Wood screws or bolts for transom board

[trailblazer2]

I am replacing the 1" x 8" transom board on my 15' Lowe aluminum boat that has an 18 HP motor. I have drilled out all the rivets (total of 18) and removed the old board and brackets & braces holding the board in place. I will seal/coat the new board with Gluvit and plan to use 1/4" stainless bolts and (possibly) SS wood screws to reinstall the the new board and brackets. As can be seen in the attached pic, there are only 6 of the previously removed LONG rivets that must be replaced with 2" through bolts & self-locking nuts.. the 2 at the top of the transom and the 4 attaching the top of the knee brace to the transom board. I have 3 queqtions:

1. Is it necessary to have the board secured to the aluminum transom skin on the boat? [I assume the answer is YES, since that was the way it
was originally installed.
2. What are the pros and cons of using 1/4" x 1" SS wood SCREWS in places where through bolts are not required?
3. Is there a need and/or BENEFIT to gluing the board to the transom skin in addition to bolting and screwing to secure?

The reason I am considering screws, is because of concern that I cannot drill holes through the new board and hit the old holes in the brackets on the opposite side. Actually, I am also thinking of replacing the "Z-angle" bracket with a rigid 1" x 1-1/2" aluminum angle... don't see any reason to re-attach the "Z" to the transom skin.... it is "flimsey" and provides no APPARENT structural support.... will catch and hold water to possibly rot the bottom edge of the new board.

There are numerous "extra" holes and corrosion spots in the transom skin which I plan to fill with Marine-Tex Epoxy Putty.

 

[jigngrub]

Re: Wood screws or bolts for transom board

Fasten the board to the skin like it was originally installed.

It will be a much more sound installation if you use thru bolts.

As far as not being able to hit the holes on the other side, drill half way through on one side and then drill through the other side. Your drill bit will find the half way through hole and be guided through to the other side.

I'd reinstall the "Z" but maybe drill 3 or 4 holes in the bottom for drainage. It provides more structural support than you may think.

If you're using Gluvit for a sealer you need to paint over it to protect it from UV rays. I'd suggest a good porch/deck paint instead.

 

[trailblazer2]

Re: Wood screws or bolts for transom board

Thanks for your input! Will use ss thru bolts. Have filled all unnecessary drilled & corrosion holes with epoxy putty and now ready to attach epoxy coated and painted transom board.

Had a "brain storm" on how to seal the new bolt holes and prevent future corrosion due to dissimilar metals.... I am thinking of filling the newly drilled (drilled oversized??) holes in the wood transom with epoxy putty ( JB-Weld or equivalent) before inserting the bolts and making sure there is a layer between the washer and the outside of the aluminum skin. Will this procedure accomplish my objectives?? What "negatiives" am I overlooking?