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Trim
To Perfection (20-2)
by Dusty Miller
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 The
balance between speed and hull attitude is a vital element
of control. We have all seen boats racing down the lake
at full throttle, throwing a huge bow wave with the
hull flat on the water. At other times we have seen
boats cruising with the bow way up and out of the water.
The problem in both cases is improper hull attitude,
which is a contributing factor to the loss of performance,
fuel economy and handling ability. However, it’s
a problem that’s quite easy to understand and
fix by using proper trim and speed.
Trim tabs are large, flat pieces of stainless steel
attached to the leading edge of the transom on a hinge
and secured with a hydraulic ram. The tabs are controlled
by a set of toggle switches at the helm. Toggling the
tabs up brings the tab up flat against the hull, while
toggling down pushes it away from the hull. The trim
tabs act like elevators on an aircraft and tilt the
bow up or down to correct attitude problems.
The trim adjustment for I/Os or outboard engines is
on the throttle handgrip where your thumb rests. Moving
the switch up swings the drive away from the hull, raising
the prop higher in the water. Adjusting it down brings
it closer to the transom. Remember the default position
is all the way down for I/Os and outboards and all the
way up for trim tabs.
Correct trim helps the boat get on plane and remain
there at lower speeds. When the boat rides low in the
water at the stern, lowering the trim tabs will help
raise the hull on plane and keep it there. You’ll
feel the difference in the time and effort it takes
to get on plane and the speed of the craft once it’s
on plane. If you apply the tabs too much, they can force
the bow down, slowing the boat and decreasing efficiency.
Again you have to find the right balance.
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(Read full article in the magazine.) |
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