The Website for Merchant Ships during WW2.

Arnold Hague Ports Database Search over 1,000,000 port entries to chart a ship's movements.
  Arnold Hague Convoy Database Search 28,156 convoys (366,192 ship movements).
  Arnold Hague Shorter Series An additional 9,610 convoys (57,504 ship movements).
  OS and OS/KMS Convoys
 UK to Freetown, Sierra Leone and Gibraltar, 1941-1945.
  SL and SL/MKS Convoys Freetown, Sierra Leone and Gibraltar to UK, 1939 - 1945.
  Russian Convoys 78 Russian convoys 1941 - 1945 (mercantile and naval vessels).
  OA OB OG Convoys UK ports to the Atlantic and Gibraltar 1939-1941.
  WS Convoys Troop and Military Supply convoys 1940 - 1943.
  Convoy OS.33 A detailed study of convoy OS.33
  Multi-Convoy Web Search Search across the Web for a particular merchant ship.
  Convoy Finder Find convoys by the date that they sailed or arrived or by their convoy code.
  Extras Convoy charts, sunrise/ sunset times 1939-45, calendar 1939-45, distance calculator, convoy codes, convoy signals, Ebook, Merchant Shipping Movement Cards, U-boat charts.
  Updates/ Announce Last update July 8, 2008.
You are invited to contribute any extra information for inclusion on this site.