Twenty-five years ago today, the American container ship Mayaguez was intercepted 60 kilometers off the Cambodian coast by Khmer Rouge naval forces and its crew taken hostage.

Four days later, 41 American soldiers and an unknown number of Cambodians were dead as a result of a failed rescue attempt on Koh Tang Island and heavy American bombardment of Sihanoukville port and nearby Ream naval base. Phelim Kyne and Chea Sotheacheath reflect on the Mayaguez Incident—the tragic final act of United States military involvement in Southeast Asia.

At 2:20 p.m. on May 12, 1975, an otherwise routine voyage to Sattahip, Thailand, by the Sealand container ship Mayaguez was halted by two Khmer Rouge naval patrol boats with heavily armed crews.

The skeletal remains of an American helicopter retrieved from the surf around Koh Tang by US MIA teams in 1995.

Accused of violating Cambodian territorial waters, the ship and its 39-member crew were redirected to the Cambodian island of Koh Tang.

Coming just 12 days after America's humiliating withdrawal from Vietnam, the hostage-taking became the focal point of US government efforts to restore a superpower reputation damaged by the recent Communist victories in Cambodia and Vietnam.

"The National Security Council was convened, and [then-US Secretary of State] Kissinger argued that much more was at stake than the seizure of an American ship ... [that] American credibility was more involved than ever," William Shawcross wrote in his book Sideshow. "Throughout the crisis, the Secretary insisted that for domestic and international reasons, and particularly to impress the North Koreans, the United States must use force."

Although the Mayaguez crew was transferred by fishing boat to the port of Sihanoukville on the afternoon of May 13, US military intelligence believed at least half the crew remained on Koh Tang, prompting plans for a rescue mission by American Marines based in Thailand.

But the operation went awry almost immediately.

A stretch of beach on Koh Tang where two of three US helicopters were shot down on the morning of May 15, 1975.

American planes, attempting to force the Khmer Rouge boat carrying the Mayaguez crew back to Koh Tang, repeatedly strafed and tear-gassed the vessel. These attacks were later the subject of an unsuccessful lawsuit by some of the crew, who cited chronic health issues resulting from the aerial assaults.

On the evening of May 14, 23 US Marines became the first fatalities of the Mayaguez Incident when their helicopter crashed en route from Nakhon Phanom Royal Thai Airbase to the departure point at U Tapao Air Base. A US government memorial unveiled in Phnom Penh in 1995 by Senator John McCain omits any mention of these men.

At dawn on May 15, 170 Marines in eight Knife and Jolly Green Giant helicopters began the first phase of the rescue mission, anticipating little or no resistance from what US intelligence had estimated as 35–40 Khmer Rouge “irregulars.”

Instead, they encountered a firestorm from a well-armed and entrenched unit of battle-hardened Khmer Rouge, veterans of the April 17 “liberation” of Phnom Penh, who launched a fierce assault using confiscated American weapons left behind by defeated Lon Nol forces.

Within minutes, three helicopters were downed. For the next 24 hours, US forces fought to survive a brutal engagement that left 16 Khmer Rouge fighters and 18 additional Americans dead. Their remains continue to be the subject of US MIA recovery efforts on Koh Tang.

In a cruel irony unknown to the Marines still battling on Koh Tang, the Mayaguez crew had already been released onto a Thai fishing boat hours before the assault began.

At 10:08 a.m. on May 15, while US helicopters took heavy fire during evacuation attempts, the Mayaguez crew was rescued by the US Navy.

Mao Ran, Khmer Rouge platoon commander on Koh Tang during the US assault of May 15, 1975.

Shawcross writes in Sideshow that President Ford quickly portrayed the operation as a victory: “... it did not only ignite confidence in the White House ... it had an electrifying reaction as far as the American people were concerned. It was a spark that set off a whole new sense of confidence for them, too.”

But weighing the cost—41 Americans killed to retrieve 39 merchant seamen, alongside the loss of Cambodian lives and destruction of infrastructure—Shawcross concludes the Mayaguez Incident left little to celebrate for anyone.

“In the attacks on [Sihanoukville] the railroad yard, the port, the oil refinery, and the airfield were virtually destroyed,” he wrote. “At Ream naval base, 364 buildings were flattened. Nine Cambodian vessels were sunk at sea. To rescue the Marines on Koh Tang, the island was heavily bombarded ... ignoring the August 1973 ban on bombing Indochina and the 1973 War Powers Act. The principal aims of the bombing seemed to be to punish the Cambodians and reassert American military strength, perceived to have been damaged by the fall of Phnom Penh and Saigon.”

At the pre-dawn briefing for the Marines designated to rescue the Mayaguez crew, the mission sounded deceptively simple.

“Our group’s mission was to land on the beach, link up with other units, and move toward the center of the island where a compound supposedly held the crew,” explained Lance Corporal Dale L. Clark, a Marine fire team leader. “We had two Army interpreters with bullhorns tasked with persuading the Khmer Rouge to surrender without a fight.”

But the mission had all the hallmarks of a disaster: inexperienced troops facing a seasoned enemy on its home ground and a gross underestimation of the opposition.

“Few in our company had any prior combat experience ... many were fresh out of boot camp,” said Marine survivor Larry Barnett. “A fair term to describe our company would be ‘greenhorns.’”

As they flew over the Gulf of Thailand toward Koh Tang, Barnett and Clark were reassured by intelligence reports of minimal resistance.

“We were told to expect sniper fire at most,” Barnett said.
“We were led to expect a simple, quick operation,” Clark added. “We were even told not to ‘lock and load’ until ordered to, since combat wasn’t expected.”

An American scholar and former military officer who has studied the operation said the Marines were misled by outdated estimates from a former Lon Nol naval officer.

“My analysis, adjusted from CIA and DIA reports and Marine accounts, is that about 200 Khmer Rouge were on the island, with heavy machine guns, mortars, and recoilless rifles,” he said. “A Khmer Rouge message intercepted after the battle mentioned 55 killed and 70 wounded.”

Clark was stunned by the ferocity of the enemy fire.

“I couldn’t believe it ... the KR opened up on the first four helicopters attempting landings,” he said. “There was smoke from rifle fire as we flew over the treetops. I saw fuel spraying inside the chopper. I just hugged the floor in disbelief.”

Clark and Barnett agree: the intelligence failure was severe.

“Being told to expect no resistance—and finding the opposite—makes this an intelligence disaster,” said Clark. “Years later, I found that some military branches had accurate intel, but it never reached us.”

Barnett added, “The intel was good, but it didn’t reach the troops. Our commanders even had photos of enemy bunkers but withheld them to avoid alarming us.”

Surprise and confusion were also felt by the Khmer Rouge. Mao Ran, a 22-year-old platoon commander who had expected Vietnamese incursions, was shocked by the US assault.

“I met the [Mayaguez] crew and treated them kindly,” Ran said. “I think the Americans attacked out of revenge for losing the war ... they bombed not just Koh Tang but also the port and airfield—it was revenge.”

Ran disputes revised US estimates of Khmer Rouge numbers.

“We had 40 men total, only 20 fought,” he said. “But we had a lot of weapons from Phnom Penh ... we used American M16s and M30s.”

Clark and Barnett doubt Ran’s numbers but respect their tenacity.

“I was so scared I had to defecate while prone, firing my weapon,” said Clark. “A snake even crawled over my leg, but I couldn’t stop firing.”

Ran, unimpressed by US tactics, said: “They weren’t professional like us ... they spoke loudly, smoked, and laughed, making it easy to find and attack them.”

From the air, American planes and gunships saturated the island with cover fire, including a massive 15,000-pound BLU-82 bomb that left a crater still visible today.

“I think the Americans assumed we were all dead,” said Ran. “They flew low, and we shot at them.”

After the last Marines withdrew at dawn on May 16, Ran and others dragged dead Marines to the water and threw them in. “I dragged five or six myself,” he recalled.

Referencing later US efforts to recover remains, he joked: “If we knew they’d come back, we’d have put the bodies in one spot.”

Ran has no sympathy for US losses, citing Cambodian casualties.

“We lost six on the island and ten more when their boats were sunk,” he said. “Many more died from the bombings.”

Clark and Barnett, haunted by Koh Tang, said they would like to meet their former foes someday.

“I’d love to ask what they were feeling,” Clark said.

Ran, however, is less inclined.

“Koh Tang was like training,” he said. “The real victory was liberating Phnom Penh. People say we killed a million [1975–1979], but the Americans killed another million in B-52 attacks ... I saw whole villages destroyed—I’ll never forget that.”