Burland, Brian A Fall from Aloft.

Twelve year old James Berkeley makes a terrifying midwinter journey across the Atlantic during the height of the German U-boat assault in 1942 aboard the fictitious Liberty ship EMPIRE UNITED. The book's strong suit is its unsentimental (indeed, unvarnished) depiction of British merchant seamen of that era along with vivid descriptions of the often hellish conditions in which they worked, particularly while on North Atlantic convoys.