Hang Loose: Why WWII Frogmen Used Surfboards for Commando Operations

April 6, 2022Matt Fratus
Frogmen WWII surfboards coffee or die

Allied frogmen from the Office of Strategic Services Maritime Unit and, later, Underwater Demolition Team 10 used surfboards to transport demolitions equipment and themselves during commando operations in World War II. Photos by Matt Fratus. Composite by Coffee or Die Magazine.

In July 1944, a scrappy group of American and Italian frogmen were tasked with a daring nighttime raid behind enemy lines near the Italian city of Pesaro. It was a force of combat swimmers from the Office of Strategic Services Maritime Unit (MU) and frogmen from Italy’s San Marco Battalion — highly trained saboteurs and boat handlers who switched sides in World War II’s later years to fight for the Allies. The team planned to infiltrate enemy territory via the Adriatic Sea and sabotage a pair of bridges vital to German supply lines.

As the 12-member commando force neared the coastline, they exited their motorboats and slipped into two rubber boats and onto one electric surfboard for the final leg of their infiltration. The quiet rubber boats and electric surfboard ensured the small raiding force avoided detection.

Lt. John Chrislow, an officer assigned to the OSS MU, led the frogmen past four Nazi armored cars, two tanks, several heavy vehicles, and three German sentries patrolling the area on foot. Once on land, the team penetrated 10 kilometers into Axis territory and planted 600 pounds of plastic explosives on their targets to cripple the mobility of tanks, artillery, and troops.

flying mattresses udt oss coffee or die
The two-man surfboard, or “flying mattress,” carries swimmers equipped with a rebreather during a training exercise in Helford, England. The Office of Strategic Services worked closely with the British in planning highly dangerous missions in German-occupied France. Photo courtesy of Patrick K. O’Donnell from First SEALs: The Untold Story of the Forging of America’s Most Elite Unit.

“The explosion wiped out the bridges blocking all traffic for several days, and all of the Americans and Italians safely made it back to their base,” Patrick K. O’Donnell writes in his book First SEALs: The Untold Story of the Forging of America’s Most Elite Unit.

O’Donnell told Coffee or Die Magazine the electric surfboards used in the mission were more than just a wartime novelty. The surfboards (also referred to as inflatable mattresses and inflatable rafts) were among a series of groundbreaking technologies developed by the OSS MU in an era before swim fins, bubble-less rebreathers, and dive watches were accepted for military use.

“They had to do everything from scratch on a tiny budget,” O’Donnell told Coffee or Die. “The concept of the inflatable raft was used to assault enemy positions and allow them to get in close to penetrate behind enemy lines.”

The OSS MU’s surfboards were teardrop-shaped and received nicknames like “water lilies” and “flying mattresses.” The inflatable surfboards had silent, battery-powered motors and could hold either two OSS combat swimmers or up to 1,800 pounds of equipment, explosives, and ammunition. These surfboards had a cruising speed of 5 knots and a maximum range of 15 miles, but because of their low silhouettes in water, they served as one of the ideal methods for sneaking commandos into coastal areas.

As the war progressed, members of the OSS MU joined Underwater Demolition Team 10 in the Pacific theater.

“They were part of the Navy and conducted some of the great amphibious missions of the war,” O’Donnell said. “But it’s mostly geared towards preventing another Tarawa because of the issues of the landing craft not properly being able to get into the beach.”

Hank Weldon, a veteran of the OSS MU and member of UDT-10, participated in missions to clear ocean mines and beach obstacles before Marines would arrive for large-scale amphibious landings.

frogmen surfboards
“The OSS and Dr. Lambertsen not only developed a precursor to SCUBA (the LARU), they also created a variety of other diving and special operations gear for combat swimming, including a novel inflatable two-man surfboard with a silent, battery-operated motor that stealthily propelled teams to their targets.” Photo courtesy of Patrick K. O’Donnell from First SEALs: The Untold Story of the Forging of America’s Most Elite Unit.

“I let them in and left,” Weldon told the Valley Roadrunner newspaper in 2016. “I didn’t see a lot of action on the ground. I went in and cleared the areas for the ships. […] Opened the lanes for them. Took care of mines. Or eliminated markers that the Japanese were using as markers for their artillery.”

In order to swim through large quantities of explosives, Weldon and his swim buddies used surfboards.

“We called them paddleboards and used them to haul three hundred pounds of demolition,” Weldon said.

Frogmen surfboards proved to be extremely effective for the Allies during the hazardous maritime commando operations of World War II.

Read Next: One More Wave: The Navy SEALs Helping Disabled Veterans Heal With Custom Surfboards

Matt Fratus
Matt Fratus

Matt Fratus is a history staff writer for Coffee or Die. He prides himself on uncovering the most fascinating tales of history by sharing them through any means of engaging storytelling. He writes for his micro-blog @LateNightHistory on Instagram, where he shares the story behind the image. He is also the host of the Late Night History podcast. When not writing about history, Matt enjoys volunteering for One More Wave and rooting for Boston sports teams.

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