being overrun, and the evacuation became exponentially more dangerous and nearly ground to a halt.
Ultimately just 32 Marines were left to defend themselves against the approaching Khmer Rouge soldiers.
Most were eventually evacuated, but in the chaos it was unclear if anyone had been left behind.
Then, once everyone had regrouped back on the Navy ships, commanders discovered that three men who’d been last seen alive – Joseph Hargrove, Gary Hall, and Danny Marshall – were still unaccounted for.
Then, radio operators picked up a muffled transmission in English, during which a man asked when he and his two companions could expect the next evacuation helicopter.
Unsure if this was a ploy by the Khmer Rouge to draw more Americans into an ambush, the operator asked for and received an authentication code, confirming that the caller was who he claimed to be.
But oddly, the exhausted Marine was informed that at the moment the LZ was too hot, and that he and his cohorts should swim out to sea where they’d be rescued.
After he informed the men on the ship that only two of the three Marines could swim, the radio fell silent.
Meanwhile, planners considered a number of options to get them off, one of which was using a 14-man SEAL team to extract them under the cover of darkness.
The second option was by far the least risky, and the following morning USS Wilson cruised back and forth between the West and East Beaches broadcasting messages in both English and Khmer, informing the defenders that they had no hostile intent and only wished to evacuate the Marines, both dead and alive.
Dozens of crewmen on deck scanned the beaches and treelines, but there was no response nor any sign of any American or Khmer Rouge soldiers.
With no indication that the three Marines were still alive, Wilson departed that afternoon.
During a search of West Beach on the morning of May 16, one of Em Son’s men was shot by a concealed Marine.
The Khmer Rouge soldiers encircled the position, and after a short exchange of fire captured Joseph Hargrove who had a badly wounded leg.
When the soldier who’d been shot on the beach died, Em son ordered that Hargrove be executed, and the following morning the two remaining survivors were taken into captivity.
Shackled and stripped to their underwear, the last two Marines were taken to a pagoda near Kampong Som where they were interrogated for approximately one week.
Then, orders came directly from Phnom Penh – possibly from Pol Pot himself – and each American was beaten to death with the tube from a B-40 rocket launcher.
Hall’s body was buried in a shallow grave adjacent to a remote beach, while Marshall was dumped in a nearby cove.
In mid-1976 Hargrove, Marshall and Hall were declared Missing in Action, and later all received Purple Hearts from the Marine Corps.
Between 1991 and 1999, US and Cambodian investigators conducted seven cooperative investigations, the last of which uncovered bone fragments near where the men’s bodies had been disposed of, though DNA tests couldn’t conclusively prove if they were from the Americans.
Nearly a decade later, the Department of Defense’s POW/MIA Accounting Agency announced that Hall’s ID card and flak jacket had been recovered as well.
Officially, the United States estimated that between the assault on Koh Tang and attacks on the mainland, between 10 and 25 Khmer Rouge soldiers had been killed as a result of the Mayaguez incident.
US aircraft also destroyed a large portion of Cambodia’s Navy and Air Force, significantly weakening both leading up to the impending war with Vietnam.
In 1977 the Khmer Rouge began viciously attacking Vietnamese border provinces.
Thousands of civilians on both sides were killed, ultimately prompting Vietnam to invade Cambodia in December of 1978.
With Vietnam’s help, the Khmer Rouge were ultimately defeated, and the last Vietnamese troops wouldn’t return home until 1989.
For the Khmer Rouge leadership the Mayaguez incident reinforced their beliefs that the U.S. “imperialists” were determined to undermine their revolution at any cost.
The United States has always claimed that the Mayaguez seizure was illegal, and that it took place more than 6 miles (9.5 km) from the coast.
But afterward, the crew presented evidence purportedly showing that the ship had been just two miles (3.2 km) off the coast.
In addition, Mayaguez wasn’t flying a flag, leading some to speculate that the whole incident had been a deliberate provocation, but if that’s the case, what America hoped to achieve is anybody’s guess.
Now, the last 41 names etched into the Vietnam Veterans Memorial Wall in Washington are those of the airmen and Marines killed during the assault and evacuation of Koh Tang.
Of these, more than half were killed in the helicopter crash in Thailand in the first mission that was ultimately canceled.