Allowance for tidal streams 2

Let’s now consult the “Tidal Levels Table” which is located on the chart.
As we can see, the spring tidal range in Portsmouth is 4.4 meters high, MHWS (Mean High Water Springs), 4.4 meters minus MLWS (Mean Low Water Springs), 0.0 meters – equals 4.4 meters.
We now know that the rate of the stream is close to a spring rate, because the tidal range on September 2nd is 4.2 meters.
With this data we can enter the Tidal Stream Table, also located on the chart.
First we have to find out which tidal diamond is closest to our ground track.
The nearest tidal diamond is “A”.
Now, we select either the hours before High Water or after High Water.
Let’s assume that we want the set and the drift 2 hours before high water, i.e. for 08:39 hours.
Following the same line we read that the direction of the tide – the set, is 115 degrees, and the spring rate – the drift, is 2.3 knots.