The Porte-class gate vessels were a class of five boom defence vessels built in the early 1950s and operated by the Royal Canadian Navy (RCN) and Canadian Forces (CF) during the Cold War. The class derived its name from the gates of the French fortifications of Québec and Louisbourg and was designed by the RCN as a replacement for World War I-era Battle-class trawlers used to operate anti-submarine booms during World War II. The Porte class were used primarily as training vessels during the Cold War.

Quick Facts Class overview, General characteristics ...

Class overview
Name	Porte class
Operators	Royal Canadian Navy ⁄ Canadian Maritime Command
Preceded by	Battle class
In commission	5 December 1951 – 19 December 1996
Completed	5
Scrapped	5
General characteristics
Type	Boom defence vessel
Displacement	429 tons
Length	125 ft 6 in (38.3 m)
Beam	26 ft 4 in (8.0 m)
Draught	13 ft (4.0 m)
Propulsion	1 diesel engine, 1 shaft 600 bhp (450 kW)
Speed	11 kn (20 km/h)
Complement	originally 3 officers, 20 ratings; later expanded to 5 officers, 3 officers under training, 30 ratings
Sensors and processing systems	Mechanical minesweeping equipment (later removed) Boom defence equipment
Armament	1 × 40 mm Bofors single mount (later removed)

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The Porte class were designed with the possibility of commercial adoption of the design by the Canadian fishing industry. The gate vessels were planned for use as auxiliary vessels during peacetime.^[1] The Porte class was of a trawler design, and were designed to operate the anti-submarine booms for harbour defence. They were also capable of being fitted for minelaying.^[2]

The Porte class were 125 feet 6 inches (38.3 m) long with a beam of 26 feet 4 inches (8.0 m) and a draught of 13 feet 0 inches (4.0 m). They displaced 429 long tons (436 t) fully loaded and had an initial complement of 3 officers and 20 ratings.^[2][3] The Porte class were powered one Fairbanks-Morse 6-cylinder diesel engine driving one shaft creating 600 brake horsepower (450 kW). This gave the vessels a maximum speed of 11 knots (20 km/h; 13 mph).^[2][4] The vessels had a range of 4,000 nautical miles (7,400 km; 4,600 mi) at 10 knots (19 km/h; 12 mph). They were equipped with one Racal Decca navigation radar operating on the I band.^[4] The ships were armed with one 40 mm gun placed forward.^[5]

The first Porte-class vessel was ordered September 1949.^[1] Porte Saint Jean and Porte Saint Louis were based at Halifax, Nova Scotia and Porte Dauphine, Porte Québec and Porte de la Reine at Esquimalt, British Columbia. From 1958 to 1974, Porte Dauphine was loaned to the Department of Transport (DOT) as an environmental research ship on the Great Lakes, before transferring to the West Coast via the Panama Canal.^[3][8] Porte Dauphine was modified for DOT use, which involved the installation of a widened wheelhouse and a cafeteria.^[9] The vessels were used to train naval reserve crews in key trades such as navigation, diesel mechanics, communications and logistics.^[4][5] Porte Saint Jean and Porte Saint Louis began training on the Great Lakes in 1953, working with HMCS Star in Hamilton, Ontario. They sometimes travelled to Bermuda for training.^[10] In 1973, Porte Saint Jean and Porte Saint Louis sailed into the eastern Arctic.^[11] With the arrival of the Kingston-class coastal defence vessels in the mid-1990s, the Porte class was retired. Porte Dauphine was the first, discarded in December 1995, followed by Porte Saint Jean and Porte Saint Louis in March 1996 and Porte Québec and Porte de la Reine in December 1996.^[12]