They left after dark: three convicted bank robbers with nothing to lose, willing to risk their lives on a makeshift raft rather than spend one more night in the world's most infamous prison.
They used spoons to dig holes in their cells, and left dummy heads in their beds to cover their tracks. Then they jerry-rigged an inflatable raft made out of raincoats, and set out on the waters of San Francisco Bay.
That's how Frank Morris, John Anglin and Clarence Anglin escaped from Alcatraz prison on June 11, 1962.
What happened next remains shrouded in mystery, but a team of Dutch researchers say there's a chance the convicts could have survived the treacherous waters of San Francisco Bay and paddled to freedom.
Delft University professors Rolf Hut and Oliver Hoes used tidal records and a three-dimensional simulation to chart all the possible routes the convicts might have taken on their raft in San Francisco Bay that night. They worked together with tidal expert Fedor Baart to produce a simulation showing all the paths the raincoat raft might have taken – and which paths might have led to freedom.
"In the worst case the paddling of the escapees is futile," Hut said in a blog post.
"The escapees are either swept into the Pacific (Ocean) if they entered the water before 23:00 (11 p.m.), or they are pushed deep into the bay and discovered if they enter the water after midnight."
Nicknamed "The Rock," Alcatraz Federal Penitentiary sits in the middle of San Francisco Bay by the Pacific Ocean. Administrators often said it was impossible to escape from Alcatraz, partly because of the treacherous waters surrounding the island.
The Dutch researchers simulated those treacherous waters and "launched" a raft every 30 minutes between 8 p.m. and 4 a.m., charting every possible course with and without paddling factored in. Hut says the convicts could only have survived if they launched their raft between 11 p.m. and midnight. Then, with a bit of luck and a lot of paddling, they might have made landfall near the Golden Gate Bridge.
Hut says the simulation was inspired by an episode of the show “Mythbusters,” in which one of the hosts showed it was possible to ride a raft from Alcatraz to shore. “Mythbusters” made landfall at about the same point indicated in the Dutch simulation, Hut said.
The fate of Morris and the Anglin brothers has remained a mystery for over 50 years. Much of what's known about the escape comes from former Alcatraz inmate Allen West. He was involved in the plot and had every intention of leaving with Morris and the Anglin brothers, but he couldn't get out of his cell in time and was left behind.
The plan was to dig through the walls of their cells with sharpened spoons, then run down an access tunnel to the Alcatraz shore. The inmates used 50 standard-issue raincoats and some cement to make their raft, then inflated it before escaping into the bay.
They left dummy heads on their beds made of soap, paper and hair.
While the fate of the three convicts is unknown, they remain the only men ever to escape from Alcatraz.
The prison housed some of the most infamous prisoners in U.S. history, including mobster Al Capone.
The prison was closed on March 21, 1963, less than a year after Morris and the Anglins escaped.
"The Rock" is now a tourist attraction.
