What is the relationship between “Tides” and “Tidal Currents”?
The vertical rise and fall of the tides, created by the gravitational force of the Moon and Sun acting on the oceans water, also creates a horizontal motion of the water in the bays, harbors and estuaries. These are tidal currents. In general, as the tides rise there will be a current flowing from the oceans into the bays, harbors and estuaries; this is termed a “flood current”. As the tides fall there will be a current flowing towards the oceans; this is termed an “ebb current”. There are also periods when there is little or no horizontal motion of the water; this is called “slack water”. Many professional and recreational users of tide and tidal current information have a “rule of thumb” to assume a relationship between the times of high/low tides and the times of the currents. That the times of slack water will be at the same time as the high and low tides, and that the flood and ebb current will occur between the high and low tides. Unfortunately, this assumed “rule of thumb” does
