HMCS Bayfield

The Halcyon class was a class of 21 oil-fired minesweepers built for the British Royal Navy between 1933 and 1939. They were given traditional small ship names used historically by the Royal Navy and served during World War II.

The Fundy-class minesweepers were a class of four minesweepers operated by the Royal Canadian Navy during the Second World War. All four ships entered service in 1938 and the class were discarded in 1945, sold for mercantile service. Three ended up sold to Chinese interests, while one remained active in Canada until 1987.

The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is called a compression-ignition engine. This contrasts with engines using spark plug-ignition of the air-fuel mixture, such as a petrol engine or a gas engine.

Length overall is the maximum length of a vessel's hull measured parallel to the waterline. This length is important while docking the ship. It is the most commonly used way of expressing the size of a ship, and is also used for calculating the cost of a marina berth.

The beam of a ship is its width at its widest point. The maximum beam (BMAX) is the distance between planes passing through the outer extremities of the ship, beam of the hull (BH) only includes permanently fixed parts of the hull, and beam at waterline (BWL) is the maximum width where the hull intersects the surface of the water.

The draft or draught of a ship's hull is the vertical distance between the waterline and the bottom of the hull (keel). The draught of the vessel is the maximum depth of any part of the vessel, including appendages such as rudders, propellers and drop keels if deployed. Draft determines the minimum depth of water a ship or boat can safely navigate. The related term air draft is the maximum height of any part of the vessel above the water.

The displacement or displacement tonnage of a ship is its weight. As the term indicates, it is measured indirectly, using Archimedes' principle, by first calculating the volume of water displaced by the ship, then converting that value into weight. Traditionally, various measurement rules have been in use, giving various measures in long tons. Today, tonnes are more commonly used.

The knot is a unit of speed equal to one nautical mile per hour, exactly 1.852 km/h. The ISO standard symbol for the knot is kn. The same symbol is preferred by the Institute of Electrical and Electronics Engineers (IEEE), while kt is also common, especially in aviation, where it is the form recommended by the International Civil Aviation Organization (ICAO). The knot is a non-SI unit. The knot is used in meteorology, and in maritime and air navigation. A vessel travelling at 1 knot along a meridian travels approximately one minute of geographic latitude in one hour.

Fuel oil is any of various fractions obtained from the distillation of petroleum. Such oils include distillates and residues. Fuel oils include heavy fuel oil, marine fuel oil (MFO), bunker fuel, furnace oil (FO), gas oil (gasoil), heating oils, diesel fuel and others.

The QF 12-pounder 12-cwt gun (Quick-Firing) was a common, versatile 3-inch (76.2 mm) calibre naval gun introduced in 1894 and used until the middle of the 20th century. It was produced by Armstrong Whitworth, Elswick and used on Royal Navy warships, exported to allied countries, and used for land service. In British service "12-pounder" was the rounded value of the projectile weight, and "12 cwt (hundredweight)" was the weight of the barrel and breech, to differentiate it from other "12-pounder" guns.

The Oerlikon 20 mm cannon is a series of autocannons, based on an original German Becker Type M2 20 mm cannon design that appeared very early in World War I. It was widely produced by Oerlikon Contraves and others, with various models employed by both Allied and Axis forces during World War II. Many versions of the cannon are still used today.

A depth charge is an anti-submarine warfare (ASW) weapon. It is intended to destroy a submarine by being dropped into the water nearby and detonating, subjecting the target to a powerful and destructive hydraulic shock. Most depth charges use high explosive charges and a fuze set to detonate the charge, typically at a specific depth. Depth charges can be dropped by ships, patrol aircraft, and helicopters.

The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. The laying of the keel is often the initial step in the construction of a ship. In the British and American shipbuilding traditions, this event marks the beginning date of a ships construction.

The City of North Vancouver is a city on the north shore of Burrard Inlet, British Columbia, Canada. It is the smallest in area and the most urbanized of the North Shore municipalities. Although it has significant industry of its own – including shipping, chemical production, and film production – the city is considered to be a suburb of Vancouver. The city is served by the Royal Canadian Mounted Police, British Columbia Ambulance Service, and the North Vancouver City Fire Department.

British Columbia, commonly abbreviated as BC, is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, forests, lakes, mountains, inland deserts and grassy plains, and borders the province of Alberta to the east, the territories of Yukon and Northwest Territories to the north, and the US states of Washington, Idaho and Montana to the south and Alaska to the northwest. With an estimated population of 5.3 million as of 2022, it is Canada's third-most populous province. The capital of British Columbia is Victoria and its largest city is Vancouver. Vancouver is the third-largest metropolitan area in Canada; the 2021 census recorded 2.6 million people in Metro Vancouver.

Nova Scotia is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. Nova Scotia is Latin for "New Scotland".

A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support and can help maintain cohesion within a unit. It may also be used in a non-military sense, for example when driving through remote areas.

The attack on Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service upon the United States against the U.S. naval base at Pearl Harbor in Honolulu, Territory of Hawaii, just before 8:00 a.m. on Sunday, December 7, 1941. The United States was a neutral country at the time; the attack led to its formal entry into World War II the next day. The Japanese military leadership referred to the attack as the Hawaii Operation and Operation AI, and as Operation Z during its planning.

Prince Rupert is a port city in the province of British Columbia, Canada. Its location is on Kaien Island near the Alaskan panhandle. It is the land, air, and water transportation hub of British Columbia's North Coast, and has a population of 12,220 people as of 2016.

Atlantic Canada, also called the Atlantic provinces, is the region of Eastern Canada comprising the provinces located on the Atlantic coast, excluding Quebec. The four provinces are New Brunswick, Newfoundland and Labrador, Nova Scotia, and Prince Edward Island. As of 2021, the landmass of the four Atlantic provinces was approximately 488,000 km2, and had a population of over 2.4 million people. The provinces combined had an approximate GDP of $121.888 billion in 2011. The term Atlantic Canada was popularized following the admission of Newfoundland as a Canadian province in 1949.

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.

Baltimore is the most populous city in the U.S. state of Maryland, the fourth most populous city in the Mid-Atlantic, and the 30th most populous city in the United States with a estimated population of 595,218 in 2023. Baltimore was designated an independent city by the Constitution of Maryland in 1851, and today it is the most populous independent city in the nation. As of 2023, the population of the Baltimore metropolitan area was estimated to be 2,921,051, making it the nation's 20th largest metropolitan area. Baltimore is located about 40 miles (64 km) north northeast of Washington, D.C., making it a principal city in the Washington–Baltimore combined statistical area (CSA), the third-largest CSA in the nation, with a 2023 estimated population of 10,042,122.

Maryland is a state in the Mid-Atlantic region of the United States. It borders Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to its east. With a total land area of 12,407 square miles (32,130 km2), Maryland is the 8th smallest state by land area, but with a population of over 6,177,200, it ranks as the 18th most populous state and the 5th most densely populated. Baltimore is the largest city in the state, and the capital is Annapolis. Among its occasional nicknames are Old Line State, the Free State, and the Chesapeake Bay State. It is named after Henrietta Maria, the French-born queen of England, Scotland, and Ireland, who was known then in England as Mary.