The difference between high and low water is approximately six hours. The rate of flow between high and low water can be generalised by the ‘Rule of Twelfths’. The diagram below illustrates how much water flows during a given hour.


最近的⾼潮到低潮之间，时间相差⼤约为六⼩时。在⾼潮与低潮之间，海⽔升降的速度可以 通过“⼗⼆分之⼀法则”来进⾏概括。下图说明了在每个⼩时内⽔流变化情况。


The greatest movement of water is during the middle two hours and the least either side of low and high water.


在这六个⼩时中，中间的两个⼩时（第三⼩时和第四⼩时）⽔流最强，⽽在⾼潮和低潮前 后，⽔流最弱。


If we take the two middle hours – the third and fourth hours – we can see that 6/12ths or half of the water will flow during this time. This shows that during this time frame we experience the fastest tidal flow.


如果你观察第三和第四个⼩时，会发现在这段时间内将会有6/12（即⼀半）的⽔量流动，这 说明这⼀时段潮流速度最快。


You will notice that, during hours one and six, only 1/12th of the water will flow during each of these times. Therefore, this is the slowest tidal movement during the six-hour period.


⽽在第⼀个⼩时和第六个⼩时内，每⼩时仅有1/12的⽔量流动，因此，这两个时段是六⼩时 周期中潮流最缓慢的时候。


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