In the Spring and Autumn period (春秋 chūn qiū,770 -- 221BC), the Wu State (wú guó 吴国 ) and the Yue State (yuè guó 越国) often dig up the hatchet with each other,which sew the seeds of hatred in the heart of both people of the two countries. During one year,both states were seriously strikened by the flood. They had to row the same boat since the severe boat shortage at that time. When the boat went to the middle of the river, there blew a strong wind. The boat rocked in the water. The people of the two countries worked in full cooperation and with unity of purpose. In the end, they all went shore safely .

Nowadays,"Crossing a River in the Same Boat "means pulling together to overcome difficulties.

春秋时期，吴国和越国经常互相打仗。两国的人民也都将对方视为仇人。有一次，两国的人恰巧共同坐一艘船渡河。船刚开的时候，他们在船上互相瞪着对方，一副要打架的样子。但是船开到河中央的时候，突然遇到了大风雨，眼见船就要翻了，为了保住性命，他们顾不得彼此的仇恨，纷纷互相救助，并且合力稳定船身，才逃过这场天灾，而安全到达河的对岸。

现在，这个成语就用来行用人们齐心协力，共同度过难关。

同舟共济 (tóng zhōu gòng jì)
【翻译】Crossing a River in the Same Boat.
【释义】舟：船；济：渡，过河。坐一条船，共同渡河。比喻团结互助，同心协力，战胜困难。也
            比喻利害相同。
【例句】面对全球经济的不景气，公司的总经理们都号召公司的员工同舟共济，共同度过难关。
【近义词】患难与共、风雨同舟
【反义词】反目成仇、各行其是