90-826148R2 MARCH 19971C-2 - IMPORTANT INFORMATION
Boat
WEIGHT DISTRIBUTION
1. Proper positioning of the weight inside the boat
(personsandgear) hasa significant effect onthe
boat’s performance, for example:
a. Shifting weight to the rear (stern)
(1.)Generally increases top speed.
(2.) If in excess, can cause the boat to por-
poise.
(3.) Canmakethebowbounceexcessivelyin
choppy water.
(4.) Will increase the danger of the following
-wavesplashing into theboatwhencom-
ing off plane.
b. Shifting weight to the front (bow)
(1.) Improves ease of planing off.
(2.) Generally improves rough water ride.
(3.) If excessive, can make the boat veer left
and right (bow steer).
BOTTOM
For maximum speed, a boat bottom should be
nearly a flat plane where it contacts the water and
particularly straight and smooth in fore-and-aft di-
rection.
1. Hook: Exists when bottom is concave in fore-
and-aft direction when viewed from the side.
When boat is planing, “hook” causes more lifton
bottom near transom and allows bow to drop,
thus greatly increasing wetted surface and re-
ducing boat speed. “Hook” frequently is caused
bysupportingboattoofaraheadoftransomwhile
hauling on a trailer or during storage.
2. Rocker: The reverse of hook and much less
common. “Rocker” exists if bottom is convex in
fore-and-aftdirectionwhenviewedfromtheside,
and boat has strong tendency to porpoise.
3. Surface Roughness: Moss, barnacles, etc., on
boat or corrosion of outboard’s gear housing in-
crease skin friction and cause speed loss. Clean
surfaces when necessary.
TRIM
TRIMMING OUTBOARD “OUT” (“UP”)
WARNING
Excessive trim “out” also may reduce the stabil-
ity of some high speed hulls. To correct instabili-
ty at high speed, reduce the power GRADUALLY
andtrim the outboard “in” slightly before resum-
ing high speed operation. (Rapid reduction in
power will cause a sudden change of steering
torque and may cause additional momentary
boat instability.)
1. Will lift bow of boat, generally increasing top
speed.
2. Transfers steering torque harder to left on single
outboardinstallationsbelow23in.(584mm)tran-
som height.
3. Increases clearance over submerged objects.
4. In excess, can cause porpoising and/or ventila-
tion.
5. If trimmed out beyond the water pickup,reduced
water supply can cause overheating resulting in
engine damage.
TRIMMING OUTBOARD “IN” (“DOWN”)
WARNING
Excessive speed at minimum trim “in” may
cause undesirable and/or unsafe steering condi-
tions. Each boat should be tested for handling
characteristics after any adjustment is made to
the angle (trim adjustment bolt relocation.)
1. Will help planing off, particularly with a heavy
load.
2. Usually improves ride in choppy water.
3. In excess, can cause boat to veer to the left or
right (bow steer).
4. Transfers steering torque harder to right (or less
to the left) on single outboard installations.
5. Improvesplaning speedacceleration (by moving
trim adjustment bolt one hole closer totransom).
WATER ABSORPTION
It is imperative that all through hull fasteners be
coatedwithaqualitymarinesealerattimeofinstalla-
tion. Water intrusion into the transom core and/or in-
ner hull will result in additional boat weight (reduced
boatperformance),hulldecayandeventualstructur-
al failure.
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