Seeking advice about installing new backing plates on my Ty

[PortTack]

One of my spring projects on our new (to us) Typhoon is to install backing plates on most everything - cabin top cleats, chainplates, mooring cleat, and mast step. I'm skipping the backstay for now since getting to it is such a pain, and nothing looks to rusted when I spy through the inspection port...

I've purchased, measured, and cut backing plates from a sheet of 1/4" G10 for everything, and bent-nail-drilled-out and epoxied all the holes in which the hardware will go through. Now I'm just thinking through the best method for installing the backing plates and re-attaching all the hardware, and here's my question...

My original plan was to pre-measure and drill the necessary holes in all the backing plates, drill through the newly-epoxied holes, back-butter the G10 and install, but I realize now that if I do that, there's zero room for error when drilling through the newly epoxied holes to line up perfectly with the pre-drilled backing plates. If I'm off a couple degrees, my bolts won't line up. I was planning to back-butter all of the G10 plates when putting them on, does it make more sense to back-butter and attach the backing plates *undrilled*, wait for the epoxy to set, and then drill through from above deck? In that scenario, even if I'm off a bit, I'll have a hole that syncs up with the new backing plate.

Pros and cons of either method? Would one method be more structurally sound than another? Is there something I'm not thinking through? Or overthinking?

Appreciate your advice!

[Caral]

Others will likely chime in, but IMHO the loads you’re dealing with are no greater than what fender washers as backing can handle. On my previous TY I replaced the mooring cleat, repaired the deck core at this location, and used fender washers to back it. It had small washers previously. My mooring is quite exposed, but I never had any doubts, as these forces are shear forces. Anyone else?

[radsailor]

I have recently re bedded some deck hardware and used the largest fender washer I could find. If the washer hole was too large for the nut, I added a small washer behind the larger to keep it in place.

[Typhoon4Fun]

FWIW when I got my previous boat, a Typhoon, a bunch of the hardware was installed with washers only, no backing plates. They were smaller than fender washers. But I didn't like it so I filled the holes and bonded in some scraps of fiberglass as backing plates, similar to your plan with the G10.

I set the cleat or whatever on the deck and drilled out two holes kitty corner to each other (use a punch to make a little divot in the epoxy so the drill bit is less likely to wander). Then I set the cleat on the backing plate an drilled out two holes in the same position. I slightly over-drilled the backing plate to make it easier to hit the holes. Once the backing plates were buttered up with thickened epoxy, I used some scrap bolts to hold the backing plates in place and snug them up close to the deck so that epoxy oozed out. Make sure you wax the bolts and nuts so they epoxy doesn't stick. And mask off the deck. I found that two holes (in the case of a cleat with 4 bolts total) were enough to snug the plates in place. Then I went back and drilled all four holes, which meant that two of the holes were drilled in the deck and backing plate at the same time; i.e. no chance of them being mis-aligned. Hope that makes sense and helps..