To understand the Battle of the Atlantic, you need to go back one day before the actual armed conflict.
On July 14, 1942, a convoy of 19 merchant ships and five military escort ships set sail from Hampton Roads, Virginia. The convoy was named KS-520, with the “KS” indicating they were moving south along the coast heading to Key West, Florida.
At the same time, German U-boat 576 was operating off the North Carolina coast. However in an earlier engagement, the German submarine’s ballast tank was damaged by an aerial depth charge attack. The sub’s commander had radioed to U-boat headquarters in France that the damage was serious and he was going to return to Europe for repairs.
Historians believe the paths of the convoy and the sub intersected off the North Carolina coast. Despite the damage to the ballast tank, the commander found the convoy target too tempting to pass up.
On July 15, 1942, one of the convoy’s escorts picked up a sonar contact from the sub. It dropped depth charges but missed. Four torpedoes from U-576 ripped into the convoy. Two torpedoes hit the Chilore, one hit the J.A. Mowinckel and the fourth struck the Bluefields broadside, sinking her in minutes.
A few minutes later, U-576 suddenly surfaced in the middle of the convoy. Escort ships opened fire on the sub. Navy aircraft attacked with depth charges. The sub sank quickly, taking all 45 crewmembers with her.
The damaged ships headed towards shore to get help. However, in the confusion, they ran into what is called the Hatteras minefield: a collection of underwater mines strung along the coast to help protect from German U-boats. A tugboat sent out to help the ships hit a mine and sank. The Chilore hit a mine and sank in the mouth of the Chesapeake Bay as it was being towed. The J.A. Mowinckel also hit a mine but made it to drydock and was repaired and returned to service.
That's how the U.S. convoy and German U-boat crossed paths that fateful day, just off the coast of North Carolina. In all, four U.S. sailors were killed in the battle.
Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!