At that time the Halifax Harbour is considered to be one of the safest harbours in the world. Reaching far inland from the Atlantic Ocean it is protected not only from the fierce ocean but also, and most important in times of war (check back the date), from the sneaky marauding German U-boats. But war is mostly a good business and the war effort included the shipping of large amounts of material to Europe. Because of its strategic location in North America, Halifax became the staging point for many trans-Atlantic convoys.
One ship which arrived in Halifax Harbour that day was the Mont Blanc. The vessel arrived too late from New York the day before and could not enter the harbour on December 5th due to harbour regulations and because a large chain was raised across the mouth of the harbour to keep out U-boats. Those who arrive too late watch the safest harbour in the world from the outside and are left to themselves for a cosy night with the Germans. Anchor is raised on the Mont Blanc at 07:30 on December 6th to enter the harbour.
At the same time as the Mont Blanc sailed in, a second ship, the Imo, prepared to leave port and was heading to the open ocean. So far, so good...