520 Express Series
7-7
CSR-159-18
PROPELLER “BURSTS” AND
STOPPING
Propeller burst is a maneuvering technique
requiring fairly moderate speed (800-1000
RPM) and using shift controls only. Move
shift lever of port or starboard engine to
FORWARD or REVERSE for short intervals
to maneuver the boat into the desired
position.
Stopping the boat’s forward movement
(checking headway) using propeller bursts
will reduce the distance required to stop.
With engine speeds equal, move both shift
levers to REVERSE to slow or stop forward
movement.
TRIMMING THE YACHT
When the yacht is accelerated forward, its
trim angle increases causing the bow to ride
high and the stern low. Continued
acceleration will bring the trim angle to a
maximum angle (“hump”); then the yacht will
level out to its planing attitude.
It is important to get “over the hump” as soon
as possible due to the reduced visibility,
handling and performance. A few seconds at
full throttle should get the yacht over the
hump and into a planing attitude. Once you
are “over the hump” and at a comfortable
plane, move the throttle control back to 2/3
to 3/4 throttle, a more fuel efficient cruising
speed.
WARNING
DO NOT overtrim. The yacht may
veer or the bow may dig in causing
you to lose control.
When accelerating to cruising speed, lower
trim tabs to assist the yacht up at the stern
and into a planing attitude quickly. As water
passes under the hull, it contacts the trim
tabs forcing the stern up. Change the angle
of the trim tabs to change the rate of lift;
lower tabs result in faster lift.
Until you become familiar with trimming your
yacht, move the rocker switches in half-
second intervals. The yacht will not react
immediately; it will take a few seconds.
Trim tabs can also be used to control uneven
weight situations while underway. For a
heavy stern, lower trim tabs equally until a
comfortable plane is achieved. If the port or
starboard is heavy, lower the trim tab on the
heavy side to a point where the yacht levels
out.
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