Most of 1939's Australian merchant fleets and their management had lived through the Great War of 1914-1919. So when the prime ministers of the times - Robert Menzies in 1939 and John Curtin in 1941 - announced that Australia was at war, respectively with Germany and then Japan, it would have been no surprise that the country's Merchant Navy stood ready to contribute to the Allied cause as well as its own safeguarding.

Indeed those building new tonnage in the United Kingdom shipyards in the late 1930s and early 1940s were not insensitive to looming world events.

So the twenty ship-owning companies 'stepped-up' and so did their mariners. But these were not easy times for seafarers; they were not 'sworn' members of Australia's armed forces, as often as not they sailed dangerous waters without naval escort, they were engaged, 'signed-on', usually on a voyage-by-voyage basis, they were not put into uniform, their pay stopped (at least in the early part of the war) if and when their ship was sunk, and they risked imprisonment if they refused to sail when a ship's job was available. While in certain operational areas they were paid a War Risk Bonus which marginally supplemented their modest rates of pay.

But they served and sacrificed, and sharing their service, often their hardships and their watery risks and losses in their defensively-equipped merchant ships were the Royal Australian Navy's 'D.E.M.S.gunners', tasked to serve the small-calibre guns usually mounted at bow and stern.

They were part of how the Allied cause won the Second World War.