Trim Tabs

[Maui]

I have a 1982 Californian 38 with twin 3208T caterpillar’s. At 2700 RPM I’m cruising at 17 kts. Planing. I’m burning 18 gal per hour for both engines. The bow is up a bit. Would trim tabs help my trim and fuel usage to make the expense worthwhile? What size tabs would I need?

 

[Dougcole]

I bet they would. They would also help you get on plane faster or at least level out faster.

 

[Keysdisease]

Boats are designed to ride on an even keel at a specific bow up attitude, that's where they will plane most efficiently. Trim Tabs will allow you to achieve whatever attitude is called for in any given condition. Spray coming up off the port bow with wind on the beam, put the port bow down a little to knock it down. Ice melts, fish come aboard, refreshing beverages get consumed, the wind on the beam puts her on her ear, all can be corrected with trim tabs "on the fly."

As Doug mentioned, they will help you get on plane faster and smoother and stay on plane at slower speed. If you are looking to extend range on plane being able to stay on plane at a lower speed will do that and tabs will be paying for themselves.

Just like with airplanes, the faster you go the less "wing" you need. Our "slower" boats call for a little more than the common rule of thumb which is 1" if tab width for each ft of boat length. I have 42" x 12" on my 200HP 34 Mainship, need every inch to wallow up onto plane.

I recommend Bennett for too many reasons to list. The 42 x 12 is the largest they make standard with one actuator. Starting at 48 x 12 they are all dual actuator

 

[jleonard]

I ask one installed 42 x. 12 tabs on the 34 Mainship I used to own.
In addition to what Keys stated above I could get the boat "on plane" at 7 knots.
They also help reduce roll at anchor.
They will be a nice addition to your boat

 

[DavidM]

The real question is: Without trim tabs is the attitude (degree of bow up) the most efficient, ie is your speed as high as it is going to get at your cruising rpm.

For many boats it is not and trim tabs drop the bow allowing for a more efficient attitude and slightly more speed.

And in general if you need them, you probably need as much area as can be easily installed on your boat.


David

 

[Maui]

Thank you for the insightful feedback. I plan to short haul my boat in July and I’ll install the set then.