Trim tabs installation

[corsara]

Hello. I need some help regarding installing trim tabs to a fiberglass hull I got. Since I don't know much just yet, excuse me if I my questions are dumb.

Question 1: With the trim tabs set, they included bolts, as well as screws. Since the hull is made of fiberglass with a wooden piece on the inside to make the transom tougher, which ones should I use---the bolts or the screws? If it's the screws, should I pre-drill pilot holes?

Question 2: Do I need to seal the bolts/screws somehow so water doesn't get inside, or that's not really necessary?

Question 3: I already know the tabs should not be flush with the bottom (about 1mm-2mm as advised by a fellow member in my other thread), but how far from the keel should they be? I'm interested in straight-line performance.

Here are some pics of the hardware I have, along with test-fitting the tabs with the help of electrical tape.

[Luck as a Constant]

1. Forget the wood screws and use bolts with a washer and nut on the inside.

2. I have never need to seal a hole, I drill the holes very close tolerance to the bolt, but if you must, plumbers putty is the best to use.

3. About 3/4-1" from keel should work.


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[tlandauer]

I use this when ever I drill on the hull: http://www.offshoreelectrics.com/pro...od=dh-gpmr8130, I learned about this tool because of Properchopper---he was nice enough to initiate a total newbie when I started my first build!

[Chilli]

Screws will eventually loosen up or strip the wood. Use bolts or blind nuts. Nuts and bolts will also loosen due to vibration so use a thread lock.
My preference...I always bed down my hardware with silicone or 3M 5200. 5200 takes a while to cure but once it does, your hardware will never move.
You don't have to put your tabs too close to the keel to be effective in the straights. We were talking to John Finch about this last fall. If it was me, I would slide the tabs out a bit further but it's always best to let us know what hull your are running so someone with a similar set up can tell you definitively what works.

[corsara]

Alright folks, I drilled, dipped the bolts in silicone, installed. See pics for the result. I didn't make them flush, they're about 2mm from the bottom. The plate has elongated holes, so I can loosen it up and push them down a bit..should I?

1-2014-05-07 23.47.25.jpg

2-2014-05-07 23.47.37.jpg

[tlandauer]

Yes!
Looks great though!

[corsara]

Yes!
Looks great though!

Thanks! Ok, I'll make it a little bit more flush with the bottom, maybe just a notch from the bottom I guess.