From the outbreak of war in 1914 to the creation of the Mercantile Marine Reserve and the eventual introduction of convoys in 1917, this book charts the experiences, contribution and sacrifices made by merchant mariners from Wales. During the First World War, merchant crew faced the dangers of mines, U-boats and commerce raiders in the course of moving the goods, men and materials that were vital for victory. The outcomes of such encounters are examined within a broader context of the diversity of vessels, trades and prevailing working conditions. This study also includes important new insights into the participation of both women and minority-group seafarers in the mercantile marine. Using a wide range of evidence drawn from contemporary newspaper reports, ships’ crew agreements and official papers, the multi-faceted world of civilian mariners caught up in the war at sea is revealed.