Minesweepers are responsible for clearing naval mines.
Tips
memory
水 (water) + 雷 (thunder; later 'mine/explosive') = 'water-mine.' The same 雷 character builds 地雷 (land mine), 鱼雷 (torpedo, 'fish-mine'), and 雷管 (detonator).
usage
Naval mines come in two families in Chinese terminology: 触发水雷 (touch-triggered) and 非触发水雷 (non-contact, e.g. magnetic or acoustic) - terms you'll see in any military-history article.
