In March 1941, Orchis was the first ship fitted with the very successful 10-cm wavelength Type 271 radar enabling detection of a surfaced submarine at or a submarine periscope at . Orchis was assigned first to the 4th Escort Group based at Greenock[1] and then to Escort Group B3 of the Mid-Ocean Escort Force through early 1944.[2] Orchis escorted convoy ONS 18 during the battle around this and ON 202.[3]
Orchis was then assigned to patrol the English Channel, and sank the on 15 August 1944.[4] U-741 torpedoed LST-404 of convoy FTM-69 while Orchis was escorting nearby convoy FTC-68. Orchis gained and held sonar contact on U-741 and flooded the forward part of the U-boat with two Hedgehog attacks and two depth charge attacks. One person escaped from the aft torpedo-room hatch of the sunken U-boat, and was rescued by Orchis.[5]
On 21 August 1944, Orchis struck a mine that destroyed the bow back to the 4-inch gun. The damaged ship was beached on Juno Beach and declared a total loss.[6] [7]