1997 OUTRAGE 20 Adding Trim Tabs

Optimizing the performance of Boston Whaler boats
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Joined: Tue Oct 20, 2015 3:10 pm

1997 OUTRAGE 20 Adding Trim Tabs

Postby Speedbump » Mon Mar 12, 2018 2:06 pm

I have re-powered my 1997 Outrage 20 with a new 2017 Evinrude E-TEC 150. I may add trim tabs to to help smooth the ride when the bay and seas get sloppy. I assume I should be looking at electric tabs rather than hydraulic operated trim tabs. I am unsure of the brand and size. I do have a transom mounted boarding platform and ladder on the port side and a transom mounted transducer just port of the center line. So rigging and mounting position for hinges and other attachments may be a problem. Any and all suggestions would be welcome. Thanks.--Graham

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Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula

Re: 1997 OUTRAGE 20 Adding Trim Tabs

Postby jimh » Mon Mar 12, 2018 4:00 pm

The REFERENCE section has an excellent article that discusses in detail with many illustrations the several possible methods for adding trim tabs to the hull of a classic Boston Whaler boat. I think your c.1997 20-foot hull will be different from the several examples shown, but you may find the various methods described to be useful. See

Trim Tab Installation

As for your assumption that you should or must or need to use trim tabs that are operated directly by electrical motors in preference to tabs operated by hydraulic pressure created by an external electrical motor, I don't know that the imperative you have ascribed to this really exists. Boaters use both types. I don't understand why your particular application would require one method instead of another.

I don't see how any suggestions about mounting that are specific to your hull can be offered until you post a good image showing the transom and the other gear already mounted on it.

The details you gave about the number of cylinders, the angle of the V6 design, the nature of of the fuel induction system, the propeller shape and number of blades, and other details of the engine will NOT have any influence on the mounting location for the trim tabs, and I elided that information from your initial posting.

General advice about trim tab location can be gleaned from my article (linked above) and from the installation instructions for the particular trim tabs you buy. Often you can get literature from the trim tab manufacturers before you buy the tabs. Consult this literature to get advice about details of the installation of specific tabs.

Manufacturers will also offer advice about the size of the tabs that are appropriate for your boat. Also, the farther from keel center-line the tabs are mounted the more effect they will have on lateral trim. As the article illustrates, the existence of boarding ladders and platforms already mounted to the transom will have a significant limiting effect on where you can install trim tabs. The composition of the transom and its reinforcements and their location will also affect trim tab installation by affecting where the ends of the actuators can be fastened.

You might also want to inquire with Boston Whaler to see if trim tabs were offered as an option on the 1997 OUTRAGE 20 hull; if tabs were available, then you may benefit from getting details about their mounting location from Boston Whaler.

I also offer this advice: before installing trim tabs you should assess the ride and handling characteristics of the boat with the new engine. I have found that trim tabs are very useful for leveling lateral trim, but are not absolutely necessary for adjusting the boat trim for best angle of attack into waves. Generally the engine trim provides enough fore-and-aft trim for the hull to produce the desired angle of attack into waves.