Approaches to Virginia Capes Mined in 1942: What Did the Swiss Know? And When Did They Know It?

Four tugs gently push the tanker Robert S. Tuttle
 after the ship struck a mine off of False Cape. 
The tugs took the tanker to Baltimore for
 repairs. She survived the war.

In June 1942, the Kreigsmarine began to wrap up Operation Paukenschlag,  the U-boat offensive on the American eastern seaboard. As U-boats started to sail east, U-701 left behind a going away present: a minefield near the entrance to the Chesapeake Bay. 

A thirteen ship convoy labeled KN-109 (Key West to Norfolk) steamed into the minefield, shortly after U-701 finished laying the mines. Escorted by the Norfolk-based destroyer USS Bainbridge (DD-246) and the armed fishing trawler HMT Kingston Ceylonite, the convoy switched from a double column formation to a single file formation as it sailed off the coast of False Cape.  Shortly after the switch, one of the tankers in the convoy, SS Robert S. Tuttle, struck a mine on the starboard, forward section of the ship.  Thirty minutes later, Esso Augsta also struck a mine.  During the confusion, Kingston Ceylonite turned to help, only to hit three mines in a row, completely obliterating the trawler. The explosions killed seventeen of her thirty-three man crew.

Thinking a U-boat was in the area, Bainbridge turned to counter-attack and dropped eight depth charges. While there was no submarine the area, the depth charges set off nine mines.  Despite sweeping the area by other ships out of Hampton Roads, the minefield continued to cause further damage well into September. 

Fifth Naval District Map of the mine attacks on convoy KN-109 and other ships.

U.S. Navy intelligence suspected that neutral-flagged, but pro-Axis, merchant vessels were laying mines on behalf of the Germans.  Intelligence officers from the Fifth Naval District (headquartered at Naval Station Norfolk) boarded three ships: the Greek-flagged tanker Helena Kulakunds, the Spanish-flagged freighter Monto Mulhacen, and the Swiss-flagged freighter Calanda.  The officers found no evidence of mines or mine laying equipment.  However, they did find the ships' sailing instructions and noticed they were very different than those of Allied-flagged merchant ships.  Specifically, the instructions informed the ships not to sail in the waters off of Virginia Beach and False Cape.  The officers discovered that the instructions came from the Swiss Embassy in Portugal.

Fifth Naval District Intelligence Office map-The solid line is the path followed by west bound
Allied ships, which took them straight into the minefield. The neutral ships, however, followed the
dotted line, which took them north of the minefield.

The Fifth Naval District Intelligence Office concluded that the freighters and the embassy were tipped off by German or Italian officials. It wrote, "It is most unusual, that a neutral nation, supposedly with no first-hand information of the approaches to a belligerent harbor, would undertake to issue routing instructions for the entrance in direct contravention to the instructions issued by nations charged with keeping a channel into such harbor open and free of mines."