Let’s learn how to use Tidal Curves. Tide Tables will give you the Time and Height of High and Low Water but often we need to know Times and Heights for somewhere between the two. For example we may be entering a river with a bar or wanting to use a drying berth in a small harbour. The explanation below should make things clear.
At what Time will the Height of Tide be at a certain level, or what Height will the Tide be at a certain Time?
The use of the Tidal Curve is most easily explained with the help of the diagram below, this example answers the question ‘At what time will the Height of Tide reach 3.2 metres‘.
The example above shows us starting with a required height and we want to find a time, we can just as easily enter with a time to find a height.
The Red curve above is for Spring Tides, where it differs a dashed line for Neap Tides is also shown, interpolation by eye is used where required.
Tidal Curves for Standard Ports are found in Admiralty Tide Tables and Nautical Almanacs such as Reeds. For Secondary Ports use the Curve for the relevant Standard Port. The almanac will make it clear which Standard Port you need to refer to. For example, the Standard Port for Looe in Cornwall is Devonport (Plymouth).
For more information on Tide Tables Click Here.
For more information on Secondary Ports Click Here.
We do produce encapsulated Tidal Curves for Plymouth, Falmouth and Dartmouth which can be written on with a soft pencil and re-used. The reverse of the Plymouth Curve has a Secondary Port data from the Isle of Scilly to Exmouth.