The ship was Dutch. Presumably so were the six crew who died.
TRITON
Koninklijke Nederlandsche Stoomb. Maats.; 1928; A.G.Neptun;
2,078 tons; 285-7x44-7x17-7; 155 n.h.p.; triple-expansion
engines.
The Dutch steamship Triton was torpedoed, shelled and sunk by
the German submarine U-558 on June 1st, 1942, on a voyage from
Demerara to Chesapeake Bay for orders. Six of the crew were lost.
http://www.photoship.co.uk/Disaster%20Chest/716.pdf
http://www.ubootwaffe.net/ops/boat.cgi
Remarkably, I can even tell you the names of the six crewmen who died:
M. Elmont
N.J. v. Eijck
J. de Graaf
D. v. Leeuwarden
J.F.J. Lendorff
J. da Silva
They all look Dutch except for the last one, which looks like it could be South American. The ship was sailing from Demerara (Guyana).
http://www.whawessels-knsmboek.nl/images/lijst1.pdf