Alphatron ALPHASEAPILOT MFC - V) Autothrust; VI) Turn Type (ROT or RAD)

Operating manual ALPHASEAPILOT MFC Issue 1.1 Page 30 of 84
ALPHASEAPILOT MFC
2.4 (v) Autothrust
The Autothrust Mode refers to Autopilot control of the Thruster(s) which may be confined to
Thruster ONLY or combined with Rudder to provide Rudder AND Thruster response to
Autopilot steering demands.
The amount of Thruster power required – whether alone or combined with Rudder – will
vary over a very wide range dependent upon vessel speed, laden condition and external
forces (towing/windage/Set etc.).
From the viewpoint of Adaptive Autopilot control and performance, automatic adjustment of
the Thrust value (amount) is time consuming and inefficient compared with the
straightforward and immediate result gained by manual adjustment.
For this reason, the Autothrust parameter may often be changed manually via access to the
CONTROLS Menu.
(Related operational conditions would involve vessels underway at low speeds due to
towing, winching or navigational considerations, where all conditions combined to degrade
Autopilot course keeping when using Rudder(s) only. In this case, the Rudder Mode of
control would be retained but would be assisted by the introduction of Bowthruster action
via selection of the Autopilot RUDDER + THRUSTER Mode. Manual value adjustment of the
Thruster contribution would then be made to rapidly optimise steering performance).
To adjust AUTOTHRUST gain:-
a) Use the “CONTROLS” key to enter the Controls Menu.
b) Use the “CONTROLS” key again to select “AUTOTHRUST” box followed by
flashing value “1-9” (where 9 = max. thrust).
c) Use the rotary (+/-) illum. control to set value “1-9” as required.
2.4 (vi) Turn Type (ROT or RAD)
Rate of Turn (ROT) and Radius of Turn (RAD) control is provided by the Autopilot system
and can be active - if selected via the CONTROLS Menu - in both the Adaptive and Non
Adaptive Autopilot operating modes.
If no ROT or RAD control is required, the facility can be set to “OFF”.
Radius of Turn Operating Note:-
It should be noted that Speed input data is essential to Radius of Turn control in the form of
Speed over the Ground (SOG). If SOG data is absent, or, if vessel SOG is too low to
maintain the constant radius turn demanded versus prevailing conditions, Autopilot alarms
will result.
NO SOG DATA = NO RADIUS OF TURN CONTROL FACILITY.
Rate of Turn Operating Note:-
Rate of Turn (ROT) is reliant upon Autopilot system internal calculation based on change of
heading and does not require Speed input although it must be noted that Speed through the
water (STW) is essential for Speed Adaptive Autopilot operation.
NO STW DATA = NO SPEED ADAPTIVE AUTOPILOT OPERATION.