Bad Trim Tab design or bad luck?

[GaylesFaerie]

Hi, I purchased a 2012 R27 a few months ago and just hauled out for the winter. Upon inspecting the trim tabs I was shocked. Both anodes were completly gone and on the starboard one, the bracket for the actuator separated from the tab. I don't know how these tabs are fabricated/designed but at first blush is looks like the anode is supposed to provide support for the through bolts holding the bracket onto the tab (I'm no engineer but having a part designed to erode away while providing support for another part seems wrong). If so, once the anode is gone poof! the bolt nuts have nothing to bind against and support them. Or is this just a coincidence and the actuator bracket is welded to the tab and the welds broke?

Pictures:

Port tab with zinc gone but bracket intact: https://photos.app.goo.gl/b8uDrQnE5cEdC1CZA

Starboard tab stern view of loose bolts: https://photos.app.goo.gl/yUheqzgaXN45c68E6

Starboard tab forward view of separated bracket: https://photos.app.goo.gl/Qp9c7KH3wsSe1jfk6

And any advice for removing all the old paint?

 

[CAPTCRUNCH]

I don't think Bennett designed it that way. Pretty sure there's supposed to be a less-sacrificial ferrule or collar (?correct term?) cast into the anodes for the bolts to pull against. I think there's one visible in your first photo. Curious that it remains and the other three are gone.

 

[Brian B]

The bolts hold the actuator to the tab, with the zinc deteriorated the actuator is loose. I don't see a broken weld. The actuator brackets are plastic. How old were the zincs? On my boat I installed round zincs in the center of the tabs, they usually last a couple of years.

 

[Red Raven]

On my 2014 R27 the anodes are not mounted in that way. Round clamshells on the main part of the trim tab. They are at 50% at 6 months in the PNW when I replace them. Seems it would be simple to replace the bolts for the actuator mount with shorter ones and add the clamshell anodes to the tabs. Be sure to remove all the corrosion and anti fouling paint from the area where the anodes are mounted to make good contact with the metal.

 

[ALICE J]

I replace my zincs about every six months. 😳 Buy be very wary of the magnesium anodes for freshwater, then accidentally put them into saltwater, 😳 Gone in maybe three weeks with strange calcium like buildup on the anode, coating the ss bolts and nearby areas with a think coating. I was on the Kentucky Lakes this fall and had aluminum anodes, which worked fine, but when I place my boat R27 2011 into saltwater for less than a week, tiny pinhead eruptions (about 1/8 to 3/16" diameter) were on the face of the anodes that sluffed off when touched while wet and powdered when dry. I am now back to zinc anodes for saltwater. :roll:

 

[HRowland]

Hi Gary, when I originally bought your boat the dealer arranged for bottom painting since it was a brand new boat. S&S Marine in Old Saybrook CT did the work, they are down the CT river from the selling dealer in Essex. They installed Bennet trim tab zincs that included longer screws to replace the original short tab to activator screws. The problem is these actuator hinge brackets are plastic and eventually can strip out, after a few years I had to start using a through bolt and nut like you see. I also found that if I painted the tabs with 2 coats of epoxy primer (Interprotect) then bottom paint the zincs would last for the season, I believe this is due to less stainless steel in contact with sea water reducing erosion rate of the zinc. Note I always made sure the area in contact with the zinc was clean.
These are the zincs I used, they are the same as installed, these are the same as used by S&S Marine.

https://www.boatzincs.com/bennett-trim- ... e-kit.html

Howard

 

[GaylesFaerie]

Thanks everyone. I think my solution here involves a number of steps: first strip these trim tabs down to bare metal (they are in a very sorry state), second is to bolt the actuator mount directly to the tab without using the stock anodes, third is to get and install clam shell anodes directly on to the tabs, and finally prep all the metal (except anodes) for primer and bottom paint. Design-wise I'm still scratching my head about plastic actuator mounts with screws on equipment that seems like it takes quite a load. Thanks again, GF

 

[Levitation]

Interesting. I wonder if a conversation with Bennet might be more enlightening than opinions here. :mrgreen:
On my tabs I drilled and bolted a zinc to the topside of the tab.
I also hang a fish off the stern when at the dock.
Painting the tab with a bottom paint containing metal then bolting a zinc or aluminum anode to the tab seems counterproductive.

 

[CAPTCRUNCH]

https://bennetttrimtabs.com/guide-to-tr ... 3dfe3-4e9a
(954)-427-1400

 

[BB marine]

Yes the trim tab actuator brackets are composite with 1/4 20 threads. The screws used are stainless 304 the same has the planes. The threads and brackets hold up well has long has there is not a impact to them and they are not cross threaded. The other way the threads are damaged is when unthreading them you must clean the protruding threads of corrosion, marine growth, dirt. The producing threads are use to hold the trim cylinder/ bracket pin in place so it will have 1/2' of exposed thread that need to be cleaned. If the anodes that are used in the thread (GaylesFaerie) are continued to be used I would recommend a different way of installing them.

I would first replace the hinge brackets (they are replacement parts.) With new undamaged threads install the mounting brackets to the trim cylinders. Purchase stainless steel 1/4 20 threaded rod. Measure for proper length. 1/2" protruding past the mounting bracket + thickness of bracket+ thickness of anode + thickness of( 2 ) 1/4 20 nuts.

Thread the threaded rod through the plane holes and into the trim cylinder bracket until the thread engagement is far enough to stop the bracket to cylinder anchor pin from sliding out. Thread a 1/4 20 nut onto the threaded rod tighten it. This is holding the trim cylinder to trim plane. Now install the anode onto the threaded rods. Place a couple of drops of red locktite on the threads a SS flat washer and then install the nut. tighten the nut. Thhis nut holds the anode in place. If the anode is sacrificed the trim ram will still be tight to the plane.

I use a 3" rudder anode bolted to the plane. I have my planes painted. When I painted them I used the anode as a template to mark the area not to be painted. When I replace the anodes I sand the area of contact to polish the Stainless surface to ensure good continuity between the anode and the plane.

Painting the tab with a bottom paint containing metal then bolting a zinc or aluminum anode to the tab seems counterproductive.

If you paint the planes with bottom paint you need to first paint the planes first with a barrier coat. then apply the bottom paint. As long as the anode is touching clean metal it will protect the plane it is attached to. (only)