Regal LS4C Owner's Manual page 149

Trim Tabs
If installed, trim tabs are located on the lower hull
of the transom. Water is deflected and redirected
as the trim tabs are raised and lowered from the
starboard helm located trim tab switch. This change
in water flow creates upper pressure under the
tabs, and raises the stern. When the stern rises the
bow is lowered. Lowering the port tab will cause
the port stern to rise, making the starboard bow
lower. Lowering the starboard tab will cause the
starboard stern to rise, making the port bow lower.
The pressure originates from a pump and valve
system located in the aft bilge.
TYPICAL TRIM TAB PANEL
distribution, listing, water conditions, and other
factors that cause inefficient operation. Remember,
that trim tabs are trimming the hull while power trim
is trimming the stern drive.
W h e n u s e d
with the engine
power trim a fine
tuned ride can
b e a c h i e v e d .
The trim tabs will
compensate for
uneven weight
Obtaining A Trimmed Position
Your vessel will reach a planing position at a specific
speed. This speed is determined by bottom design,
weight distribution, water conditions, and on board
equipment. As the throttle is advanced the stern
squats and the bow rises initially. The trim tabs allow
your boat to plane at a slower speed than natural
conditions allow. Note a stern drive example above.
In short bursts both trim tab rocker switches are
pushed simultaneously in the "bow down" position
which causes the trim tabs to move down. As the
boat breaks over the bow high attitude the boat
speed accelerates and visibility increases.
If the boat is over-trimmed, it will plow the bow and
the boat will lose maneuverability. If this occurs,
simply short burst the "bow up" trim tab rocker
switches simultaneously.
In the "learning curve" process, press the tab
switches in half second bursts. You will notice a
slight delay from the time the switches are pushed
until the boat reacts depending on vessel speed.
You will know after awhile the optimum planing angle
and speed/rpm for your vessel.
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