Maneuver With Cruising Ship - Aventics Marex OS II Bedienungsanleitung

Movement of the lever from neutral to ahead or astern
If the lever of the active control head is
moved beyond the detent ahead or the
detent astern, the clutch engagement
procedure of the control passes as
follows:
1. Engine speed increase from idle
speed to a clutch engagement
speed in order not to stall the
engine during clutch engagement.
2. After the rpm increase the control
waits for a short time before the
gear is engaged.
3. Gear shifting to ahead or astern.
4. Maintaining of the increased clutch
engagement speed for a short time
to make sure that the engine is not
stalled due to the sudden load.
5. Further increase of the engine
speed up to the current set value by
the control head lever.
The modification of the engine speed from idle to clutch engagement speed or from clutch engagement speed to idle
speed is not carried out abruptly. In the control maximally possible velocities of the rpm modification are stored in a so-
called acceleration curve making sure that the engine is not loaded unnecessarily heavily during rpm modifications.
If the engine speed is further increased after the clutch engagement procedure according to the value set by the lever,
the rpm modification is also effected with a maximally possible velocity according to a second acceleration curve. This
acceleration curve is usually more slowly than the acceleration curve for the clutch engagement procedure, as now the
engine is loaded by the vessel to be driven. In addition, the velocity of the rpm modification can be decelerated again in
case of a higher engine speed.
Even if the steersman moves the lever of the control head from neutral jerkily to full ahead or full astern, the control will
use the acceleration curve for an optimized acceleration of the engine speed. In this way, an overload of the engine and
therefore also vibrations and too high exhaust gas emissions are securely avoided.
5.4

Maneuver with cruising ship

In case of a maneuver with cruising vessel the speed of
the vessel must be considered in relation to the water
(speed through the water).
If the gear is engaged, the propeller will be driven by the
engine.
If the gear is shifted to neutral, the so-called windmill
effect occurs. The propeller is no longer driven by the
engine, but by the water streaming along.
If the gear is shifted in contrary direction in a reversing
maneuver, the engine must work against the windmill
effect. In case of an unaligned reversing maneuver this
effect usually leads to stalling of the engine.
The Marex OS II remote control can securely avoid
stalling of the engine by maintaining a waiting time during
the reversing maneuver. The duration of the waiting time
adapts to the extent of the windmill effect and the current
ship velocity and the cruising direction. This waiting time
can be newly calculated and optimally adjusted by the
Marex OS II control for each reversing maneuver. In this
way the distance for stopping the vessel can be
minimized.
set speed set speed
clutch engagement speed clutch engagement speed
idle idle
waiting time before waiting time before
clutch engagement clutch engagement
output: set gear position output: set gear position
ahead ahead
astern astern
The clutch engagement speed is calculated by the control automatically. It
can lie between idle speed and the maximally admissible engine speed for
clutch engagement indicated by the gear manufacturer.
The delay times can be so short that they are not recognized by the
steersman. They are optimized during the commissioning of the remote
control.
detent neutral detent neutral
ahead ahead
waiting time waiting time
after clutch after clutch
engagement engagement
acceleration curve acceleration curve
engine engine
engine engine
time time
time time
ahead ahead
gear gear
neutral neutral
gear gear
wind mill effect wind mill effect