Regal LS4C Owner's Manual page 100

Below is some basic information on how stern drive
boats handle in normal conditions.
Gathering Headway
When a stern drive is not moving forward or reverse
in the water and the propeller is not turning, (shift in
neutral) the boat will not react to the helm steering
wheel.
As soon as the vessel is shifted into forward gear
propeller action creates a discharge motion and
generates energy in the form of thrust. If the drive is
centered, the discharge motion is directed straight
back causing the vessel to advance forward.
You may notice that if you advance the throttle
quickly in initial take-off (make sure you have a firm
grip on the wheel), the boat has a tendency to pull
the stern of the vessel to starboard. There is a trim
tab (also serves as a sacrificial anode) located on
the drive housing. This trim tab helps compensate
for the low speed steering torque. Once the boat
increases headway and the propeller is operating
in a faster water flow this torque effect decreases.
Sometimes the trim tab may need adjustment.
Contact your Regal dealer for further information or
consult your engine manufacturer's manual.
Turning
Once the boat has gathered headway, with the boat
planing at the correct bow angle and the outboard
drive unit and helm straight the boat tends to stay
on a uniform course heading. To assure the boat
trim angle is correct use the chart plotter screen trim
gauge as a guide while activating the trim button on
the remote control panel.
When the helm wheel is turned to the right or
starboard, the drive unit is turned in the same
direction. The propeller's discharge force is directed
to starboard forcing the boats stern to port. Water
flowing past the hull strikes the stern drive gear
housing in its starboard side, creating additional
turning torque. The stern starts a move to port,
forcing the bow to starboard.
If the helm is turned to the left or port the drive turns
to port, the stern of the boat goes starboard as the
bow turns to port.
As the vessel operator gains experience, he will
better gauge each maneuver and speed situation.
In this way he will understand the handling
characteristics of his boat. He needs to keep the
safety of his passengers in the highest priority.
Backing Down
If your boat has the steering wheel and drive straight
with the control in reverse, the stern will be pushed
a bit to port by the reversing propeller thrust. This
tendency to back to port can be eliminated by
turning the drive to starboard.
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