Operating manual ALPHASEAPILOT MFC Issue 1.1 Page 49 of 84
ALPHASEAPILOT MFC
2.20 Optimising the Rudder Control Setting
The RUDDER control provides the operator with the means to increase or decrease the angle of
rudder applied in relation to course error and should be adjusted to provide positive correction
of Yaw without oversteer (Section 2.19 refers).
NB. Certain types of vessel steering characteristics benefit greatly from the
anticipation afforded by a competent helmsman in applying short term exaggerated
angles of rudder in order to check or ‘counter’ yaw inertia as soon as ‘felt’. The
Autopilot Counter Rudder function produces a similar effect and it may prove
beneficial at a later stage to increase the COUNTER control setting by an amount,
which fully optimises the straight-line steering performance.
Under normal operating conditions (normal cruising speed and average sea state) the RUDDER
value will ideally be set at approximately mid range (No. 5 in the Controls Menu) to provide
operator scope for increase or decrease in significantly changed operating conditions.
In heavy following sea conditions or at very slow speeds, it is likely that the operator will need
to increase the RUDDER control setting whereas at full speed or when beating into sea the
RUDDER control setting will need to be decreased.
NB. Once the Adaptive calibration has been optimised versus Speed & Draft input data, the
RUDDER parameter adjustment will be automatic in the Adaptive operating mode. (Sections
2.29 & 2.30 refer).
If it is found that the maximum (No. 9) RUDDER value typically does not produce enough
rudder or, conversely, if the minimum (No. 1) RUDDER value typically provides too much
rudder, the entire band of control available to the operator can be increased or decreased by
corresponding Loop Gain adjustment via the Autopilot Set Up Menu as specified in section 2.21.
2.21 Optimising the Rudder Control Band
A RUDDER control value of No. 1 (Controls Menu) will produce 1/3
rd
(33%) of the angle of
rudder otherwise produced by a control setting of No. 9. The resultant 3:1 range available to
the operator can be calibrated via access to the Set Up Menu to produce actual degree of rudder
per degree of course error ranges (or bands) as follows:-
Loop Gain values:-
Minimum: 0.33°/° (N°1) to 1°/° (N°9) = rudder/degree of course error.
Maximum: 1°/° (N°1) to 3°/° (N°9) = rudder/degree of course error.
The factory default range setting for loop gain provides 0.5° to 1.5° of rudder
per degree of course error but as a general rule, the operating band via Loop
Gain calibration should initially be set as follows: -
Fast planing/semi planing vessels (HSC) - 0.33° to 1° per degree
Deep sea fishing vessels etc. - 0.5° to 1.5° per degree
Heavy displacement ocean going vessels - 1.0° to 3.0° per degree
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