Trojan Boat Forum

Trojan trim tabs were primarily for transverse stability. ( port and starboard balance)

On Trojan F boats optimal planing is at 4 degrees from bottom water surface. (Bow up )

On Trojan Internationals planing is 5 1/2 degrees (runs up hill)

On smaller F boats F-25 and F-26 (single screw) slow spreed planing can be achieved with more tabs.

You can check degrees with a Inclinometer


We have all the parts for Trojan original trim tab systems.
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Would there be any advantage to drop fin tabs on my '87 F32? I could not find a thread on the F series boats.

here's a post from 2008

what a valuable asset this FORUM is

viewtopic.php?f=1&t=856&p=3839&hilit=drop+fin+rws#p3839

RWS

This forum is a great resource indeed! I was wondering if anybody had added drop fins to their F series. If so,what were their impressions.

This forum is a great resource indeed! I was wondering if anybody had added drop fins to their F series. If so,what were their impressions. I could not find this during my search. perhaps no one has.

Many F32s had trim tabs installed as a factory option. OEM equipment was Insta-Trim http://insta-trim.com/ but I think Bennett may be on more boats https://bennetttrimtabs.com/ .

My F32 has the Insta-Trim, and on my father's old 1969 28' Sea Skiff we installed a Bennett system.

If you plan to run on plane then tabs are almost a must have (assisting with lateral stability, able to level the boat out if you have more weight on one side or strong cross wind, and helping fine-tune running angle for more efficient running and adaptability to sea conditions). If you only intend to plod along at 1500rpm / 8 knots or less, then they won't do much for you.

dab62 wrote: ↑Fri Apr 02, 2021 3:18 pm This forum is a great resource indeed! I was wondering if anybody had added drop fins to their F series. If so,what were their impressions. I could not find this during my search. perhaps no one has.

I suspect you're talking about an interceptor or vertical plate trim systems. They're a good system and work great, better than regular tabs IMO. A lot of high end boats use them. They had their issues when they first came out but improvements have been made since. They deploy and retract much faster (about 5 times) than regular tabs, and while they create less drag than regular tabs, they provide more lift. There are simple up/down systems, or more complicated units that provide options like gyros for auto leveling, automatic roll control, stabilization, programmability, etc. They basically operate on the same principle as regular tab units, they just do it a different way, except that the interceptor design doesn't require the unit to be that far into the stream of water, only about an inch or so for full deployment depending on the model.

Interceptors are great for deep sea sports fishing rigs that use reverse quite often. With regular tabs, you need the optional brackets to keep them from getting ripped off in reverse at higher rpms due to the pressure of the water pushing down on them. They're not made to be used that way without the optional brackets which prevent the actuator from being extended beyond its working limits. That isn't a concern with interceptors.

As always, there's pros and cons to both systems. Bennett hydraulic tabs for example can operate trouble free for decades with perhaps the odd actuator seal replacement. Same with Insta-Trim as long as the critters don't chew on the exposed hydraulic lines. Those lines are also exposed to the elements and tend to need replacing after a while as the rubber ages. As internal working on most interceptors are exposed to the water they're in, they can get fouled up with marine growth but I have found that it happens more often in units that aren't used much.

Check out Zipwake at https://www.imtra.com/learning-center/categoryid/15