Naval mine clearance was originally done by whatever type of vessel could easily be adapted to the task, paddle steamers proving particularly suited due to their shallow draught.
In both World Wars naval trawlers were used, as they were naturally suitable for wire sweeping.
In World War II this task was given to smaller trawlers of about 300 tons, larger ones being used for anti-submarine work.
There were also some conversions of ships originally built for other purposes for special minesweeping.
The ships selected were of varying origin and age and thus do not form a class as such.