The turbine ships used the same shorter hulls as Niger and Salamander, but with lower power, speed dropped back to 16.5 kn (31 km/h; 19 mph).

Gleaner, Franklin, Jason and Scott were completed as unarmed survey vessels, Sharpshooter and Seagull being converted to follow suit.

J. R. N. Taylor, RN) was sweeping an area 15 nmi (28 km; 17 mi) north of Kinnaird Head when it was attacked by German aircraft.

A bomb pierced the forecastle deck and exploded, destroying the fore part of the ship and killing the commanding officer and forty of his men.

F. B. Proudfoot, RN) was attacked and sunk by a force of German dive bombers off De Panne, Belgium on 1 June 1940.

Four Halcyons were lost during this period, Hebe and Speedy served in the Mediterranean as part of the 14th/17th Minesweeper Flotilla based in Malta.

On the afternoon of 27 August 1944, they were sweeping off Cap d'Antifer in preparation for the battleship Warspite and the monitors Erebus and Roberts to engage Le Havre coastal artillery delaying the advance of Canadian troops.

The squadrons attacked with 16 Typhoons armed with 20 mm cannon and High Explosive "60 lb" RP-3 unguided rockets.