中文翻译与英英解释

警戒艇；巡逻艇。

guard:    n. 1.警卫；警戒；看守。 2.防卫者；看守者；哨兵， ...

boat:    n. 1.小舟，小船，(小)艇，(大船所载)救生艇；帆船 ...

a boat that is on guard duty (as in a harbor) around a fleet of warships