Near Tybee Island, close to Savannah, Georgia, a missing Mark 15 nuclear bomb sits underwater, accidentally dropped from a US Air Force aircraft during a 1950s crisis. Today, it remains hidden in the depths of Wassaw Sound, still awaiting either discovery or potential detonation.
This situation is worrisome. Early reports claimed that the bomb’s nuclear core had been removed, but later documents indicate that it is still inside the device. Because of this, the Mark 15 remains a potential threat to the local population.
Mid-air collision over Tybee Island
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
The day following the collision, a search operation was started to find the missing bomb. Spearheaded by the US Air Force’s 2700th Explosive Ordnance Disposal Squadron and supported by 100 US Navy personnel, the efforts were concentrated on the waters near Tybee Island, particularly Wassaw Sound. The team employed handheld sonar devices and performed extensive cable sweeps, with the search lasting almost 10 weeks.
Unfortunately, on April 16, the military declared that the explosive device remained unfound.
In 2001, the Department of Energy conducted a hydrographic survey of Wassaw Sound, which provided hints regarding the potential location of the Mark 15. The survey suggested that the bomb was buried under five to 15 feet of silt, helping the military in approximating the bomb’s location.
Was the Mark 15 nuclear?
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
Armed with updated data, Air Force veteran Lt. Col. Derek Duke privately conducted a new search for the missing nuclear bomb in 2004. Alongside his team, they meticulously explored the Wassaw Sound area, using a Geiger counter to measure radiation levels in the water.
Their efforts revealed that radiation levels near the peak of Tybee Island were significantly elevated, about four times higher than normal, potentially indicating the presence of the Mark 15 if it was indeed nuclear. By pinpointing these areas of heightened radiation, they could narrow down and map a zone roughly the size of a football field.
However, later Air Force analysis of the site concluded that the increased radiation came from natural sources, particularly monazite deposits in the sand. Consequently, the exact location of the elusive Mark 15 remains unresolved.
Best to leave the nuclear bomb alone
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.
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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!