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See "Sailing
parameters" on page 45 for
further information.
42 |
The set course to steer (CTS) and set wind angle are entered from the compass heading
and the wind transducer at the moment the WIND mode is selected. From that point the
autopilot will change the course to maintain the wind angle as the wind direction may
change.
Tacking
¼ Note:
The tack function is only available when the system is set up for SAIL boat type.
Tacking should only be performed into the wind and must be tried out in calm sea
conditions with light wind to find out how it works on your boat. Due to a wide range of
boat characteristics (from cruising to racing boats) the performance of the tack function
may vary from boat to boat.
You can initiate the tack function both from AUTO and from WIND mode.
In both modes you can interrupt the tack operation, as long as the tack dialog is open,
by selecting the opposite tacking direction. When interrupted the boat will return to the
previous set heading.
Tacking in Auto mode
Tacking in AUTO mode is different from
tacking in WIND mode. In AUTO mode
the tack angle is fixed and as defined by
the user.
When tacking direction is selected the
autopilot changes the current set course
according to the set fixed tacking angle.
Tacking in Wind mode
Tacking in WIND mode as compared to
AUTO mode can be performed when sailing with apparent or true wind as the reference.
The true wind angle should be less than 90 degrees.
The rate of turn during the tack will be given by the Tack time defined in the sailing
parameter setup (refer illustration above). The tack time is also controlled by the speed of
the boat to prevent loss of speed during a tack.
When you initiate the tacking, the autopilot will immediately mirror the set wind angle to
the opposite side of the bow.
Gybing
Gybing is possible when the true wind angle is larger than 120°.
The time to make a gybe is determined by the speed of the boat to make it as quick as
possible within control.
Tack and gybe prevent
You should use the autopilot with care when beating and running.
If the sails are unbalanced when beating, yaw forces from the sails can drive the boat
into the wind. If the boat is driven beyond the set minimum wind angle, the thrust from
the sails will suddenly disappear and reduces the boat speed. The boat will then be more
difficult to steer as the rudder will become less effective.
The tack prevent function in WIND mode has been implemented to avoid such situations.
It will react immediately when the apparent wind angle becomes 5° less than the set
minimum wind angle, and more rudder will be commanded.
When running, it is difficult to steer the boat with waves coming sideways or from behind.
Autopilot |
NSO-II Operator Manual
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