In December 1942, the HMS Tuna, a submarine serving with the Royal Navy launched in the middle of a cold night into the North Atlantic. It crept its way through the Continental shelf under the Bay of Biscayne. Six canoes, each with two special forces soldiers, it was a Royal Task Force – the brainchild of Winston Churchill himself and its moniker was Special Operations Executive or SOE. It was a reaction to the war turning south for the United Kingdom. Churchill had just watched as his Army was cornered in Dunkirk and had to be evacuated. He just saw his cities burn every night in the aftermath of the Blitzkrieg and the V-1 rockets. The nation was questioning whether it made sense that the Prime Minister also be the Minister of Defense, and perhaps he should vacate that seat. But Churchill fought back as only he could: by hook or by crook. This time these specially trained aquatic warriors were paddling into the night, threading their way in an exhausting, four day journey that would have them lay up and hide by day and move by night. The groups Britain formed at the end of 1942 often an into each other performing the same mission
The Twelve men would have to move through machine gun posts, dozens of armed German torpedo boats, marine artillery emplacements, submarine patrols, and mines. It was a suicide mission from day one. The Bay of Biscayne was in German occupied France and the Bay itself was being used as a safe haven and launching point for German and Italian Submarine forces. So this was the logical place for a floundering empire to strike back. The leader, Blondie Hasler had impressed Lord Mountbatten and was given the funding needed to carry off the plan.
The Plan was to plant limpet minds on cargo vessels in the harbor and slow reinforcements. Of course another strike force was actually active in the same bay and had targeted the same ships that the SOE group had targeted. The SOE group, also called the Baker Street Irregulars and the Ministry of Ungentlemanly Warfare, was there to bring the fight right to the Nazis in their own backyard.
The actual mission launched on December 7th1942, ended with the tragic loss of most of the team and questionable effects and benefits of the sapper operation. The first team was excluded from the mission due to a leakey boat. Two of the teams were taken under by rip tides, and three other teams were captured and executed. The last two kayaks split up and hit different groups of ships in the process of loading. The limpet mines went off one after and another and the delay gave Hasler a chance to make good his escape over land into German occupied France and into Gibraltar. When his strike teams made it to their targets in port, they were totally undetected and unbelievably lucky that all these German and Italian guards were sleeping. Of the 12 who began, only Hasler and his partner made it through after sinking the Tannenburg and two other cargo haulers in shallow waters.
The odd thing about it was that if they had chosen less security internally and talked to each other, the two British insurgent teams might have lowered the hammer on the Germans in a really big way. A classic example of the right hand not knowing where the left hand was.
Source: Blondie: A Biography of Lieutenant Colonel HG Hasler Dso, obe, Croix De Guerre, Royal Marines by Ewen Southby-Tailyour (February 1998), Wiki
Magnetic Limpet Mine