During WWII, Italian frogmen successfully penetrated the harbor in Alexandria, Egypt riding manned torpedoes and damaging two Royal Navy battleships, HMS Valiant and HMS Queen Elizabeth, using nothing more than handheld devices called limpet mines. After, an impressed and worried Winston Churchill ordered a similar capability to be developed as soon as possible.

Unbeknownst to Mr. Churchill, the Italians’ unconventional attack resembled a plan proposed to the Admiralty months before by a British Royal Marine Captain named Herbert G. ‘Blondie’ Hasler. Unlike their Italian counterparts, however, the conventional-minded Admiralty quickly shot down Hasler’s idea as impractical. Another attempt with the more unconventional Combined Operation’s Headquarters also met with disapproval and was shelved, until that night on December 19, 1941 when those two battleships began slipping beneath the waves at their moorings. From that point on, Lord Louis Mountbatten, chief of Combined Operations, not only resurrected Hasler’s plan, he ordered a unit formed under his command, and the odd sounding Royal Marine Boom Patrol Detachment (RMBPD) came into being on July 6, 1942.

As far as leaders with unique specialties go, Hasler was the perfect man for the job. An experienced sea hand in the prewar years, he brought his knowledge of small boats to his new command at Southsea, Portsmouth, England where he began recruiting officers and men from the Royal Marine Small Arms School and Royal Marine Auxiliary battalion, respectively. He intended to take a hands-on approach and pass on his valuable knowledge to the men so that they would think and make decisions as he did.

This small group of men, just 34 in all, started developing tactics around the concept of using motorboats to penetrate Axis harbors. Again, this took its inspiration from the Italian frogmen and their triumphant raid against the Royal Navy at Souda Bay, Crete, on March 26, 1941 using the same technique. Minds quickly changed, though, after studying a second raid against British ships in Malta, which failed and resulted in several boats being captured. The time came to look at smaller craft.

Hasler modified his plans to use boats to penetrate the obstacles and canoes to carry out the final attacks. For this, he needed some modifications to the Special Boat Section’s folbot, which was redesigned to a more sturdy specification which enabled heavier loads to be carried, as well as being collapsible, unlike the standard design. These new canoes were built and given the codename Cockle.

Hasler put the new canoes to immediate use, leading his men on night practices in various rivers and harbors, where they learned to paddle silently over dozens of miles, creep up alongside ships and affix limpet mines, and just as quietly, scurry away to a rendezvous with only moonlight and, in some cases, their nerve guiding them.

It was needed, for soon Hasler joined in planning a mission for Combined Operations using everything they’d practiced. In the dossier containing the plan read everything that defined a classic Special Forces mission of the day. Surprise, swiftness and great expectations of what victory would bring, despite the long odds of it succeeding. In layman’s terms, it could almost be translated as a suicide mission, though no one dared mutter it.

The plan evolved from Hasler and others studying the background about how the Royal Navy and Air Force had tried to keep up steady pressure on German attempts to resupply the many French harbors facing the English Channel. Despite this, many merchant ships still made it round to the Bay of Biscay and into the main harbor at Bordeaux. Within the holds of these ships lay the raw goods and war material vital to Germany’s survival. If several of these ships could be damaged or sunk, it would put a significant dent in the German supply chain at least for a little while.