1984 Grady White Overnighter 20 - Transom Rebuild

Questions about boat repairs with our resins and fiberglass: hull patches, transoms and stringers, foam, rot etc.
fallguy1000
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by fallguy1000 »

FlounderPounder wrote: Mon Apr 10, 2023 9:18 pm So I got the 3rd and final piece of plywood glued in today for a total of 1.5”. Once that is done setting, I plan to start glassing the transom next week after my son goes back to school after Easter break. I have a few questions for you guys if you don’t mind me asking;

1: I pretty sure I know the answer to this, but just want to make sure; I have to install and glass the stringers into the transom wood BEFORE I glass over the transom, correct?

Either is fine. The transom on an outboard transfers loads into the hull via knees or stringers or both. Load transfer requires continuity; not order of operations.

2: Once all the stringers are in and glassed, next is the transom. I know I need a fillet around the perimeter of the transom, my question is; after the fillet, do I use tape over the fillet first, then the full sheets of glass?? Or lay the full sheets of glass directly over the fillets?

You can also use the glass on the transom to tab the transom to the hull. This is done longest piece first. The glass can also go up and over a rounded transom top, onto the bottom and the hullsides. If you bond in stringers; you won't have enough glass for that and must tab them in. Tabbing only should use large pieces of 1708. The minimum tabbing I would use for any large outboard is something like 10,8,6,4 which ends up only offering 5" on the hullsides. And this is why I prefer to wrap with the glass because easy to wrap 10-12" extra each side. (Laminating tip-roll into inside corners only and roll away from outside corners only). A large 8" tabbing tape only gives a 4" tab to each side...

3: For the glass, I know you guys recommended using 17oz, but I only have enough 17oz for 2 layers. Would I be better off doing 2 layers of 17oz and 1-2 layers of 13oz? Or 2 layers of 17oz and 1 layer of 1708? What weight will be easier to do the splashwell with?? 1708 or 13oz? Because that will probably make my mind up about the transom glass. I should have bought less 1708 and more 17oz…trying to get this all done without placing another order, but I doubt that will happen.

Like I said, the ideal is to make the transom glass lay on the hull sides and bottom 10" extra, then 8" xtra, then 6" xtra, and 4" extra. Base your decision on what pieces are large enough...

I will have to place another order anyway for some fairing putty and some paint and/or gelcoat so I can always just get more of the “correct” weight glass when I place that order.

Thanks again for all the tips guys!! And hope you all had a great Easter!!

Matt
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fallguy1000
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by fallguy1000 »

What glass is 13oz?

You need to only use biax.

Tom's answers are also good ones, I prefer the larger transom glass panels versus tabbing...and I'd do the transom first to allow the large panels to hit the hull bottom..

FlounderPounder
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by FlounderPounder »

Thanks for the tips Tom!! I like the idea of the glass then the stringers to avoid cutting around them!! Unless there is a “structural” reason to do it the other way, then I’ll go with your suggestion.

As for the glass, I use the two 17oz and two 12oz (maybe it’s 13oz, I can’t remember…it’s one or the other). Then I’ll use the 1708 for the splashwell and probably add a few more yards of 17oz and 12oz when I order the quick fair to finish the splashwell with.

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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by FlounderPounder »

Fallguy, I was mistaken…it’s 12oz biax.

So I’ll do two layers of 17oz and two layers of 12oz

And 3 layers of tape in the corners first.

Thanks again for all the tips…

fallguy1000
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by fallguy1000 »

FlounderPounder wrote: Mon Apr 10, 2023 11:30 pm Fallguy, I was mistaken…it’s 12oz biax.

So I’ll do two layers of 17oz and two layers of 12oz

And 3 layers of tape in the corners first.

Thanks again for all the tips…
Taping the corners first would not be best practice.

The reason for this is you create uneven surfaces woth each tape and then the only way to avoid entraining air and doing subpar work is to grind it and then prefill the tapes with thickened resins after precoating the transom. A semi-pro understands this headache, and would tab last.
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fallguy1000
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by fallguy1000 »

Strength in fiberglass does not come from a shingle effect, but thickness and work quality.

When you lay tabbing tapes, the largest are first. This argument tends to go in circles sometimes. The only time smallest is first is when you are filling a void or low area and a concave hole or similar.
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FlounderPounder
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by FlounderPounder »

fallguy1000 wrote: Tue Apr 11, 2023 8:16 am
FlounderPounder wrote: Mon Apr 10, 2023 11:30 pm Fallguy, I was mistaken…it’s 12oz biax.

So I’ll do two layers of 17oz and two layers of 12oz

And 3 layers of tape in the corners first.

Thanks again for all the tips…
Taping the corners first would not be best practice.

The reason for this is you create uneven surfaces woth each tape and then the only way to avoid entraining air and doing subpar work is to grind it and then prefill the tapes with thickened resins after precoating the transom. A semi-pro understands this headache, and would tab last.
Ok, that makes sense. Thanks!! So, I’ll fillet the corners, then lay the largest full sheet of glass down first. Then go smaller and smaller from there. Correct?

fallguy1000
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by fallguy1000 »

FlounderPounder wrote: Tue Apr 11, 2023 9:29 am
fallguy1000 wrote: Tue Apr 11, 2023 8:16 am
FlounderPounder wrote: Mon Apr 10, 2023 11:30 pm Fallguy, I was mistaken…it’s 12oz biax.

So I’ll do two layers of 17oz and two layers of 12oz

And 3 layers of tape in the corners first.

Thanks again for all the tips…
Taping the corners first would not be best practice.

The reason for this is you create uneven surfaces woth each tape and then the only way to avoid entraining air and doing subpar work is to grind it and then prefill the tapes with thickened resins after precoating the transom. A semi-pro understands this headache, and would tab last.
Ok, that makes sense. Thanks!! So, I’ll fillet the corners, then lay the largest full sheet of glass down first. Then go smaller and smaller from there. Correct?
Yup
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viewtopic.php?f=12&t=62495

FlounderPounder
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by FlounderPounder »

I grinded the “back side” of the transom glass at the top and corners today to get it ready for glassing. I’ll post a few pics, and ask for some input on whether or not I ground it down far enough from the edge. I’m 99% sure I ground it deep enough…progressively shallower as it got further from the edge. It’s basically ground to “nothing” right at the edge.

Currently, it’s ground down about 4-5” from the edge of the transom. I believe that should be far enough, but I defer to the experts here.

On a side note; I am NOT the one who scratched the shit out of the gel coat down where the bottom paint goes. I used bottom paint stripper the other day to remove all the bottom paint from the back to find that whoever owned the boat before me must have used a grinder to get bottom paint off at one point and put swirl scratches all throughout the gel coat. So please don’t think I’m the idiot who did that…lol.
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fallguy1000
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Re: 1984 Grady White Overnighter 20 - Transom Rebuild

Post by fallguy1000 »

Nice work.

Precoat all raw wood before glassing. End grains really suck resin; I would precoat and then again in 30 minutes; pure epoxy, no thickeners.

The best way to laminate is longest pieces to the edge of the taper first.

Looks good.
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