a ship equipped like a lighthouse and anchored where a permanent lighthouse would be impracticable
lightship详细解释
light.ship n.Nautical （名词）【航海】 A ship with a powerful light or warning signals that is anchored in dangerous waters to alert other vessels.灯船：配有强光力的灯或警戒信号的船，停泊在危险的水域，使其它船只警觉
