3-47
GB
EMU19160
Trim angle settings and boat handling
When the boat is on plane, a bow-up atti-
tude results in less drag, greater stability
and efficiency. This is generally when the
keel line of the boat is up about 3 to
5 degrees. With the bow up, the boat may
have a greater tendency to steer to one side
or the other. Compensate for this as you
steer. The trim tab can also be adjusted to
help offset this effect.
1
Optimum angle (level keel line)
2
Bow up
3
Bow down
Bow Up
Too much trim-out puts the bow of the boat
too high in the water. Performance and econ-
omy are decreased because the hull of the
boat is pushing the water and there is more
air drag. Excessive trim-out can also cause
the propeller to ventilate, which reduces per-
formance further, and the boat may “por-
poise” (hop in the water), which could throw
the operator and passengers overboard.
Bow Down
When the bow of the boat is down, it is eas-
ier to accelerate from a standing start onto
plane. Too much trim-in causes the boat to
“plow” through the water, decreasing fuel
economy and making it hard to increase
speed. Operating with excessive trim-in at
higher speeds also makes the boat unstable.
Resistance at the bow is greatly increased,
heightening the danger of “bow steering” and
making operation difficult and dangerous.
NOTE:
@
Depending on the type of boat, the outboard
motor trim angle may have little effect on the
trim of the boat when operating.
@
U68T73A0.book Page 47 Sunday, March 30, 2003 6:34 PM
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