HMS Coreopsis took 333 days from laying down to commissioning. Even a simple escort design needed most of a year to enter service, so during roughly the first year of war the Royal Navy fought with escorts already available. Frigates and Castle-class corvettes could change convoy organization and the balance between shipping losses and U-boat kills only after enough ships entered service, with new hulls still arriving through 1941 and 1942. One of the last Flowers took 330 days, only three days less than Coreopsis, despite the scale of the building programme. The class was eventually credited with involvement in as many as 52 Axis submarine sinkings, but that contribution depended on completed ships arriving steadily.
Notable Point · 15:05-18:10
Why a simple escort still took almost a year
Flower corvettes were deliberately simple, yet construction still took roughly eleven months, so escort shortages shaped convoy organization and shipping losses for years.