Page 28 of 38
2021-06-24
CU-M001 User manual
B
A
Figure shows plotting a
calibration path on the chart.
The leg should take at least 3
minutes to sail (distance can
be shorter when sailing slowly).
Depth should be < 120 m to ensure
that bottom track also calibrates
correctly.
Sea test (Speed Calibration):
The Sea test method of calibration takes account of water current, and drag of the water by the vessel
(that may cause lower measurements for STW) This should be performed when the vessel is new,
the sensor is changed, or if the calibration data is questioned or deemed low quality by the systems
internal control systems. (See status page)
The vessel is made to sail a known distance and course in both directions. This to remove any water
current factors from the speeds. If a current is present, the 1st leg may show a different speed to the
2nd leg, however by sailing in opposite directions, the average will be correct.
Sea test method
:
Find a time and area with low sea state and low wind. In an area where the depth is <120m and
where there is little or no current .
Plot a line on the chart, that will take minimum 3 minutes to sail. (For a calibration at 15 knot you will
need a distance of at least 0.75 nm
