P
E R F O R M A N C E
4–1
C h a p t e r 4 : P e r f o r m a n c e
P
ERFORMANCE
F
ACTORS
Maximum performance is dependent on many factors and cannot be guaranteed. These factors
will vary with changing conditions. Some of these factors are listed below. Reference the trouble-
shooting guide on page 65 in
Sportfish, Cruisers, Yachts Owner’s Manual
.
E
NGINE
E
FFICIENCY
Assuming your boat is equipped with the correct engine, the engine is properly tuned and the
drive system is in good condition, operation will be most efficient at the RPM stated in the engine
manual. Efficiency, power, and speed will decrease if normal care and maintenance are not
performed. In addition, expensive repairs may become necessary. Be sure to follow all
instructions in the engines’ Operation Manuals.
W
EATHER
C
ONDITIONS
Weather conditions sway engine performance. Barometric pressure and humidity affect
horsepower. A change of weather could amount to a 10% loss in horsepower on some hot days.
L
OAD
D
ISTRIBUTION
A decrease in performance will be noted when gear, equipment, passengers, and fuel are
added. This extra load will affect the performance of your boat according to the distribution of the
weight. Another type of extra load that could affect performance is the accumulation of water in
the bilge. Keep the bilge dry to eliminate this type problem.
M
ARINE
G
ROWTH
Maximum performance is only obtained when your hull bottom is clean. Growth on the
bottom of the boat will increase resistance and decrease speed. These conditions will also increase
fuel consumption. See
“Cleaning” on page 6–1
for more information.
T
RIM
Most outboard models are equipped with power tilt and trim mechanisms. The purpose of
power tilt is to raise the engine for launching, loading or trailering. Power trim may be used to
adjust the boat’s planing performance and running attitude. See power trim, page 52 and 72, in
Sportfish, Cruisers, Yachts Owner’s Manual
.
N O T I C E
Most drive units are equipped with an adjustable rudder trim tab. This trim tab should be
adjusted to balance the steering at the speed which you travel most frequently. Variations in
speed, boat load, or changes in the drive unit trim will cause the steering to pull
in one direction. If the boat pulls to the left, adjust the trim tab to the left and vice-versa.