Section 11: Tides
Tides divides conveniently into three more digestible chunks: i) theory of tides, how they work and why they work in way they do, ii) tidal height, how we find how high the level of water is above chart datum at a particular time and place, and iii) tidal streams, how we find the direction and rate of flow of the tide at a particular time and place.
We deal with them in this section in that order.
The section comprises the following:
Theory of tides, spring and neap tides, chart datum and highest astronomical tide
Relationship between height of tide, depth of water, and clearance under overhead obstructions
Height of high and low water at standard and secondary ports
The rule of twelfths
Use of the tidal rise curve
Tidal streams, tidal diamonds and tidal stream charts.
Weather effects on tides