A new trim tab system

[bostonhatteras]

Now that I've come to the conclusion that the existing antiquated tab system is not repairable, I have to choose a new system. The boat currently has the insta/trim style wiring to helms along with insta/trim rocker switches that are relatively new. Of course she has the pocketed fiberglass trim tabs along with new hinges and through bolts I put in when I did the epoxy bottom. One thing I don't have is a transom recess where most Hatt boats locate the hydraulic actuator, it's just smooth across the entire transom. I'm thinking it's not worth it to fill the existing trim tab pocket in order to install the Humphree style tabs, although they are modern and likely better performing than old school tabs. Sticking with insta/trim, Id need to drill two new holes to have tab position indicators, at least Bennet has the indicator lights in the switch...swappable? If I go with insta/trim, I will need to modify/lengthen in the horizontal plane the aft vertical surface of the tabs to be able to mount the actuator. Ill likely need to make a mounting block on the transom for the actuators upper mount as well. Those mods to install insta/trim components are pretty easy. Going Humphree I'd need to eliminate the tab pocket and fill/glass the area. Not sure how that would leave me mounting options for the Humphree tabs, since the first place a bolt could go through to get a nut on the other end would be over 3" up or more from the running surface. the Humphree is relatively self contained and the insta/trim has parts and hoses all over. looked at another way, the insta/trim is damn reliable and easily repaired and the humphree is an unknown to me. I'm definitely leaning insta/trim but if anyone has any opinions to sway me in other directions have at it.

 

[SKYCHENEY]

What about keeping part of your old system and modifying it to accept a couple of Bennett cylinders? Keep the arms going through the hull and add the rams inside the hull to push those arms up and down. Just a thought.

 

[bostonhatteras]

That is a good thought. When I was attempting to remove the right angle drive, I found I could move ALL visible tubes associated with the acme screw assembly. The tubes didn't move easily but they did move. Was this entire assembly installed into another larger tube glassed cleanly and neatly at the hole going out? I can't tell that without some invasive surgery. The tubes I can see are held by one layer of woven roving to the transom, that's not a lot of structure. Poking my finger inside the rod hole going out to the tab I can feel a smooth wall tube that appears to be joined to the hull. Ill bring an inspection camera and look inside the hole a bit deeper. The acme thread of the old system must be attached to the tab rod via a ball and socket which I can't see, this assembly would need to be modified. The tab rod must be sealed and stabilized now as the entire acme screw assembly is below the water line.