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Naval Warfare

Flower (class)

Corvette Warship / Minesweeper / Patrol Vessel [ 1939 ]

The Flower-class corvette warships of British design were critical to victory in the Battle of the Atlantic and elsewhere during the fighting of World War 2.

Authored By: Staff Writer | Last Edited: 08/24/2017 | Content ©www.MilitaryFactory.com | The following text is exclusive to this site.

The corvette warship was reintroduced to the British Royal Navy (RN) just prior to World War 2 (1939-1945) with the adoption of the Flower-class surface ships. This collection of warships, whose hull design was derived a commercial whaling vessel, was developed around the concept of minesweeping and coastal area escort. During the conflict, the group was pressed into deep water service and played a critical role for many operators - particularly for the British during the "Battle of the Atlantic" (September 1939 - May 1945).

The Flower-class was also known as the Gladiolus-class, primarily because of the lead ship of the group, HMS Gladiolus. All of the British ships were named after flowers which is how the class name came to be. Gladiolus was laid down by Smiths Dock Company at South Bank-on-Tees on October 19th, 1939 and launched on January 24th, 1940. She was formally commissioned on April 6th, 1940 but sunk on October 17th, 1941.©MilitaryFactory.com
Two-hundred twenty-five of the class were originally planned and two distinct batches ultimately emerged, "Flower-class" and "Modified Flower-class". About eleven of the ships were cancelled and, during the war, some thirty-three were lost in action and twenty-two of these to enemy submarines alone - such was the treacherous nature of naval warfare in the unpredictable Atlantic.

The Flower-class was a ship not truly designed for deep water work despite their hull design origins in a whaling vessel but a shortage of such warships for the RN, and the growing threat of German ships and submarines across the Atlantic, ensured that these compact platforms would be pushed to their limits. The group is known to have performed rather poorly in choppy seas but their machinery was easy to mass produce and maintain/repair which made them good wartime investments. In service, the ships were utilitarian corvettes called to handle many different types of sorties.

The Flower-class displaced some 1,035 tons (short). Length was 205 feet with a beam of 33 feet and a draught of 11.5 feet - the latter quality sufficient for close-to-shore work. The standard machinery installed comprised 2 x Boiler units feeding a single 4-cylinder triple-expansion steam engine driving a single shaft. The single shaft arrangement was of particular note and certainly limited maneuverability. Maximum speed could reach up to 16 knots and range was out to 3,500 nautical miles.

Aboard were 85 men and installed systems included an SW1C (2C series) radar fit along with Type 123A (or Type 127DV) sonar system. Armament centered on 1 x 4" BL Mk.IX turreted deck gun in the "A-Position" at the forecastle and, beyond this, 2 x Vickers 0.50 caliber heavy machine guns in twin-gunned mountings and 2 x .303 caliber Lewis Machine Guns in twin-gunned mountings were used for Anti-Aircraft (AA) defense. Submarine-hunting was accomplished by management of 2 x Mk.II depth charge launchers and 2 x Depth charge racks. The vessel could carry up to 40 depth charges into battle.

In time, the Anti-Aircraft (AA) fit was reworked for the better so gone were the machine guns and, in their place, arrived 2-pouner "Pom-Pom" cannons and 20mm Oerlikon automatic cannons. This vastly improved survivability against incoming enemy aircraft ready to strike at the vessel.

The silhouette involved the primary gun battery overlooking the bow and the bridge superstructure immediately aft of this. The sole mast work was positioned near midships ahead of the smoke funnel which had a distinct rearwards crank to it. The hull superstructure design tapered towards the stern and this clearance provided generally good all-around vision for the crew on watch. While the series was always intended for the minesweeping role, the applicable minesweeping equipment was eventually cut out to help improve the range of the vessel while also freeing up deck space.

The original ships were 225 built to the 1939-1940 standard while the follow-on batch, Modified Flower-class, were 69 ships built from 1940 onwards. The primary difference between the two batches was the latter's dimensions were slightly increased and armament improved to an extent.

During World War 2, use of the Flower-class fell to all of the major allies. The British and Canadian navies were prime operators of the series but the United States Navy (and Coast Guard service) also called these ships into service during the challenging period of 1942. Other Allied powers ultimately included Free French forces, Belgium, Greece, British India, the Netherlands, the Royal New Zealand Navy, the Royal Norwegian Navy, the South African Navy and the Royal Yugoslav Navy. The German Kriegsmarine managed capture of some of the stock from allies and put them to work under new ownership.

In the post-war world, the vessels continued in extended service, both in military and merchantman roles. Operators included Argentina, Bolivia, Chile, China, Denmark, Dominican Republic, Egypt, Greece, India, Israel, Ireland, South Africa, Thailand and Yugoslavia.

Out of the massive total of ships constructed, only HMCS Sackville (K181) of the Canadian Navy has been preserved as a museum ship (in Halifax, Nova Scotia).©MilitaryFactory.com
Note: The above text is EXCLUSIVE to the site www.MilitaryFactory.com. It is the product of many hours of research and work made possible with the help of contributors, veterans, insiders, and topic specialists. If you happen upon this text anywhere else on the internet or in print, please let us know at MilitaryFactory AT gmail DOT com so that we may take appropriate action against the offender / offending site and continue to protect this original work.


Service Year

United Kingdom national flag graphic
United Kingdom


Flower-class / Modified Flower-class

267 total vessels completed.

National flag of Argentina National flag of Belgium National flag of Bolivia National flag of Brazil National flag of Canada National flag of Chile National flag of China National flag of Denmark National flag of the Dominican Republic National flag of Egypt National flag of France National flag of modern Germany National flag of Nazi Germany National flag of Greece National flag of India National flag of Ireland National flag of Israel National flag of the Netherlands National flag of New Zealand National flag of Norway National flag of South Africa National flag of Thailand National flag of the United Kingdom National flag of the United States National flag of Yugoslavia Argentina; Belgium; Bolivia; Brazil; Canada; Chile; China; Denmark; Dominican Republic; Egypt; France; Greece; India; Israel; Ireland; Nazi Germany (captured); Netherlands; New Zealand; Norway; South Africa; Thailand; United Kingdom; United States; Yugoslavia
(OPERATORS list includes past, present, and future operators when applicable)
Offshore Operation
Activities conducted near shorelines in support of allied activities.

205.0 ft
62.48 m
33.0 ft
10.06 m
11.5 ft
3.51 m

Installed Power: 2 x Boiler units feeding 1 x 4-cylinder triple-expansion engine developing 2,750 horsepower to 1 x Shaft.
Surface Speed
16.0 kts
(18.4 mph)
3,498 nm
(4,025 mi | 6,478 km)

kts = knots | mph = miles-per-hour | nm = nautical miles | mi = miles | km = kilometers

1 kts = 1.15 mph | 1 nm = 1.15 mi | 1 nm = 1.85 km
1 x 4" BL Mk.IX turreted deck gun
2 x 0.50 caliber Vickers heavy machine guns in twin-gunned mountings.
2 x 0.303 caliber Lewis Machine Guns in twin-gunned mountings.
2 x Mk.II depth charge launchers
2 x Depth charge racks

Up to 40 depth charges carried.

Supported Types

Graphical image of a modern warship turreted deck gun armament
Graphical image of an aircraft medium machine gun
Graphical image of an aircraft heavy machine gun
Graphical image of a naval depth charge

(Not all weapon types may be represented in the showcase above)

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Images Gallery

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Image of the Flower (class)
Image from the Public Domain.

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