A wartime documentary, made under the auspices of the Crown Film Unit, made as a tribute to the Merchant Navy. During WWII they kept the lifeline to America and the Commonwealth open so that this little island could fight on. Even as late as 1943/4 when this was made the convoys still provided vital essential supplies as well as the materiel necessary to take the fight into Europe. This film dramatises the experiences of many merchant seamen.