试析中国古代的航海计程单位“潮”

An Interpretation of “Chao”——The unit for Calculating Distance Traveled in Pre-modern Chinese Maritime Navigation

"潮"是中国古代一个重要的航海计程单位,潮汐"自涨而落或自落而涨"称为"一潮",古人以两地航道沿途潮汐相继发生的次数(或需要候潮的次数)表示航程的远近。宋代至清代,以"潮"计程之法经常被运用到东南沿海的短距离近岸航海活动中。以"潮"计程是古人对于潮汐充分认知和熟练运用的一个重要例证。

The term chao designated an important unit for calculating distance traveled in pre-modern Chinese maritime navigation. One chao was one fluctuation of tide. It used the tide times in sea navigation to show the distance between the two places. From the Song to Qing dynasties, the chao was often used in short distance navigation activities in the coastal area of southeastern China. The tide as a unit for calculating distance traveled was a manifestation of full understanding and mastery of the tide by our forebears.