Volvo Penta D4 Operator's Manual page 57

Operating with the drive in the Trim range
The Trim range is used to achieve maximum comfort un-
der normal operation at all speeds from start to maximum
speed.
Since every boat has its own unique characteristics and
will be effected in different ways by the factors involved,
only general advice is given here on how to get the best
trimming angle for your boat. It can generally be said that
when the boat feels well-balanced, easy to steer and
pleasant to operate, then that is the optimal trim angle for
the boat.
To familiarize yourself with the Power trim, make test runs
at slower speeds and at various trim positions to see
the effect ot trimming. Note the time it takes for the boat
plane. Watch the tachometer and speedometer readings
and the ride action of the boat.
When starting
Trim the drive in. The bow will be pressed down and the
boat accelerates faster. This gives improved running
and steering characteristics at speeds below the planing
threshold.
Operating in "Bow-down" Position
The "bow-down" position is normally used for acceleration
onto plane, operating at slow planing speeds, and run-
ning against a choppy wave condition. In the fully "bow-
down" position the boat may tend to selfsteer. You may
have to compensate with the steering wheel to keep the
boat in a straight-ahead path. In this position the boat's
bow will tend to go deeper into the water. If the boat is
operated at high speed and/or against high waves, the
bow of the boat will plow into the water. The boat may
tend to bow steer or spin about rapidly and possibly eject
occupants.
IMPORTANT! The boat trim should be adjusted
to provide balanced steering as soon as possible
each time you get underway. Some boat, engine,
and propeller combinations may encounter boat in-
stability and/or high steering torque when operated
at or near the limits of the "bow-up" or "bowdown"
positions. Boat stability and steering torque can also
vary due to changing water conditions. If you expe-
rience boat instability and/or high steering torque,
see your Volvo Penta dealer to correct these condi-
tions.
At planing speed
Trim the drive out to the operating position which provides
the most stable and comfortable running.
If the boat has twin motors the drives can be trimmed
with different angles to compensate for side winds and to
a certain extent compensate for uneven loading on one
side of the boat or the other.
Operation
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