《礼记·月令》
命令主管船只的官员将船翻转过来检查，这样翻来覆去地检查五遍，才向天子报告说舟船准备停当。天子这才开始乘舟，向宗庙进献时鲜的鲟鱼，以祈求麦子丰收。
命舟牧覆舟，五覆五反。乃告舟备具于天子焉，天子始乘舟。荐鲔于寝庙，乃为麦祈实。
Order the officials in charge of the ship to turn the ship upside down and inspect it, they check it five times this way, then report to the Son of Heaven that the ship is ready to set sail. Only then does the Son of Heaven board the ship and offer fresh sturgeon to the ancestral temple, praying for abundant wheat crops.