U-751 Bigalk 3-May-1942 5 days
Given that schooners at the time (as we shall see with the Vivian P. Smith, Wawaloam, Cheerio, Sande, James E. Newsom and Helen Forsey) were rarely equipped with radio equipment, this conspiracy theory can be discounted as baseless.
On the 19th of May Bigalk dispatched the 3,110-ton American freighter Isabela of Point Gravois, the southwestern tip of Haiti, for a total patrol tonnage of 4,555 GRT. After ten days in the Caribbean proper U-751 exited the region via the Anegada Passage on the night of the 28th and 29th of May and began the trans-Atlantic voyage back to France.
SOURCES: Gudmundur Helgason, Rainer Kolbicz, www.uboat.net, 2013, Kenneth Wynn, U-boat Operations of the Second World War, Volume 1 and Volume 2, 1997, R. Busch, and H.-J. Röll, German U-boat Commanders of World War II, 1988, Franz Kurowski, Knights Cross Holders of the U-boat Service, Otto Giese, Shooting the War: The Memoir and Photographs of a U-Boat Officer in World War II, 1994