Bennett 189ATP 18 x 9 Hydraulic Trim Tabs with Auto Trim Pro

Trim Tab Sizing Guidelines

What size trim tab is right for me?
Many factors affect the choice of properly sized trim tabs, and the ultimate responsibility for selection is up to you, the boat owner. To help you decide, Bennett Marine offers you a few guidelines below. If you still have questions about the size you need, just contact us and we’ll be happy to walk you through it.

General Guidelines
These sizing recommendations are based on average performance. Your choice may vary based on power, engine configuration, weight distribution, type of boat, and use. The greater the surface area, angle of deflection and/or speed of the water flowing under the trim tab, the greater the lift.

When making a choice between trim tab sizes, remember that the largest trim tabs that will comfortably fit on the transom will be the most efficient.

As a rule, choose at least one inch of trim tab span (per side) for every foot of boat length. (Examples: 22-foot boat = no less than 24″ x 9″, 36-foot boat = no less than 36″ x 9″.

Span = side to side measurement
Chord = fore to aft measurement

Whenever possible, choose a 9″ chord trim tab, and gain lift through a longer span. The span of the trim tab has more of an effect on the amount of lift. However, a longer chord can be used effectively, and there are situations where you may need to use a 12″ chord. Click Here to See When to Use a 12″ Chord

Measuring
Choose the approximate tab size for your boat using this sizing chart. Make sure the tabs will fit your transom using the diagrams below as a guideline. When measuring, disregard the strakes and follow the Vee of the hull.

The sizing guidelines below are intended to assist in the selection of tab sizes for vessels that do not currently have tabs installed by the boat manufacturer. For assistance with unique applications not outlined below, please call us.

Boat Length	Trim Tab Size (span x chord)
15’-19’ (4.5-5.8 m)	8” x 10” (20 x 25 cm) M80
17’-19’ (5.2-5.8 m)	10” x 12” (25 x 30 cm) M120
19’-24’ (5.8-7.3 m)	12” x 9” (30 x 23 cm)
19’-24’ (5.8-7.3 m)	12” x 12” (30 x 30 cm)
20’-23’ (6.0-7.0 m)	18” x 9” (46 x 23 cm)
22’-27’ (6.7-8.3 m)	18” x 12” (46 x 30 cm)
22’-27’ (6.7-8.3 m)	24” x 9” (61 x 23 cm)
25’-31’ (7.6-9.1 m)	24” x 12” (61 x 30 cm)
25’-31’ (7.6-9.1 m)	30” x 9” (76 x 23 cm)
25’-31’ (7.6-9.1 m)	30” x 12” (76 x 30 cm)
32’-38’ (9.7-11.6 m)	36” x 9” (91 x 23 cm)
32’-38’ (9.7-11.6 m)	36” x 12” (91 x 30 cm)
36’-44’ (11.0-13.4 m)	42” x 9” (107 x 20 cm)
36’-44’ (11.0-13.4 m)	42” x 12” (107 x 30 cm)
42’-50’ (12.8-15.2 m)	54” x 9” (137 x 23 cm)

Why do I need Trim Tabs?

You may not be familiar with them, but you’ve probably experienced the problems that trim tabs solve for boaters all over the world. After using Bennett systems for years – and discovering just how durable and serviceable they can be – our customers can’t imagine boating without them.

Do These Conditions Sound Familiar?

As your boat slows from maximum speed, it begins to settle at the stern or “squat,” creating an inefficient, untrimmed condition. At this attitude you use more fuel to drive the boat.

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. Also because of significant hull drag and extreme prop angle, fuel economy is poor.

Uneven weight distribution makes your boat harder to handle, even harder to get up on plane, and it causes your boat to list to one side. Your passengers complain when you tell them to move from one side to the other.

As a boater you know that no two boating days are ever alike thanks to ever-changing weight, weather and water conditions. Bennett Trim Tabs are designed to adjust for these changing conditions and provide lift in order to give you the best possible running attitude.

Get the Best Ride Possible

Bennett Trim Tabs help your boat operate as intended over a broader range of conditions. They give you more control than you ever had before. You can improve the performance of your boat through properly sized trim tabs that:

• Get you up on plane quickly
• Allow you to plane at speeds lower than designed planing speed
• Adjust the boat’s attitude for changes in speed, sea conditions and shifting weight
• Correct listing on either side of the boat

Bennett Trim Tabs reposition the boat’s bow to cut through the water. This gives you several advantages:

• Less drag and engine laboring, which translate into increased performance, greater speed, and reduced fuel consumption
• Reduced pounding, which means greater comfort
• Greater visibility, which increases safety
  

Bennett Trim Tabs help your boat operate as intended over a broader range of conditions. They give you more control than you ever had before. You can improve the performance of your boat through properly sized trim tabs that:

• Get you up on plane quickly
• Allow you to plane at speeds lower than designed planing speed
• Adjust the boat’s attitude for changes in speed, sea conditions and shifting weight
• Correct listing on either side of the boat

Bennett Trim Tabs reposition the boat’s bow to cut through the water. This gives you several advantages:

• Less drag and engine laboring, which translate into increased performance, greater speed, and reduced fuel consumption
  Reduced pounding, which means greater comfort
  Greater visibility, which increases safety

Did We Mention Savings on Fuel?

Maintaining plane at a lower RPM is where the boat starts to achieve its maximum efficiency. Trim tabs provide the additional lift so that the throttle can be decreased without losing plane, adding both fuel economy and range. Some boaters have experienced as much as 30% fuel efficiency gains.

With all the advantages and efficiencies created, Bennett Trim Tabs virtually pay for themselves.

The Bennett Advantage

Performance:
Turn a teeth-jarring experience into a more comfortable ride.

• Increase Speed
• Reduce Pounding
• Correct for Listing
• Eliminate Porpoising
• Offset Prop Torque

Efficiency:
Bennett Trim Tabs are one of the few boat accessories that can pay for themselves. Some boaters have experienced as much as 30% fuel efficiency gains.

• Reduce Fuel Consumption
• Reduce Engine Laboring
• Eliminate Squatting
• Reduce Engine Laboring

Safety:
Relax at the wheel thanks to greater control over your bow high position.

• Improve Visibility
• Reduce Wake
• Improve Handling
• Reduce Hull Stress