Reading & Interpreting a Tide Table:
Interpreting Tidal Diamonds on a nautical chart:
The Rule of 12ths is a rule that helps us estimate the height of tide at any given time with only the time and height of high water and low water as information.
The rule states that in the first hour after low tide, the water level will rise by 1/12th of the range, in the second hour 2/12th's and so on, as shown in the image.
Why are tides called Springs and Neaps?
The Shorter Oxford dictionary gives the derivation of 'neap' from the Old English (OE) word 'nep', to become lower. Thus the OE 'nepflod' tide gives as a rough translation 'low flood' tide