Once increased headway is gathered in reverse gear, the force of the
lower hull moving through the water is enough to track straight. When
backing, the stern will lead as it heads to port or starboard, before the
vessel actually starts to turn.
When the control is put in forward gear position, the stern is pushed
to starboard; the amount of push depends on the hull design and the
amount of throttle advance. See illustration.
Stopping
Remember that your boat does not have
any brakes. It uses reverse thrust from the
propeller to stop. If the vessel has headway,
with the helm and propeller in reverse the
propeller thrust is directed backwards, past
the lower gearcase of the stern drive.
Depending on how far the throttle is advanced, the discharged thrust
may not be strong enough to reverse the water fl owing by the gearcase.
As the power is increased, the propeller thrust becomes strong enough
to stop the fl ow of water past the lower unit, and, as the throttle is
advanced it reverses its fl ow more completely.
When water is fl owing past the gearcase, steering torque is increased,
but when the thrust stops the water fl ow, the boat will not respond to
the helm. This is a short lived event and is overcome quickly when the
water again fl ows past the gearcase. Furthermore, added to the energy
of the water hitting the lower gear case, the propeller thrust is directed
by turning the stern drive, which can add to the steering torque.
The prop tends to throw the stern to port. This is why experienced
skippers undertake a port side landing when wind and current conditions
permit. They allow the prop to move the stern to port toward the dock.
With a forward motion when the helm wheel is turned hard to one
side, the vessel pivots around a point about 1/3 its length abaft to
stern. See illustration.
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