HMCS Guelph

The Flower-class corvette was a British class of 294 corvettes used during World War II by the Allied navies particularly as anti-submarine convoy escorts in the Battle of the Atlantic. Royal Navy ships of this class were named after flowers.

Sir Winston Leonard Spencer Churchill was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 during the Second World War, and again from 1951 to 1955. Apart from two years between 1922 and 1924, he was a Member of Parliament (MP) from 1900 to 1964 and represented a total of five constituencies. Ideologically an economic liberal and imperialist, he was for most of his career a member of the Conservative Party, which he led from 1940 to 1955. He was a member of the Liberal Party from 1904 to 1924.

Admiral Percy Walker Nelles, was a flag officer in the Royal Canadian Navy (RCN) and the Chief of the Naval Staff from 1 January 1934 to 15 January 1944. He oversaw the massive wartime expansion of the RCN and the transformation of Canada into a major player in the Battle of the Atlantic. During his tenure U-boats raided the Gulf of St. Lawrence, Canadian Northwest Atlantic command was created, and the RCN provided up to 40% of all escort forces in the North Atlantic. His handling of the RCN's war effort had its opponents however, and he was removed from his post as Chief of the Naval Staff in January 1944. He was sent to London as Overseas Naval Attaché, coordinating RCN operations for Operation Overlord. He retired in January 1945 as a full admiral.

The Hedgehog was a forward-throwing anti-submarine weapon that was used primarily during the Second World War. The device, which was developed by the Royal Navy, fired up to 24 spigot mortars ahead of a ship when attacking a U-boat. It was deployed on convoy escort warships such as destroyers and corvettes to supplement the depth charges.

Collingwood is a town in Simcoe County, Ontario, Canada. It is situated on Nottawasaga Bay at the southern point of Georgian Bay. Collingwood is well known as a tourist destination, for its skiing in the winter, and limestone caves along the Niagara Escarpment in the summer.

Toronto is the capital city of the Canadian province of Ontario. With a recorded population of 2,794,356 in 2021, it is the most populous city in Canada and the fourth most populous city in North America. The city is the anchor of the Golden Horseshoe, an urban agglomeration of 9,765,188 people surrounding the western end of Lake Ontario, while the Greater Toronto Area proper had a 2021 population of 6,712,341. Toronto is an international centre of business, finance, arts, sports and culture, and is recognized as one of the most multicultural and cosmopolitan cities in the world.

Halifax is the capital and largest municipality of the Canadian province of Nova Scotia, and the largest municipality in Atlantic Canada. Halifax is one of Canada's fastest growing municipalities, and as of 2022, it is estimated that the CMA population of Halifax was 480,582, with 348,634 people in its urban area. The regional municipality consists of four former municipalities that were amalgamated in 1996: Halifax, Dartmouth, Bedford, and Halifax County.

The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against France. The modern Royal Navy traces its origins to the early 16th century; the oldest of the UK's armed services, it is consequently known as the Senior Service.

USS S-21 (SS-126) was a first-group S-class submarine of the United States Navy in commission from 1921 to 1922 and from 1923 to 1942. In 1928, she made the first gravimetric measurements ever made aboard a U.S. ship at sea. Prior to World War II, she operated in the Atlantic Ocean, Caribbean Sea, and Pacific Ocean, and after the United States entered the war, she operated off Panama. She then served in the Royal Navy as HMS P.553 from 1942 to 1944.

USS S-22 (SS-127) was a first-group S-class submarine of the United States Navy in commission from 1924 to 1942. Prior to World War II, she operated in the Atlantic Ocean, Caribbean Sea, and Pacific Ocean, and after the United States entered the war, she operated off Panama. She then served in the Royal Navy as HMS P.554 from 1942 to 1944.

Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania and the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. It is one of the most historically significant cities in the United States and served as the nation's capital until 1800. Philadelphia is the nation's sixth-largest city with a population of 1,603,797 as of the 2020 census. Since 1854, the city has been coextensive with Philadelphia County, the most populous county in Pennsylvania and the urban core of the Delaware Valley, the nation's seventh-largest and one of the world's largest metropolitan regions with 6.245 million residents. Philadelphia is known for its extensive contributions to American history, especially the American Revolution, and for its contemporary influence in business and industry, culture, sports, and music.

The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of its active battle fleet alone exceeding the next 13 navies combined, including 11 allies or partner nations of the United States as of 2015. It has the highest combined battle fleet tonnage and the world's largest aircraft carrier fleet, with eleven in service, two new carriers under construction, and five other carriers planned. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the United States Navy is the third largest of the United States military service branches in terms of personnel. It has 290 deployable combat vessels and more than 2,623 operational aircraft as of June 2019.

Western Local Escort Force (WLEF) referred to the organization of anti-submarine escorts for World War II trade convoys from North American port cities to the Western Ocean Meeting Point near Newfoundland where ships of the Mid-Ocean Escort Force (MOEF) assumed responsibility for safely delivering the convoys to the British Isles.

Mid-Ocean Escort Force (MOEF) referred to the organisation of anti-submarine escorts for World War II trade convoys between Canada and Newfoundland, and the British Isles. The allocation of United States, British, and Canadian escorts to these convoys reflected preferences of the United States upon their declaration of war, and the organisation persisted through the winter of 1942–43 despite withdrawal of United States ships from the escort groups. By the summer of 1943, United States Atlantic escorts were focused on the faster CU convoys and the UG convoys between Chesapeake Bay and the Mediterranean Sea; and only British and Canadian escorts remained on the HX, SC and ON convoys.

Panama, officially the Republic of Panama, is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Costa Rica to the west, Colombia to the southeast, the Caribbean Sea to the north, and the Pacific Ocean to the south. Its capital and largest city is Panama City, whose metropolitan area is home to nearly half the country's 4 million people.

Lloyd's Register Group Limited (LR) is a technical and professional services organisation and a maritime classification society, wholly owned by the Lloyd’s Register Foundation, a UK charity dedicated to research and education in science and engineering. The organisation dates to 1760. Its stated aims are to enhance the safety of life, property, and the environment, by helping its clients to improve the safety and performance of complex projects, supply chains and critical infrastructure.