intentions to allow them time to make adjustments to
their balance or positions.
and quartering seas. Trimming your boat properly
involves two separate procedures, trimming or tilting
the lower unit (stern drives) and setting the trim tabs.
Slowly pull back on throttles, glance back and see if a
large following wave is approaching the transom. If so
give the engines a little throttle as the wave arrives to
keep wave from rolling over the transom.
When you are sitting dead in the water, your drive
should be down and the trim tab switches are in the
BOW UP position. Accelerate until you get onto
plane. At this point your boat will be plowing through
the water with the bow down too far. Trim the lower
unit up slightly until the bow comes up. If you trim the
lower unit out too far, your boat will porpoise or the
propeller will cavitate, and the bow will slam up and
down on the water. Your boat is trimmed correctly
when it is just short of porpoising or propeller cavita-
tion, under ideal running conditions.
Once you have spent enough time practicing maneu-
vers and have a feel for how the boat handles, you will
be ready to run in open waters.
S - 6
Trim your boat to compensate for seas, winds, or
Before accelerating to bring you boat on plane,
be sure that the area in front of your boat is
clear. The bow will rise out of the water
momentarily before you plane and may
temporarily obstruct your vision.
Trim drives in more than
usual. Use tabs to keep
bow down and go at a
If you have never had your boat on plane before,
choose a calm day for your ﬁrst on plane experience.
Never boat beyond your ability and experience.
To prevent taking seawater
The bow, trim drives out and
keep tabs up to keep bow
Before bringing your boat “on plane”, check the entire
area to make sure you have a clear, safe path. As you
throttle up to accelerate, your boat will increase its
angle of trim, causing the bow to ride high. From a
maximum angle, the boat will level out to its planing
attitude with continued acceleration. This maximum
angle is known as the “hump”. Because visibility,
handling, and performance are reduced, it is advisable
to get “over the hump” as soon as possible. A few
seconds at full throttle should get the boat over the
hump and into its planing attitude.
Listing Due to
Beam Wind, or
Use tabs independently to
adjust for list. If listing to star-
board, press port bow down
switch. If listing to port, press
starboard bow down switch.
Remember that most boats react very slowly to trim
tabs. Often boat owners do not give trim tabs time to
work. Press the trim tab switches for only one second
at a time and then allow some time for the boat to
react. If the boat is still listing after a minute or two,
press the trim tab switch again for a one second
interval. The labels on the trim tab switches indicate
what you want your boat to do, not what you want the
tabs to do.
After getting over the hump, accelerate until reaching a
comfortable plane, then throttle down to cruising speed.
This also will provide for better fuel efﬁciency.
S - 7 TRIMMING YOUR BOAT
A. Trim Tabs
It is a good idea to take your boat out onto open
water shortly after you get it and experiment with the
trim tabs. After you get your boat onto plane, set the
tabs in various positions and note how your boat
reacts. This will give you a feel for how the trim tabs
Trim tabs are used to add lift to the boat’s stern,
thereby changing the boat’s attitude (see Figure S1).
This lift can help the boat get on plane faster and
remain on plane at slower speeds than if no tabs were
used. Used independently, tabs can also correct listing
conditions caused by crosswinds, unbalanced loading
It is possible to extend the cylinder life expectancy on
your trim tabs. To do this, keep the cylinders retract-
Pre-Launch and Underway - Section S
Owner’s Manual Page 181
|Categories||Four Winns Manuals, Four Winns Vista Manuals, Outboard Marine Corporation Manuals|
|Tags||Four Winns Vista 338|
|Model Year||2007, 2008|
|Document Type||Owner's Manual|
|Product Brand||Boats and Cruisers, Four Winns. For support contact your dealer at http://www.fourwinns.com/locate-dealer.aspx|
|Document File Type|
|Wikipedia's Page||Outboard Marine Corporation|
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