Bennett Trim Tab Installation

C-Sick · Posted: Sat Apr 29, 2006 11:50 pm Post subject: Electrical Connection

What is the recommended method to connect the M120 to the electrical source. Do you go off the bus bar or go directly to the battery?

C-WEED · Posted: Sun Apr 30, 2006 8:16 pm Post subject:

The main hot lead is fused with a 20 amp fuse. The instructions say to attach to 12 volt supply. I had a spare slot on the bus bar and went that route. With the battery switched off the system is dead as I would want it to be. Normally you wouldn't need to operate the tabs without the engine running. (or battery switched on)

If you opt for the auto-retract box: It's 12 volt supply can be anything that is hot with the ignition key "on". Two easy sources are the engine trim indicator or the hour meter. This gadget pulls the tabs all the way up when the engine is switched off. Handy for beaching or getting ready to trailer out.

C-WEED · Posted: Sun Apr 30, 2006 8:47 pm Post subject:

Jimbo: My starboard tab hydro tube is 46.5 inches shorter than the port tube. Port tube is stock length. Since they run independant of one another I didn't think it a big deal when I cut it. I think the factory is after getting both tabs to run at the same speed. IE: When you bump both tabs down to lower the bow. The shorter tube might run that tab down slightly faster than the longer tube perhaps cuasing a list. Not very scientific but I just ran mine down together and couldn't SEE any difference. The auto retract sucks them both up also. I just installed my new kicker mount today. Still have to hang the motor but hopefully it will solve the kicker vs. tab clearance. Then maybe I'll try the tabs for the first time next weekend. Weather forecast is thunderstorms Crying or Very sad

ksidener · Posted: Tue Jul 31, 2007 5:31 pm Post subject: Trim Tab Installation

Sorry for this dumb question, but better to ask and understand than not ask and stay in the dark. Am I safe in assuming the transom has enough solid wood (or plywood) not balsa core to mount the tabs with simple wood screws? I have watched the Bennet installation video and that appears to be all they are using for another brand boat.

Do we have to do the relief hole filled with epoxy to mount the trim tabs?

Much appreciated in advance.

Kelly

Papillon · Posted: Tue Jul 31, 2007 6:09 pm Post subject:

I used the SS screws provided and put some sealant on them before screwing in to the pre drilled pilot holes and have not had them fall off yet. I do believe that where you are placing the tabs is pretty solid.

Good Luck, You will not regret getting the trim tabs.

drjohn71a · Posted: Tue Jul 31, 2007 6:18 pm Post subject:

Kelly,
While marine plywood (if that is what C-Dory is using there now) is stronger than balsa core for screw placement, the ply orientation of the plywood makes for more catastrophic damage since the water leaks parallel to the plys and will encompass a large area of the transom before being detected.

I really think it's not too much trouble to put some epoxy liner in those holes considering the possible consequences of not doing so.

Just another opinion,

John

ksidener · Posted: Wed Aug 01, 2007 4:23 pm Post subject: Trim Tab Installation

Thanks John and Papillon for your input. I have had a process described to me that involves drilling a pilot hole then doing a relief cut in the core that leaves the outside fibreglass in place. One would then fill the hole with fast cure epoxy and then drill the epoxy to install the screw. I guess that is the safest solution, but unsure of it's strength.

Kelly

drjohn71a · Posted: Wed Aug 01, 2007 4:28 pm Post subject:

Kelly,

I think the epoxy plug technique is very important for a submerged part. You can get or mix some type of filler spheres to make the epoxy easier to screw into. Dr. Bob of Thataway is kind of an expert on that as well as others here.

Looking at the photos of the water damage to the plywood in the last CD25 that Dr.Bob fixed up shows how a small leak can spread way out.

As far as the stregth goes, there is nothing stronger to my knowledge. Much stronger than just setting screws in plywood. You might call a marine supplier to ask if it would be easier to screw into a "filled" epoxy - one with softer spheres mixed in to allow easier screw penetration.

John

tsturm · Posted: Tue Aug 14, 2007 11:49 pm Post subject:

The 9 X 12 Bennett Trim Tabs made a whole new boat out of the JMR II. No more smack smack smack when running in a 1-2 foot chop! Mr. Green

mikeporterinmd · Posted: Wed Aug 15, 2007 2:10 pm Post subject:

Ain't that the truth. The other thing I've found is that milage increases
with the tabs down. Always a plus when a more comfortable ride is
efficient as well.

Mike