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 well be happy
to walk you through it.
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
Chord = fore to aft
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.
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.