Raymarine i50 Depth Installation And Operation Instructions Manual page 48

Markers — side view
1. Front marker
2. Rear marker
When the 2 markers appear vertically aligned
the vessel is on the correct range line to begin a
measured mile run.
Marker alignment
1 2
1. Left of range line
2. On range line
3. Right of range line
The vessel should already be at top speed and as
the first pair of markers appear aligned a stopwatch
should be started, when the vessel passes the
second pair of aligned markers the stopwatch is
stopped.
Measuring a nautical mile
1
1. Starting point (start stopwatch)
2. Measured mile
3. End point (stop stopwatch)
4. First pair of markers
5. Second pair of markers
To provide a more accurate reading the vessel
should make between 4 to 6 runs in both directions
to allow for tide and wind conditions. The average
of the time taken over all runs should be used to
calculate Log Speed.
48
2
1
3
2
The vessel speed can then be worked out by taking
the distance travelled (1 nautical mile) and dividing it
by the average time taken to perform the run . The
resulting calculation is your average speed in knots.
Selecting unit of measure for water
temperature readings
From the User Calibration Menu:
1. Press the Speed button until the Water
Temperature Units page is displayed (5 presses
from the User Calibration entry page).
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2. Use the Timer or Reset buttons to select
the required unit of measurement for water
temperature readings.
The units of measure available for temperature
are:
• °C (default) — degrees Celsius
• °F — degrees Fahrenheit
Note: To exit the User Calibration pages at any
time, press and hold the Speed and Trip buttons
at the same time for approximately 2 seconds.
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Calibrating water temperature
You will need an suitable thermometer to measure
the water temperature.
From the User Calibration Menu:
1. Press the Speed button until the Water
Temperature Calibration page is displayed (6
presses form the User Calibration entry page).
2. Use a suitable thermometer to measure the water
temperature.
3. Use the Timer and Reset buttons to match
the displayed water temperature to the water
temperature measured by the thermometer.
Note: To exit the User Calibration pages at any
time, press and hold the Speed and Trip buttons
at the same time for approximately 2 seconds.
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Enabling and disabling timer buzzers
From the User Calibration Menu:
1. Press the Speed button until the Timer Buzzer
page is displayed (76 presses form the User
Calibration entry page).
2. Use the Timer or Reset buttons to switch the
timer buzzers On and Off (default).
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