How to Adjust Trim Tabs on a Boat

Trim tabs are a great way to adjust the attitude of your boat in the water. They can help control the pitch of your boat — its angle from bow to stern— but can also be used to compensate for weight imbalances along the roll axis from port to starboard.

Understanding How Trim Tabs Work on a Boat

Trim tabs extend the planing surface underneath your boat. Because they can both be moved up and down, they allow you to essentially re-shape the trailing edge of your boat to meet your needs. Trim tabs can be used to lift one side of the boat or the other to correct a list or protect your boat from waves. They can also help pitch the bow downward in situations where it might improve the ride.

How to Operate Boat Trim Tabs

It’s easier with tab position indicators, but if you don’t have them, there’s a workaround. Generally, the left-side trim tab switch controls the right-side tab and vice versa. To lower the port tab, press down on the right-hand switch; to lower the starboard tab, press down on the left-hand switch. When you’re not using them, you want to keep them in the neutral position.

To do this, start with your boat on the trailer. Use a straight edge along the bottom of your boat to find the neutral position on the trim tabs. This is where they extend the planing surface on your boat. On the indicators, mark this position with a white or red marker, or something else you can see.

If you don’t have indicators, lift the trim tabs all the way up, then use the trim tab control to count how many seconds it takes to get back to neutral. Now you can always get everything reset by lifting the tabs all the way up and then counting them back down.

From neutral, the process gets easier. To lower the bow, pitch both tabs equally below neutral. This raises the stern and pushes the bow down. To pick the bow up, lower the stern by moving both tabs equally above neutral.

How to Adjust Trim Tabs for a Listing Boat

When you’re trying to change the up and down pitch of the bow, you’ll use the trim tabs together. But the reason they’re on independent adjustment switches is so you can move them individually in order to account for a listing boat, either from waves or an uneven weight distribution onboard.

If your boat is listing to port, press down on the right-hand trim tab controller to lower the port-side tab and lift that side of the boat. You can also fine tune this with a little bit of up on the starboard tab, controlled by the left-hand control switch. 

If your boat is listing to starboard, just inverse the process. The point is whatever side you’re listing to, you can use the tab on that side to add lift to the planing surface in order to compensate.