Not necessarily an answer to your question, while we are on the subject of tides...
This is a good
rule of thumb when gauging the strength of a tide at a given time. I used it when commercial fishing in an area that had up to 25ft tides.
Example
If a flood or ebb tide is ~6 hours
The tide is rising 18ft ( I know the rest of you are metric, but it will have to do
)
1st hour = 1/12th of the total movement of the tide which = 1.5 feet
2nd hour = 2/12ths of the total movement of the tide which = 3 feet
3rd hour = 3/12ths of the total movement of the tide which = 4.5 feet
4th hour = 3/12ths of the total movement of the tide which = 4.5 feet
5th hour = 2/12ths of the total movement of the tide which = 3 feet
6th hour = 1/12th of the total movement of the tide which = 1.5 feet
Not all tides are 6 hours so you just take the know tide time length divided by 6 even periods of time. if you have a 7.5 hour tide you would have 6 time periods of 1 hour and 15 minutes each. The water movement would happen in the first 1 hour and 15 minutes and the last 1 hour and 15 minutes would be 1/12th each (of the total flood or ebb tide)
Note that 1/2 of the tide moves in the middle 2 periods of a tide.