"Duchess of Fife"

Hi Tycho -
Here's some information about it (and another mine sweeping paddle steamer) from a Flickr friend.
Duches of Buccleuch -
Ordered by the North British Railway Co and intended for use on the Forth by the Galloway Steam Packet Company of Leith (a company which North British controlled). In the event she was requisitioned by the Admiralty and completed as a minesweeper.
Note ; Duckworth & Langmuir in "Railway & Other Steamers" have the launch and completion dates in 1915. 1923 Broken up at Llanelly.
The Duchess of Fife had a much longer life:
www.clydesite.co.uk/clydebuilt/viewship.asp?id=790
I do not think there was any special reason to employ these paddlers for minesweeping other than they were available for such use. No doubt considered 'expendable' too!
On view in this shot (I think) is a marker buoy. Once a mine was located the marker would be dropped to locate the offending article. Then a follow-up vessel would arrive and destroy the mine (a sharp-shooter with a rifle).
I am also guessing the gear on show here handled the sweeping line, streamed out behind the mine sweeper. At the end was a 'paravane' - a torpedo-shaped buoy attached to the cutting wire, which by virtue of its shape tended to keep the cutting wire at close to right-angles to the passage of the ship. Any moored mines would have their under-water wires cut and the mine would then pop up to the surface and be visible for destruction.
All in all a dangerous task.....