An example of how this worked in practice is provided by VIncent P. O'Hara, The German Fleet At War 1939-1945, p. 44, about the second battle of Narvik on 13 April 1940 where Warspite escorted by nine destroyers sank eight German destroyers trapped in the harbour:Knouterer wrote:Geoff Hewitt, in Hitler's Armada - the Royal Navy & the Defence of Great Britain April - October 1940, lists a number of destroyers as fitted with minesweeping gear, including (mid-Sept.) Icarus, Impulse and Vimiera at Sheerness/Chatham, Isis at Plymouth, Javelin, Jupiter, Jaguar and Kelvin at the Humber, Jackal, Kashmir, Kipling, Electra, Vega and Verdun at Rosyth, and a few more here and there.
Norman Friedman, in his second volume on British Destroyers & Frigates, provides some more info on this (page 10):
"As for mines, British practice was to equip many destroyers with the Two-Speed Destroyer Sweep (TSDS). That in turn required winches and fittings on the quarterdeck. TSDS was conceived as a search rather than a clearance sweep, ie a means of protecting the fleet (or at least detecting minefields) while on passage; hence its presence on board destroyers. It was expected to cut all unprotected moored mines, as well as a proportion of moored mines with anti-sweep devices; the percentage would increase with sweep speed and depth. Unlike all other sweeps, TSDS could be used at up to 25 kts. However, at speeds above 12 kts the swept swath was narrow. Doctrine called for four destroyers steaming and sweeping abreast of a column of battleships."
However, the TSDS did not provide any means of sweeping non-contact mines, such as magnetic mines.
"The British continued up the fjord with Icarus in the lead sweeping with bow paravanes and Foxhound and Hero with stern sweeps (TSDS) to either side, clearing the way. Starboard of Warspite sailed Bedouin, Punjabi and Eskimo; to port proceeded Cossack, Kimberley and Forester."
As discussed before, according to international agreements moored contact mines should have been fitted with some device to render them harmless when the chain/cable was cut, but as also discussed such devices, if fitted, seemed to malfunction very often, making "floaters" a serious hazard.