How Did A Mark 15 Nuclear Bomb End Up At The Bottom of Wassaw Sound?

Photo Credit: 1. US Military / Wikimedia Commons / Public Domain 2. US Atomic Energy Commission / Wikimedia Commons / Public Domain
Photo Credit: 1. US Military / Wikimedia Commons / Public Domain 2. US Atomic Energy Commission / Wikimedia Commons / Public Domain

Off the shores of Tybee Island, near Savannah, Georgia, a lost Mark 15 nuclear bomb rests, accidentally released by a US Air Force aircraft during a crisis in the 1950s. Today, it remains submerged in the depths of Wassaw Sound, awaiting either discovery or the potential for detonation.

This situation is concerning. While initial reports suggested that the bomb’s nuclear core had been removed, later records indicate it remains intact within the device. Consequently, the Mark 15 continues to pose a potential hazard to the local residents.

Mid-air collision over Tybee Island

Mark 15 nuclear bomb on a dolly
Mark 15 nuclear bomb. (Photo Credit: US Atomic Energy Commission / Wikimedia Commons / Public Domain)

On February 5, 1958, while performing a simulated combat mission exercise, a Boeing B-47 Stratojet was involved in a mid-air collision with a North American F-86 Sabre. The B-47, having taken off from Homestead Air Force Base, Florida, was carrying a two-man crew, as well as a 7,600-pound Mark 15 nuclear bomb.

The F-86’s pilot, Lt. Clarence Stewart, hadn’t seen the B-47 on his radar and descended directly on top of it. The crash between the two caused the left wing of the fighter jet to completely rip off, while the bomber’s fuel tanks suffered heavy damage. Stewart was able to eject before his aircraft crashed, while the pilot of the B-47, Lt. Col. Howard Richardson, sought the closest landing base. Despite the damages to the bomber, the B-47 remained airborne. After dropping 18,000 feet, Richardson regained control.

As for the nuclear bomb onboard the aircraft, he granted the crew’s request to jettison it, to prevent it from exploding during the emergency landing. The bomb was dropped from 7,200 feet, over the shores of Tybee Island. The pilot and crew reported no explosion upon it meeting the water, and they were able to successfully land the damaged B-47 at Hunter Army Airfield, Georgia.

For his actions, Richardson was awarded the Distinguished Flying Cross.

A search force was sent to find the bomb

Boatswain's Mate 2nd Class Arick Hiles handing a compact sonar unit to Damage Controlman First Class Ralph Leete
Photo Credit: Chief Photographer’s Mate Eric J. Tilford / U.S. Navy / Wikimedia Commons / Public Domain

The day after the collision, the mission to locate the missing bomb began under the oversight of the US Air Force’s 2700th Explosive Ordnance Disposal Squadron, supported by 100 US Navy personnel. The search took place in the waters off Tybee Island, specifically in Wassaw Sound. Using handheld sonar devices and conducting comprehensive cable sweeps, the operation lasted nearly 10 weeks. Unfortunately, on April 16, the military announced they were unable to find the explosive.

In 2001, the Department of Energy carried out a hydrographic survey of Wassaw Sound, suggesting the potential location of the Mark 15. The survey indicated that the bomb was buried under five to 15 feet of silt. The military used this information to approximate the bomb’s location.

Was the Mark 15 nuclear?

Paper featuring an image of a Mark 15 Mod 2 nuclear bomb
Mark 15 Mod 2 nuclear bomb. (Photo Credit: AEC / DoD / Wikimedia Commons / Public Domain)

Ever since its disappearance, experts have argued over whether the weapon was nuclear or not. If it had a plutonium core, then it was a fully-functional nuclear weapon. If not, then the core was replaced with a dummy, making it non-nuclear, but still capable of producing a conventional explosion.

The Air Force assured the public that the Mark 15’s “nuclear capsule” was removed prior to the flight and fitted with a simulated 150-pound cap made of lead. Strategic Air Command documents reinforced this sentiment, explaining that test flights in February 1958 weren’t authorized to fly with nuclear capsules fitted into their bombs.

For a long time, this explanation was accepted. However, in 1994, a previously-classified document featuring the transcript from the 1966 Congressional testimony of then-Assistant Secretary of Defense W.J. Howard became unclassified, which contradicted what the Air Force had assured the public for years.

Speaking to the US Congressional Joint Committee on Atomic Energy, Howard confessed the Mark 15 was a “complete, fully functional bomb with a nuclear capsule,” containing a plutonium trigger. If Howard’s testimony is correct, then the bomb may still cause significant damage to the surrounding area, if detonated. The explosion would include a fireball reaching over a mile and thermal radiation detection as far as 10 miles in all directions.

Yet another search is launched

Chunk of Monazite placed on a table
Monazite, the element increasing radiation levels in the water where searchers believed the Mark 15 bomb was located. (Photo Credit: DEA / A. RIZZI / De Agostini / Getty Images)

Armed with the latest data, Air Force veteran Lt. Col. Derek Duke privately conducted a new search for the missing nuclear bomb in 2004. Together with his team, they meticulously explored the Wassaw Sound area, using a Geiger counter to measure radiation levels in the water.

Their efforts uncovered that near Tybee Island’s summit, radiation levels were four times higher than normal, suggesting a possible location of the Mark 15 if it were indeed nuclear. By identifying these heightened radiation areas, they could delineate and triangulate a region about the size of a football field.

However, subsequent Air Force analysis of the site concluded that the elevated radiation resulted from natural sources, specifically monazite deposits in the sand. Consequently, the whereabouts of the elusive Mark 15 remain a mystery.

Best to leave the nuclear bomb alone

Diagram featuring a Mark 15 nuclear bomb
Mark 15 nuclear bomb. (Photo Credit: AEC / DoD / Wikimedia Commons / Public Domain)

The Air Force is content with leaving the bomb’s location a mystery, and officials have assured residents in the surrounding area that it poses no threat, so long as it’s left alone. An “intact explosive would pose a serious explosion hazard to personnel and the environment if disturbed by a recovery attempt,” they stated.

More from us: Mars Bluff Incident: The US Air Force Accidentally Dropped a Nuclear Bomb on South Carolina

The next time you go diving near Tybee Island, keep an eye out for the 12-foot long, 7,600-pound Mark 15 nuclear bomb with the serial number 47782. If you spot it, leave the sleeping beast alone!

Samantha Franco

Samantha Franco is a Freelance Content Writer who received her Bachelor of Arts degree in history from the University of Guelph, and her Master of Arts degree in history from the University of Western Ontario. Her research focused on Victorian, medical, and epidemiological history with a focus on childhood diseases. Stepping away from her academic career, Samantha previously worked as a Heritage Researcher and now writes content for multiple sites covering an array of historical topics.

In her spare time, Samantha enjoys reading, knitting, and hanging out with her dog, Chowder!

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