Attitude Adjustment: Trim Tabs 101

Grady-White installs Bennett Marine hydraulic trim tabs, thanks to their reliability in adding to a great boating experience. Learn about trim tabs and polish your “attitude adjustment” skills! Here are the basics.

What they do
Trim tabs are used to correct for pitch of the boat or side-to-side heel, to add lift at the stern when getting on plane, and to lower the bow once on plane. They have no effect at low speed, roughly defined as below 10 knots. They have increasing effect as speed increases.

How they work
Trim tabs are controlled by two rocker switches that are individually wired so that the port switch controls the starboard side tab, and the starboard switch controls the port tab. For example, when you push the port rocker switch forward, the starboard tab lowers and the port bow goes down. Switches are labeled “bow up” and “bow down” to make the tabs more intuitive to use. Indicator lights show the angle of the tabs: the more lit, the greater the angle. At high boat speed, excessive tabs down can result in the boat bow-steering which means less control and efficiency. Watch video “Troubleshooting trim tabs.”

How to use them
Usually you will want to lower both tabs all or most of the way to help the boat get on plane faster with less bow rise; then, as you gain speed, start raising them again most or all of the way. Customer Tips has more. 

Engine trim and tab trim
Engines are trimmed to adjust the boat’s trim, or bow rise, to minimize resistance and maximize speed. Tabs are used to (1) get the boat on plane more quickly, (2) allow it to stay on plane at lower speeds, and (3) correct for heel to one side. Grady-Whites’ trim tabs automatically return to the fully retracted position when the engines are shut off. 

See more on trim tabs at our FAQ area and Customer Tips area.