In July of 1942 the German U-Boat 215, Commanded by Kptlt. Frtiz Hoekner, was on the secret mission to North America. U-215 was a very rare class of u-boat, a type VIID. In total there was only 6 of this type of vessel built. The uniqueness of this design was in the addition of a thirty-two foot compartment between the control room and the galley that housed five vertical mine tubes. Each tube held five SMA (magnetic influence) mines. The addition of these mine tubes allowed the U-Boat Command to assign dual purpose missions to these boats, that of mining enemy harbors and anchorages and the traditional attack role of torpedoing enemy shipping. Kptlt. Hoekner's secret mission was to mine the entrance of Boston Harbor and create havoc as convoys started their long journey across the Atlantic. He would never accomplish this task. The torpedo he sent into the hull of the Liberty Ship USS "Alexander Macomb” would seal his fate and the fate of his crew long before he reached his destination. The "Alexander Macomb” was built in Baltimore, Maryland. She was launched on May 6th, 1942. On July 3rd of that year, she was lagging behind her convoy in dense fog. She was six miles back when U-215 fired her torpedoes. Thirty men of her sixty-man crew were killed or wounded in the blast. She sank minutes after the secondary explosions in her cargo hold opened her hull to the waters of the cold North Atlantic. Minutes after the torpedoes hit the "Macomb,” the convoy escort vessel "Le Tiger” took up the chase for the U-boat. Using ASDEC (a primitive form of sonar) they located the sub as she ran for deeper water. Dropping depth charges at close intervals the "Le Tiger” first slowed her target, then the pings from the ASDEC indicated the target had come to a complete stop on the bottom. Oil and debris on the surface indicated a kill. The "Le Tiger” then went to the aid of the "Macomb” survivors. Using targets provided by fishermen and multi-beam charting done by the Bedford Institute of Oceanography, the "Sea Hunters” will search for and dive these wrecks, confirming the kill of the U-215, and telling the story of the loss of the "Macomb” and the Nazi plans to mine Boston Harbor.