Official immigration to Palestine was limited by the very small number of immigration certificates allocated to emigrants from the Protectorate. As in the case of other countries in the free world, the British administration of the Palestinian territories refused to accept Jewish refugees.
Unlike other countries, however, Palestine was regarded from 1917 onwards as the place where a Jewish national homeland, a state of national Jews, would be established. Exodus to the place to which generations have turned in prayer several times a day was thus not just any illegal migration - it was the fulfillment of an ancient dream of returning home. And so, in parallel with the futile efforts at legal emigration, Zionist resistance organizations organized illegal groups of emigrants bound for Palestine. Their efforts were then copied by various businessmen and hucksters reselling places on illegal boats at large markups.
Until the summer of 1941, the Nazi authorities encouraged Jewish emigration from Europe; after all, one of their slogans was "Jews to Palestine!" Even after the start of the war, the Danube River was legally considered international waters, and from the Danube Delta, the way to the Mediterranean was open to ships with enough cash for bribes.
Now take a look at the recollection of Karel Hajek, whom you met at the beginning of this IWalk.
Why did the British army fire on a crumbling boat packed with refugees?