Excellent, glad to here it!
The existing hole size is fine Dave, however, what you want to do is enlarge the hole through the outer skin of fiberglass only, to 5/16" on your transom to accommodate the larger hardware. That way there is no chipping to the gelcoat/fiberglass while turning in the lags. Here are the installation instructions sent with all Victory trim tabs:
Installation of your Victory Trim Tabs
All Victory trim tabs have been designed to utilize your existing trim tab mounting holes. Owners who currently have a single row of holes will reuse those existing holes and will have to drill their transom for the additional upper row of holes featured on all Victory trim tabs. Those with Bennett ST or HD series, Trim Master, Lenco or Insta-trim tabs will not be required to drill any new holes since these designs already employ two rows of holes in most cases.
1) Remove your existing trim tab plates. If you experience difficulty due to the type of adhesive/sealant used in your original installation it may be necessary to employ one of two methods to remove the tabs:
A) Use a fine piano wire to get in behind your backing plate and in a back and forth ‘sawing’ motion work the wire from one side to the other until the backing plate is free of the transom.
B) Apply a little heat (using a propane torch or heat gun) to the surface of the backing plate only. The heat will loosen the grip of the adhesive/ sealant and make removal of the plate possible. If you don’t feel comfortable employing this method please consult with your local marina/ rigger or feel free to call us for further advice.
2) (For those who currently have two rows of mounting holes, go to step 4)
Temporarily install your Victory trim tabs using the two outermost mounting holes. Carefully mark the upper row of holes on your transom using a fine tip marker.
3) Remove the tabs and accurately drill the mounting holes with a 7/32” drill bit to a depth of 1 ¼”.
4) Next, use a 5/16” drill bit to drill through the outer fiberglass ‘skin’ ONLY, to prevent chipping when turning in the larger mounting screws. (Do NOT enlarge the holes beyond the gelcoat/fiberglass skin) Usually, the gelcoat/fiberglass on your transom will be anywhere from 3/16”-5/16” thick.
5) Use a good quality marine adhesive/ sealant (we like 3M 4200 or 5200 sealants) to coat the threads of the supplied mounting screws and run a small bead around each of the transom mounting holes before installing your new Victory trim tabs.
6) Use a length of masking tape across the hinge to help protect the paint finish while tightening the bottom row of screws. Wipe off any excess sealant from your installation and stand back and admire your work. Job done, time to play!
PLEASE EXERCISE CAUTION WHILE BECOMING FAMILIAR WITH THE WAY YOUR HULL RESPONDS TO YOUR NEW VICTORY TRIM TABS.