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Remembering Resistance: U.S. Navy POWs at the Hanoi Hilton

Sept. 18, 2024 | By Wendy Arevalo, NHHC Communication and Outreach Division
Lt. Cmdr. Everett Alvarez, Jr. speaks to the crowd during a welcome-home ceremony in February 1973 (photo on display at Hoa Lo Prison Relic in Hanoi, Vietnam). Alvarez was a prisoner of war (POW) for the entire duration of the Vietnam War—making him the longest-held POW in North Vietnam. He was released on Feb. 12, 1973 (courtesy of Shawn Vreeland).
Lt. Cmdr. Everett Alvarez, Jr. speaks to the crowd during a welcome-home ceremony in February 1973 (photo on display at Hoa Lo Prison Relic in Hanoi, Vietnam). Alvarez was a prisoner of war (POW) for the entire duration of the Vietnam War—making him the longest-held POW in North Vietnam. He was released on Feb. 12, 1973 (courtesy of Shawn Vreeland).
Lt. Cmdr. Everett Alvarez, Jr. speaks to the crowd during a welcome-home ceremony in February 1973 (photo on display at Hoa Lo Prison Relic in Hanoi, Vietnam). Alvarez was a prisoner of war (POW) for the entire duration of the Vietnam War—making him the longest-held POW in North Vietnam. He was released on Feb. 12, 1973 (courtesy of Shawn Vreeland).
Lt. Cmdr. Everett Alvarez, Jr. speaks to the crowd
Lt. Cmdr. Everett Alvarez, Jr. speaks to the crowd during a welcome-home ceremony in February 1973 (photo on display at Hoa Lo Prison Relic in Hanoi, Vietnam). Alvarez was a prisoner of war (POW) for the entire duration of the Vietnam War—making him the longest-held POW in North Vietnam. He was released on Feb. 12, 1973 (courtesy of Shawn Vreeland).
Photo By: U.S. Navy
VIRIN: 240916-N-WA001-001
On Aug. 5, 1964, Lt. j.g. Everett Alvarez, Jr., a young U.S. Navy aviator, had just finished bombing a North Vietnamese patrol boat base in retaliation for the Tonkin Gulf Incident when his Douglas A-4 Skyhawk was struck by enemy fire. After ejecting, he was captured by Vietnamese militia, then interrogated by North Vietnamese officers before being taken to Hoa Lo Prison (later known as the “Hanoi Hilton”) in Hanoi. He was the first naval aviator and first American to be held in North Vietnam. He would spend the next eight and a half years in captivity.

Alvarez is just one of the nearly 600 American prisoners of war (POWs) captured during the Vietnam War. Of those, one-fourth were Navy, mostly naval aviators. Several were senior officers, tasked with setting the example of resistance for the rest of the POWs to follow.

Operation Rolling Thunder, launched in the spring of 1965, was the impetus for nearly a dozen of the earliest captures of Navy POWs. Operation Rolling Thunder was an aerial campaign that stepped up bombing efforts in North Vietnam. The operation’s “graduated response” strategy proved to be ineffective and resulted in high casualties. By the summer of 1965, more than 30 American aviators had been killed, were missing in action, or had been captured. Among those who had been captured were three senior naval officers: Lt. Cmdr. Robert Shumaker, Cmdr. Jeremiah Denton, and Cmdr. James Stockdale.

These early captured aviators, along with several others, would go on to lead an eight-year battle of resistance from behind prison walls.

Alvarez spent the majority of his time at Hoa Lo in a section of the prison Americans dubbed “Heartbreak Hotel,” where new arrivals were in-processed, screened, and interrogated. From mid-September 1965 to early November, he endured eight hours of questioning per day by experienced North Vietnamese political officers skilled in the use of mind manipulation techniques borrowed from the Chinese Communists. Enemy intelligence reports later revealed that during this evaluation stage, the Vietnamese interrogators also documented their first impressions of a POW’s behavior and attitude in a preliminary personal record. This record was used as a guide for future treatment, including camp assignments and whether the prisoner should be held in solitary confinement or placed with others.

Alvarez lost 40 pounds in the first few weeks of captivity due to the inedible prison food, which included animal hooves, chicken heads, rotten fish, and pieces of meat covered with hair. He suffered from constant vomiting and diarrhea. After seeing how ill he was, the North Vietnamese began giving him rice soup, which stopped his vomiting.

After resisting efforts by the North Vietnamese to reveal sensitive information, he was left in isolation in a remote area of the prison away from other prisoners. By 1965, he had gone a year without any contact with another American and was in low spirits. That summer, he was moved to a smaller cell closer to other prisoners. By this time, many other POWs had arrived and had started to develop a communication system. In August 1965, Alvarez made contact with another POW by scratching a note on a kitchen utensil. He was quickly inducted into the underground prison communication network. In August 1965, due to overcrowding at Hoa Loa, Alvarez was moved to the “Zoo,” another detention center in the North Vietnamese prison system.

Robert Shumaker was the next American to arrive at Hoa Lo. He was seized on Feb. 11, 1965, after his aircraft was hit by ground fire. He suffered a compression fracture of his lower back after bailing out at a low level and landing in the sitting position. This injury, which was untreated, caused him great pain over the next eight years.
Lt. j.g. Everett Alvarez, Jr., in his striped prison uniform, talks with a Vietnamese prison guard while in downtown Hanoi, North Vietnam, ca. 1967. Vietnamese prison guards routinely escorted American POWs around town to view nationalist- and Communist-themed museum exhibits and other landmarks. They were often paraded before crowds of angry Vietnamese townspeople and photographed for propaganda purposes (Office of the Secretary of Defense).
Lt. j.g. Everett Alvarez, Jr., in his striped prison uniform, talks with a Vietnamese prison guard while in downtown Hanoi, North Vietnam, ca. 1967. Vietnamese prison guards routinely escorted American POWs around town to view nationalist- and Communist-themed museum exhibits and other landmarks. They were often paraded before crowds of angry Vietnamese townspeople and photographed for propaganda purposes (Office of the Secretary of Defense).
Lt. j.g. Everett Alvarez, Jr., in his striped prison uniform, talks with a Vietnamese prison guard while in downtown Hanoi, North Vietnam, ca. 1967. Vietnamese prison guards routinely escorted American POWs around town to view nationalist- and Communist-themed museum exhibits and other landmarks. They were often paraded before crowds of angry Vietnamese townspeople and photographed for propaganda purposes (Office of the Secretary of Defense).
Lt. j.g. Everett Alvarez, Jr., in his striped prison uniform
Lt. j.g. Everett Alvarez, Jr., in his striped prison uniform, talks with a Vietnamese prison guard while in downtown Hanoi, North Vietnam, ca. 1967. Vietnamese prison guards routinely escorted American POWs around town to view nationalist- and Communist-themed museum exhibits and other landmarks. They were often paraded before crowds of angry Vietnamese townspeople and photographed for propaganda purposes (Office of the Secretary of Defense).
Photo By: U.S. Navy
VIRIN: 240916-N-WA001-002

Lt. Cmdr. Robert Shumaker, shown here at the time of his capture in February 1965. He was the second U.S. Navy pilot shot down in North Vietnam. He and an Air Force officer, Capt. Carlyle Harris, created the “tap code,” which became a lifeline to American POWs (reprinted from The Battle Behind Bars, Naval Historical Foundation/Naval History and Heritage Command [NHHC], Washington, DC, 2010).
Lt. Cmdr. Robert Shumaker, shown here at the time of his capture in February 1965. He was the second U.S. Navy pilot shot down in North Vietnam. He and an Air Force officer, Capt. Carlyle Harris, created the “tap code,” which became a lifeline to American POWs (reprinted from The Battle Behind Bars, Naval Historical Foundation/Naval History and Heritage Command [NHHC], Washington, DC, 2010).
Lt. Cmdr. Robert Shumaker, shown here at the time of his capture in February 1965. He was the second U.S. Navy pilot shot down in North Vietnam. He and an Air Force officer, Capt. Carlyle Harris, created the “tap code,” which became a lifeline to American POWs (reprinted from The Battle Behind Bars, Naval Historical Foundation/Naval History and Heritage Command [NHHC], Washington, DC, 2010).
Lt. Cmdr. Robert Shumaker
Lt. Cmdr. Robert Shumaker, shown here at the time of his capture in February 1965. He was the second U.S. Navy pilot shot down in North Vietnam. He and an Air Force officer, Capt. Carlyle Harris, created the “tap code,” which became a lifeline to American POWs (reprinted from The Battle Behind Bars, Naval Historical Foundation/Naval History and Heritage Command [NHHC], Washington, DC, 2010).
Photo By: U.S. Navy
VIRIN: 240916-N-WA001-003
Shumaker spent his first few months in solitary confinement, but in May 1965, three other American officers were moved into Shumaker’s cell due to overcrowding. Shumaker, the senior officer in Hoa Lo at the time, suggested they develop a communication system that would allow them to stay in contact and organize the resistance effort. Air Force Capt. Carlyle Harris remembered a code he had learned in survival school that American prisoners had used in North Korean POW camps. It would come to be known as the “tap code,” as prisoners would use their tin drinking cups, or other objects, to tap messages. The code utilized a five-by-five grid containing all letters of the alphabet (with the exception of “K” as there were only 25 squares, one for each letter).

Tap Code. Reprinted from The Battle Behind Bars, Naval Historical Foundation/NHHC, Washington, DC, 2010.
Tap Code. Reprinted from The Battle Behind Bars, Naval Historical Foundation/NHHC, Washington, DC, 2010.
Tap Code. Reprinted from The Battle Behind Bars, Naval Historical Foundation/NHHC, Washington, DC, 2010.
Tap Code. Reprinted from The Battle Behind Bars, Naval Historical Foundation/NHHC, Washington, DC, 2010.
Tap Code. Reprinted from The Battle Behind Bars, Naval Historical Foundation/NHHC, Washington, DC, 2010.
Photo By: U.S. Navy
VIRIN: 240916-N-WA001-004
Each letter was transmitted by using two numbers. First, they would indicate by tapping the number of the letter’s horizontal row, pause, and tap out the number of the letter’s vertical column. So, for example, “D” would be one tap, a pause, and then four more taps in rapid succession.

The tap code became a lifeline to the POWs, some of whom hadn’t been able to communicate with another American for months due to being kept under strict watch by guards. They used the code to share information on new arrivals, personalities and habits of guards, information from the outside, or just to converse and provide mutual support.  

Alvarez, who was separated from his fellow prisoners for a year before learning about the tap code, said the support from his fellow POWs helped him survive his long imprisonment. “We had a philosophy that you didn't ever let your fellows down,” he said in a September 2015 Montgomery County, Maryland, commemorative press release. “If they couldn't take care of themselves, you took care of them because you knew darned well they would do the same. And we had a goal. We were determined to come home with our personal integrity, our reputation and with our honor.”

Shortly after Shumaker and his cellmates introduced the tap code, Jeremiah Denton arrived. Like Shumaker, Denton arrived in an injured state. He had snapped a tendon in his leg while struggling to control his aircraft before it went down. He was also struck in the neck with a machete by two Vietnamese men in a dugout as he attempted to evade capture by floating down the Ma River.

Now the senior POW in Hoa Lo, Denton began issuing instructions after being familiarized with prison operations by the other POWs. For instance, everyone would observe the Code of Conduct established in 1955 and comply with resistance tactics issued by Denton (i.e., hunger strikes, etc.). He was to be kept informed of important events, such as shoot downs, so he would have an accurate idea of the prison population. He also ordered that prisoners should try and wash whenever there was an opportunity to avoid the spread of dysentery.
Denton was placed in leg stocks shortly after his arrival. He was caught trying to pry a metal bar off the set of stocks attached to his bed. (He had planned to use the bar to break through his window screen and escape).

Mannequins at the Hoa Lo Prison Relic displaying leg stocks. Each cell in Hoa Lo had a cement bed and stocks that were used to hold prisoners for months at a time as a means of punishment. The POWs found the stocks to be particularly painful as they were undersized for the average American. Members in solitary confinement at “Alcatraz,” a small prison near Hoa Lo reserved for strong resistors, were locked into the stocks every night, sometimes for years at a time (courtesy of Shawn Vreeland).
Mannequins at the Hoa Lo Prison Relic displaying leg stocks. Each cell in Hoa Lo had a cement bed and stocks that were used to hold prisoners for months at a time as a means of punishment. The POWs found the stocks to be particularly painful as they were undersized for the average American. Members in solitary confinement at “Alcatraz,” a small prison near Hoa Lo reserved for strong resistors, were locked into the stocks every night, sometimes for years at a time (courtesy of Shawn Vreeland).
Mannequins at the Hoa Lo Prison Relic displaying leg stocks. Each cell in Hoa Lo had a cement bed and stocks that were used to hold prisoners for months at a time as a means of punishment. The POWs found the stocks to be particularly painful as they were undersized for the average American. Members in solitary confinement at “Alcatraz,” a small prison near Hoa Lo reserved for strong resistors, were locked into the stocks every night, sometimes for years at a time (courtesy of Shawn Vreeland).
Mannequins at the Hoa Lo Prison Relic displaying leg stocks
Mannequins at the Hoa Lo Prison Relic displaying leg stocks. Each cell in Hoa Lo had a cement bed and stocks that were used to hold prisoners for months at a time as a means of punishment. The POWs found the stocks to be particularly painful as they were undersized for the average American. Members in solitary confinement at “Alcatraz,” a small prison near Hoa Lo reserved for strong resistors, were locked into the stocks every night, sometimes for years at a time (courtesy of Shawn Vreeland).
Photo By: U.S. Navy
VIRIN: 240916-N-WA001-005
In the fall of 1965, prison guards became aware of the tap code and the resistance effort. Under pressure to gain information and confessions from the prisoners, they began increasingly brutal methods to extract information from POWs, eventually resorting to torture. One of the most dreaded forms of torture was the rope treatment—which some prisoners called “taking the ropes.”

In this excruciating form of torture, a prisoner would be placed in a sitting position with his ankles bound in leg irons while his wrists and elbows were bound tightly together behind his back and pulled up to the back of the head. A prison guard then would plant his foot between the POW’s shoulder blades to apply leverage and pull hard until the prisoner’s arms were up and back over his head, forcing it down between his feet. To intensify the pain, guards sometimes walked on the prisoners’ backs to further cut off their upper body circulation.

The North Vietnamese justified the torture by stating that they didn’t need to abide by the Geneva Conventions because the Vietnam War was an undeclared war and they labeled the POWs “air pirates,” mercenaries, or criminals. They further ignored the Geneva Convention protocols by exploiting the POWs for propaganda purposes, particularly the senior officers. When Denton was forced against his will to participate in a televised video interview with a Japanese reporter, he blinked the letters T-O-R-T-U-R-E in Morse code. The message was picked up by U.S. naval intelligence, providing the first clue that the POWs were being tortured. For this and other defiant acts while in captivity, Denton was later awarded the Navy Cross.

Denton relinquished command of the North Vietnam POW prison network to James Stockdale when the latter arrived at the Hanoi Hilton in September 1965. (Stockdale was only senior to Denton based on his Naval Academy class standing). Before his capture, Stockdale had been commanding officer of Carrier Air Group 16 and had led the first air raids after the August 1964 Tonkin Gulf Incident, raids in which Alvarez had participated.

Stockdale would go on to serve as the senior officer for all the POWs imprisoned in the North Vietnam prison system. He urged prisoners to resist cooperating with their captors but understood that only so much could be expected of the POWs when they were subjected to torture. He found it unrealistic for the POWs to only reveal name, rank, serial number, and date of birth as set out in the 1955 Code of Conduct. Stockdale believed that the POWs should follow the Code of Conduct in principle, but improvise based on their experience, since the Vietnamese were not abiding by the tenets of the Geneva Convention. He and the other senior officers created internal guidelines for survival and resistance that he disseminated to all POWs.

 “We set a line of resistance which we thought was in every POWs capability to hold, and we [the leaders] ruled that no man would cross that line without significant torture,” stated Stockdale in Honor Bound, Stuart Rochester and Frederick Kiley’s history of U.S. POWs in Vietnam.
 
Stockdale led the resistance effort by deed and example. Over his seven and a half years of captivity, he was tortured 15 times, held in solitary confinement for four years, and shackled in leg irons for two.
 
Another hardline resister of note was Lt. Cmdr. John S. McCain, who arrived two years after Stockdale. He was captured on Oct. 26, 1967, after his A-4 was shot down during an air strike against a Hanoi thermal power plant.

Vietnamese civilians surround Lt. Cmdr. John S. McCain, center, as he floats in Truc Bach Lake, in Hanoi, North Vietnam, after ejecting from his damaged aircraft, Oct. 26, 1967. He was pulled to shore, then transported to Hoa Lo Prison in Hanoi (Library of Congress).
Vietnamese civilians surround Lt. Cmdr. John S. McCain, center, as he floats in Truc Bach Lake, in Hanoi, North Vietnam, after ejecting from his damaged aircraft, Oct. 26, 1967. He was pulled to shore, then transported to Hoa Lo Prison in Hanoi (Library of Congress).
Vietnamese civilians surround Lt. Cmdr. John S. McCain, center, as he floats in Truc Bach Lake, in Hanoi, North Vietnam, after ejecting from his damaged aircraft, Oct. 26, 1967. He was pulled to shore, then transported to Hoa Lo Prison in Hanoi (Library of Congress).
Vietnamese civilians surround Lt. Cmdr. John S. McCain, center, as he floats in Truc Bach Lake, in Hanoi, North Vietnam
Vietnamese civilians surround Lt. Cmdr. John S. McCain, center, as he floats in Truc Bach Lake, in Hanoi, North Vietnam, after ejecting from his damaged aircraft, Oct. 26, 1967. He was pulled to shore, then transported to Hoa Lo Prison in Hanoi (Library of Congress).
Photo By: U.S. Navy
VIRIN: 240916-N-WA001-006
He broke his right leg and both his arms as he ejected at high speed. After landing in a lake and nearly drowning under the weight of his heavy flight gear, he was pulled from the water by enemy soldiers, who took him to Hoa Lo Prison.

Soon after the North Vietnamese found out he was the son of Admiral John S. McCain, Jr., at the time the commander in chief of U.S. Naval Forces, Europe, he was taken to a hospital for treatment as they planned to use him for propaganda purposes. Upon McCain’s release, he was transported to the “Plantation,” the clean and sanitized “show” prison that the North Vietnamese used for propaganda purposes.
 
Once McCain’s father was named Commander in Chief, Pacific Command, which included all U.S. forces in the Vietnam theater of operations, the North Vietnamese offered the younger McCain an early release. McCain refused, even though he could have accepted his captors’ offer under the rules of the Code of Conduct since he was still suffering from his injuries and had severe dysentery.
 
“It wasn’t an easy decision because I was in very poor physical health, but I also knew that the Code of Conduct said the sick and injured go first, and then by order of capture. Everett Alvarez had been there three years before I ever got there. Unfortunately, I didn’t have much communication except with the guy in the cell next to me so I had no contact with the senior ranking officer but I made the decision that it was better for me to go home in order. I’m very happy that I didn’t know I would be there another three years,” McCain said in an oral history interview.
 
As punishment for refusing early release, McCain was subjected to a year of brutality. His left arm was rebroken, and he was tied in ropes and beaten every two to three hours until he signed a confession of criminal wrongdoing and an apology to the Vietnamese people.
 
He spent two years in solitary confinement at the Plantation, enduring three and a half years without speaking to an American until civilian U.S. Agency for International Development contract pilot Ernie Brace arrived in the cell next to his. Both knew the tap code, and McCain said they used the wall between them “like a confessional booth.”
 
After his forced confession in September 1968, McCain never revealed any more information to his captors. A quick-thinking and an inventive resistor, he supplied only false or useless information during interrogations. In one instance, when pressed to give the names of the members of his aircraft squadron, he listed names of the Green Bay Packers offensive line.
 
Following Ho Chi Minh’s death in September 1969, the treatment of POWs improved dramatically. The North Vietnamese relaxed regulations and punishment and allowed the POWs to receive mail and packages (previously, for propaganda purposes, only certain senior officers like Stockdale had been allowed to send letters, but those had been heavily screened). They were given larger portions of food, a daily third meal, extra blankets and clothing, and torture ceased. Prisoners were allowed to exercise and meet each other in person after years of hearing only each other’s voices or communicating through the tap code. They were allowed to shave and supplied occasionally with hot water. By the end of the year, all the aviators were placed together in a single camp at Hoa Lo, which they named “Camp Unity.”

In January 1973, the North Vietnamese announced to the Camp Unity POWs that a truce had been initialed in the ongoing Paris peace talks and an agreement signed on prisoner repatriation. Beginning in February, as part of Operation Homecoming, 138 Navy POWs were released in four stages, with Alvarez’s group being the first to leave.

Upon returning home, Alvarez, Shumaker, Denton, Stockdale, and McCain all resumed their naval careers. They were all heavily decorated for their POW service and heroism; each was awarded two Purple Hearts and a Silver Star. Stockdale was awarded the Medal of Honor for deliberately inflicting a near-fatal wound to himself rather than capitulate. This act, which occurred in 1969, virtually stopped the torture of the POWs.
Former POWs U.S. Navy Capt. Jeremiah A. Denton, right, and U.S. Navy Capt. James A. Alfred Mulligan, left, talk during their flight on a Military Airlift Command C-141 Starlifter after being released by the North Vietnamese in February 1973 (National Archives and Records Administration 330-CFD-DD-ST-99-04242).
Former POWs U.S. Navy Capt. Jeremiah A. Denton, right, and U.S. Navy Capt. James A. Alfred Mulligan, left, talk during their flight on a Military Airlift Command C-141 Starlifter after being released by the North Vietnamese in February 1973 (National Archives and Records Administration 330-CFD-DD-ST-99-04242).
Former POWs U.S. Navy Capt. Jeremiah A. Denton, right, and U.S. Navy Capt. James A. Alfred Mulligan, left, talk during their flight on a Military Airlift Command C-141 Starlifter after being released by the North Vietnamese in February 1973 (National Archives and Records Administration 330-CFD-DD-ST-99-04242).
Former POWs U.S. Navy Capt. Jeremiah A. Denton, right, and U.S. Navy Capt. James A. Alfred Mulligan, left, talk during their flight
Former POWs U.S. Navy Capt. Jeremiah A. Denton, right, and U.S. Navy Capt. James A. Alfred Mulligan, left, talk during their flight on a Military Airlift Command C-141 Starlifter after being released by the North Vietnamese in February 1973 (National Archives and Records Administration 330-CFD-DD-ST-99-04242).
Photo By: U.S. Navy
VIRIN: 240916-N-WA001-007

 
Further Reading
Langer, Emily. “Jeremiah A. Denton Jr., Vietnam POW and Former U.S. Senator, dies at 89.” Washington Post, March 28, 2014.
McCain, John S., and Michele I. Kelly. John S. McCain III Collection. Video. Library of Congress, Jan. 29, 2003.
Montgomery County, Maryland, “Everett Alvarez, Jr., POW for 8 1/2 years, to be among Speakers as Montgomery County Honors Vietnam Veterans on Sat. Oct. 24,” news release no. 15-273, Sept. 10, 2015.
Rochester, Stuart I. The Battle Behind Bars: Navy and Marine POWs in the Vietnam War. Washington, DC: Naval History and Heritage Command, 2010.
Rochester, Stuart I., and Frederick Kiley. Honor Bound: American Prisoners of War in Southeast Asia, 1961–1973. Washington, DC: Historical Office, Office of the Secretary of Defense, 1998.
Stockdale, James B. Stockdale on Stoicism I: The Stoic Warrior’s Triad. Annapolis, MD: Center for the Study of Professional Military Ethics, U.S. Naval Academy, 1995.
Stockdale, James B. Stockdale on Stoicism II: Master of My Fate. Annapolis, MD: Center for the Study of Professional Military Ethics, U.S. Naval Academy, 1995.
Vice Admiral James B. Stockdale,” Stockdale Center for Ethical Leadership, United States Naval Academy.
Vietnam Veterans Memorial Fund. “Robert Shumaker: The Hanoi Hilton and the Creation of the Tap Code.” Facebook (video). Sept. 19, 2019.