WHAT TRIM TABS DO

Most
boats are designed to plane at a particular speed and weight
distribution. However, as weight increases (due to additional fuel,
passengers, or gear) and/or speed decreases, the stern settles
down creating an inefficient, untrimmed condition. As the boat
pushes forward, it creates a "hill of water." In this bow-high position visibility
is limited and the hull bottom is pounded. In addition, due to significant
hull drag and extreme prop angle, fuel economy is poor. Properly
sized Bennett Trim Tabs enable your boat to overcome this "hill" and
plane at speeds slower than designed planing speed.
As the helm control is pressed, the stern rises, lowering the
bow. Without touching the throttle, speed increases and optimum
attitude is achieved regardless of speed or weight distribution.
Bennett Trim Tabs reposition the boat's bow to cut through
the water reducing pounding, drag, and engine laboring. Repositioning
the bow creates greater visibility which increases safety.
Reduced pounding means greater comfort. Less drag and engine
laboring translate into increased performance, greater speed,
and reduced fuel consumption.
With all the advantages and efficiencies created, Bennett Trim
Tabs virtually pay for themselves.
THE PRINCIPLE OF BENNETT
TRIM TABS
Bennett Trim Tabs are two independent, stainless steel, adjustable
afterplanes attached to the bottom edge of the transom. As the helm control is pressed,
the trim tabs move into position.
Water-force on the trim tab surface creates upward pressure, thereby raising the stern and
lowering the bow. The principle is simple. The results are impressive.
THE
BENNETT ADVANTAGES
Performance
Increase Speed Reduce Pounding Correct Listing
Eliminate Porpoising Offset Prop Torque
Efficiency
Reduce Fuel Consumption Reduce Engine Laboring Eliminate
Squatting
Safety
Improve Visibility Reduce Wake Improve Handling Reduce
Hull Stress
How to Use Trim Tabs
GETTING STARTED
The key to obtaining optimal results from trim tabs is to operate
them in short "bursts" and let the boat react before making
another adjustment. The amount of time between corrections
is influenced by the size of the trim tabs and the boat's speed.
This will help avoid overtrimming or ending up with one tab
too far down when correcting lateral trim. You will quickly
become acquainted with a boat's particular traits.
TAKE OFF 
Properly sized trim tabs can significantly reduce the
time needed to get up on plane. They also allow a boat to keep its bow down
and stay on plane at lower speeds. As the throttle is advanced the stern
of the boat begins to squat, lifting the bow. As the boat accelerates, push
the bow down position of the helm control in short bursts. The boat reacts
by the stern lifting, the bow coming down, speed increasing, and reduced
engine laboring. If you over do it and deflect the tabs too far the boat
will end up overtrimmed. When over trimmed, the steering becomes over
sensitive and wants to pull off course to port or starboard. If this occurs, operate
the control bow up" until the desired attitude is established.
CORRECTING A LISTING CONDITION 
As a result of uneven weight distribution, prop torque or wind, a boat
runs with a list. Deep "V" hulls are particularly vulnerable to this condition.
Running with a list is uncomfortable, as well as unsafe. Bennett Trim Tabs operate
independently for effective list correction. To correct for list, lower the trim tab
on the side of the boat that you are listing to. This will bring the
boat level.
TRIM
TABS AND POWER TRIM
It is a common misconception that if a boat has power trim on
the outboard or outdrive it does not need trim tabs. Power
trim can be used to adjust the boat's attitude, but it is highly
inefficient. A propeller
is designed to force the boat forward. When trimming the boat with
the prop, the prop must not only push the boat forward but raise the
stern as well. In this situation, prop slippage is greatly increased
thereby wasting RPM's. Power trim cannot correct listing, and is ineffective
at slower speeds. Bennett Trim Tabs, in combination with power
trim, enable both the hull and prop to be trimmed independently.
The trim tabs trim the hull, while the power trim adjusts the prop.
The result is optimum performance and efficiency not attainable by
the use of power trim alone .
To achieve maximum performance, first adjust the
trim tabs to achieve the desired running attitude. Next, use the
power trim to position the propeller thrust parallel to the water
flow. If necessary, re-adjust the trim tabs to fine tune the attitude.
By observing the boat's speed and engine RPM's the best combination
of trim tabs and power trim will be apparent. Trim tab angle indicators
and a power trim angle indicator are particularly useful in duplicating
effective settings.


TRIMMING TO SEA CONDITIONS
When running into a head sea you want to trim the bow down so the sharp
forward sections of the boat do their work cleaving the waves. This provides
the most comfortable ride and minimizes stress on the boat (and passengers).
In a following sea the tabs should be fully retracted for maximum steering
response .
CORRECTION OF PORPOISING
Operate the tabs in very short bursts of about half a second. Continue
until porpoising subsides. The objective is to have only a very slight
amount of tab deflection, just the amount needed to cure the up and
down motion of the bow.