Raymarine stand-alone master instrument - Manual (Page 36)

Chapter 6: Calibration 33
Log calibration
The ST30 Bidata should not be used for navigational purposes until the
transducer paddlewheel has been calibrated to suit the characteristics of
the vessel.
This is a simple operation and is carried out as follows:
1. Choose two charted points that are approximately 1nm apart.
Approximately 1Nm
Point 1 Point 2
D699
2. Choosing a time when the tidal flow is at a minimum, go from point 1
to point 2 and record the ST30 Bidata trip distance.
3. Go from point 2 to point 1 and record the trip distance.
4. Add the two distances together and divide by two to obtain an
average distance.
5. Measure the distance between the two points on a chart.
6. The correction factor (CF) can now be calculated.
CF = Charted Distance
Average Distance