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, 16knot whale catcher Southern Pride.[1] [2] 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 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.[3]
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.
Gardenia was laid down by William Simons and Company at their shipyard at Renfrew, on 20 September 1939 and launched on 10 April 1940. She was commissioned on 24 May 1940.
Gardenia collided with and sank off Oran, Algeria on 9 November 1942.[4]