Starting in 1939 , a clandestine immigration effort called Aliya Bet was spearheaded by an organisation called Mossad LeAliyah Bet . Tens of thousands of European Jews escaped the Nazis in boats and small ships headed for Palestine . The Royal Navy intercepted many of the vessels ; others were unseaworthy and were wrecked ; a Haganah bomb sunk the , killing 267 people ; two more were sunk by Soviet submarines . The motor schooner was torpedoed and sunk in the Black Sea by a Soviet submarine in February 1942 with the loss of nearly 800 lives . The last refugee boats to try to reach Palestine during the war were the '' Bulbul '' , and '' Morina '' in August 1944 . A Soviet submarine sank the motor schooner '' Mefküre '' by torpedo and shellfire and machine-gunned survivors in the water , killing between 300 and 400 refugees . Illegal immigration resumed after World War II
torpedoed and sunk
Struma disaster
Mandatory Palestine