Upon arrival in Halifax, "Emerald" was assigned to North Atlantic convoy escort duty for the return voyage. The large convoy was filled with American munitions for the war effort. Since the "Emerald" had been designed and equipped for work in gentler climates this was very uncomfortable as well as dangerous duty. The Canadian Red Cross provided a large supply of warm gloves, woolen scarves, sea boot stockings, leather headgear lined with wool and fur, and woolen underwear, for the crew were ill-equipped to face winter storms with their tropical gear. The convoy lost two merchant ships to U-boats on the trip to the United Kingdom.