B&G H2000 Pilot *DISCONTINUED* - Manual (Page 93)

HB-0844-04
3-28
Using Scroll Up or Scroll Down until the one required value to be corrected
is found. In this example it would be "upwind, 10 knots". Having scrolled
through to this, press the Enter Key. This will allow entry of the required
number of degrees correction (i.e. +5). Use the Scroll Up and Scroll Down
Keys to increase or decrease the value accordingly.
Pressing the Enter Key sets this figure in the Hydra 2000 memory.
At initial calibration it is important to enter the same value of correction to the
wind speeds either side of the one you are using. This is to avoid the true
wind direction jumping in value when the wind speed drops or increases
outside the range you are correcting. When the table entries approach
completion it will be possible to enter individual changes as other corrections
will be accurate enough to avoid any strange "step" changes as the true wind
speed varies.
It is very important to enter all these corrections into a Calibration Chart. In
this way any large gaps in the correction table will be noticed where no
entries have been made.
3.6.2 True Wind Speed Calibration
True Wind Speed suffers from another, mainly aerodynamic problem, where
it tends to over-read downwind because of accelerated airflow over the top
of the mast. It is possible to correct for this by applying a downwind
correction to the True Wind Speed. This correction is applied at 180° true
wind angle and then linearly interpolated to zero at 90° true wind angle. Bear
away quickly from close-hauled to dead downwind and watch the increase in
true wind speed. Then the difference is entered as a negative correction.
The table will look similar to Table 3.2.
Wind Angle True Wind Speed
5 10 15 20 25 30
Downwind 180 0 -0.5 -1.0 -1.5 -2.0 -2.5
Table 3.2 - Example of True Wind Speed Correction Table
The corrections are found in the menu under:
WIND
→ → TRUE W/S, CALBRATE → → CORRECTION
They are entered in the same way as the true wind direction corrections.
Remember to enter the values on your correction chart in Appendix 1.
3.7
DEPTH CALIBRATION