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Lunitidal Interval
Theoretically, it is said that high tide (peak
tide) occurs when the moon reaches the
meridian (Figure 1), and low tide (ebb tide)
occurs about six hours later. However, in the
real world, the effects of seawater viscosity,
friction, and sea floor topography delay the
high tide to some point after the meridian
(Figure 2). This time differential is the “lunitidal
tide interval”.
The lunitidal interval differs from one region
(port) to another, even within the same country
or geographic area.
Figure 1
Tidal force is at its peak when the Moon is at
the meridian.
Earth
Moon
Tidal force
Figure 2
The actual high tide occurs a number of hours
after the Moon meridian.
Moon
Earth
High tide
Stopwatch
The stopwatch measures elapsed time in units
of 1/100 second up to 23 hours, 59 minutes,
59.99 seconds (24 hours).
When this maximum limit is exceeded,
elapsed time measurement returns to 0 and
timing continues from there.
Measuring Elapsed Time
1.
Enter the Stopwatch Mode.
l
Hour, minute, second
1/100 seconds
2.
Use the operations below to measure
elapsed time.
D
D
D
D
Stop
Resume
Stop
Start
3.
Press (A) to reset the stopwatch to all
zeros.
Measuring a Split Time
1.
Enter the Stopwatch Mode.
l
Hour, minute, second
1/100 seconds
2.
Use the operations below to measure
elapsed time.
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Pressing (A) displays the elapsed time
from the start of a race up to the point
when you pressed the button (split
time).
D
A
A
D
Stop
Split release
Split
Start
3.
Press (A) to reset the stopwatch to all
zeros.
Watch Operation Guide 3522
13