CHAPTER 5
5-18
When the vessel begins to gather speed to stern, the water passing by
the lower gearcase housing will continue to increase steering torque.
If the helm wheel is turned to starboard, and will direct the propeller
thrust to port, tracking the stern to starboard.
Wind and current will affect how a vessel backs. Stern drive boats
tend to be light displacements and when backing down in a strong
crosswind, the bow will tend to fall toward the windward. This may
cause steering problems.
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
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