page_title: Flower-class corvette
section_title: Design
hierarchical_section_title: Flower-class corvette / Design
caption_attribution_description: Officers on the bridge of Canadian Flower class corvette HMCS Trillium.
context_page_description: The Flower-class corvette was a British class of 294 corvettes used during World War II, specifically with the Allied navies as anti-submarine convoy escorts during the Battle of the Atlantic. Royal Navy ships of this class were named after flowers, hence the name of the class.
  The majority served during World War II with the Royal Navy and Royal Canadian Navy. Several ships built largely in Canada were transferred from the RN to the United States Navy under the lend-lease programme, seeing service in both navies. Some corvettes transferred to the USN were manned by the US Coast Guard. The vessels serving with the US Navy were known as Temptress and Action-class patrol gunboats. Other Flower-class corvettes served with the Free French Naval Forces, the Royal Netherlands Navy, the Royal Norwegian Navy, the Royal Indian Navy, the Royal Hellenic Navy, the Royal New Zealand Navy, the Royal Yugoslav Navy, and, immediately post-war, the South African Navy.
  After World War II many surplus Flower-class vessels saw worldwide use in other navies, as well as civilian use. HMCS Sackville is the only member of the class to be preserved as a museum ship.
context_section_description: In early 1939, with the risk of war with Nazi Germany increasing, it was clear to the Royal Navy that it needed more escort ships to counter the threat from Kriegsmarine U-boats. One particular concern was the need to protect shipping off the east coast of Britain. What was needed was something larger and faster than trawlers, but still cheap enough to be built in large numbers, preferably at small merchant shipyards, as larger yards were already busy. To meet this requirement, the Smiths Dock Company of Middlesbrough, a specialist in the design and build of fishing vessels, offered a development of its 700-ton, 16 knots (18 mph; 30 km/h) whale catcher Southern Pride. They were intended as small convoy escort ships that could be produced quickly and cheaply in large numbers. Despite naval planners' intentions that they be deployed for coastal convoys, their long range meant that they became the mainstay of Mid-Ocean Escort Force convoy protection during the first half of the war.
  The Flower class became an essential resource for North Atlantic convoy protection until larger vessels such as destroyer escorts and frigates could be produced in sufficient quantities. The simple design of the Flower class using parts and techniques (scantlings) common to merchant shipping meant they could be constructed in small commercial shipyards all over the United Kingdom and Canada, where larger (or more sophisticated) warships could not be built. Additionally, the use of commercial triple expansion machinery instead of steam turbines meant the largely Royal Naval Reserve and Royal Naval Volunteer Reserve crews that were manning the corvettes would be familiar with their operation.
  Flower-class vessels were slow for a warship, with maximum speed of 16 kn (30 km/h). They were also very lightly armed as they were intended solely for anti-submarine warfare; many of the RCN's original Flower-class ships were initially fitted with minesweeping equipment, while virtually all of the modified Flowers were fitted with a limited anti-aircraft capability.
  The original Flowers had the standard RN layout, consisting of a raised forecastle, a well deck, then the bridge or wheelhouse, and a continuous deck running aft. The crew quarters were in the foc'sle while the galley was at the rear, making for poor messing arrangements.
  The modified Flowers saw the forecastle extended aft past the bridge to the aft end of the funnel, a variation known as the "long forecastle" design. Apart from providing a very useful space where the whole crew could gather out of the weather, the added weight improved the ships' stability and speed and was retroactively applied to a number of the original Flower-class vessels during the mid and latter years of the war.
  The original Flowers had a mast located immediately forward the bridge, a notable exception to naval practice at that time. The modified Flowers saw the mast returned to the normal position immediately aft of the bridge; however, this does not seem to have been done in all of the modified builds or conversions of the original vessels.
  A cruiser stern finished the appearance for all vessels in the class.
caption: Officers on the open bridge of HMCS Trillium
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