Understanding Tides
©
By Rich Johnson
Two of the questions I’m asked most often are "what and
how do tides work" and "what is the difference between flood and ebb, incoming
or outgoing" etc. Both very good questions which could take me a while to answer, but
I will try to simplify the basic explanations in this week’s column. The first thing
I should give readers is terminology to phrases and what they mean. Also understand tides
change twice a day, everyday.
We’re all familiar with the terms High or Low tides. They are just what they say
they are, 
high tide is the height in feet of the highest
point of the tide and low tide is the lowest height of the tide and these can vary from
place to place. Tides come in through the inlets and go out the same way, thus terms like
incoming and outgoing are self-explanatory. Since tides have to come in to rise to a high
tide or go out to create low tides you have terms like flood or ebb tides. Flood or
"flooding" water is the incoming of seawater to create a high tide and
Ebb or ebbing tide is the outgoing of seawater to create a low tide.
We must also remember there is a window of time between high and low tides where the
tide as we call it "rests." The flow of water comes to a halt for a period of
time before it moves in the opposite direction again, if it didn’t we would have high
and low tides at the same time every day which of course isn’t the case. Just as in
natural science class, we learn when you throw a ball into the air, it must come to a
finite point where it completely stops its upward movement before gravity takes over and
the ball falls to earth again. In the movement of water and tides the same thing is true.
The flooding or ebbing of a tide must stop before it can go in the opposite direction, we
call this "slack" water. In other words the tide has stopped moving and is slack
with no movement up or down. However this period or window of time can vary from day to
day and particularly on full or new moons. While the slack period of a tide may be
35 minutes off the moon, the window of slack tide on a moon may only be a few minutes
before the turnaround of the tide. This is why high and low tides are different every day.
You have two high tides and two low tides within every 24-hour day and the time of
slack water may be different between each. One other thing to remember is just because a
tide is high at a certain inlet does not mean it’s high tide in the back bay
estuaries. For example, I fish out of Jones Inlet and when it’s high tide at 12 noon,
high tide in the back bay around let’s say the Wantagh Bridge, could be as much as
1-1/2 hours later. If you can learn this about tides and fish the right tides, you should
greatly increase your catch production. One other thing, there’s an old adage that
says, "when the tide rests (slacks), so should the fishermen. More times than not,
this is true on game fish.
