Redoing a 79 mako, epoxy or ester

[fallguy]

You don't need any fibers. The only time I use them is when I am worried about print thru, cte changes or the edge getting hit with a stone and chipping...

just get the transom wood in before you glass wrap

 

[Hojo]

Will do. Thanks..

 

[Hojo]

I'm guessing I need about 30 layers here?...lol...deffinatly gonna have to add a few layers in the bottom area to build up thickness. A days, maybe 2 worth of grinding and cleaning then start adding layers to bring it even to thickness of transom skin above old deck level. I plan on attaching the glass to hull and up to that area. Will start with strips that come up to that and go across the hull starting at 5". Then each one 2" wider. Would you remove fish boxes and expose that part of inside skin too to bulk up a few layers there or leave them? Then after new ply added to outside grind gelcoat and utilize them to attach glass for added strength. Thanks for any advice and ideas...

 

[fallguy]

No.

do that all with the inside skin and tabbing

Grind away all the gelcoat for 8-12" in, and yes on the fishboxes if they are staying, and under them.

Then bond in the plywood layers. Then glass the inside with 12", 10",8" overlaps into the hull and fishbox and under. Some risk here as I assume the fishboxes have strength. If they are really wimpy; they gotta get removed or cut back and repaired
For the main repair.

I really like to go over the top with glass. Exposed plywood will blow open on you. The way I'd do it is to go over the top 12,10,8,6,4" or 2" minimum at the end...with each inside layer, same like the inside.

Then, you'll have a hump on the outside to fair in. Touche'.

There is really no reason to glass that now. Once the ply is there, remove all the gelcoat off the transom exterior, repair your clamping bolt holes for the transom work, consider glassing over it for leak protection, one layer of 1708 and epoxy. Then if you want to gc, you can put something else there.

 

[Hojo]

Ok. The fish boxes are solid. I also plan on fully glassing in the wood. After bonding it in and reinforcing the inside skin as you said the plan is to go from inside over top and down some. Then thought I would come from outside over the top and down inside and vice versa with 4 layers of glass and epoxy resin. Also at the very end of this rebuild I am going to add foam back in both sides from the stringers( 1 from middle 1) to gunnels. Plus replace whatever I remove from there forward. If in fact this does fail, it won't sink...I am no engineer but if I do all this with transom it should hold. I know I have alot of fairing and sanding ahead of me.
I know alot of people wouldn't do this project. Most call me friend. I'm retired and under no time frame. I look forward to the day I step back and "yes" I built this!... just hope it doesn't turn out like the Douglas farm on green acres.. Thanks for advice and more in the future.

 

[Hojo]

Also replacing stringers as these are shot and raising them up about 4". Should I remove about 12-18" of them from transom before starting to lay in so that the glass will be solid bond across the back from hull up? That seems in my mind a good thing?...

 

[fallguy]

Yes. Take them back, make the transom strong and then restore the means to transfer transom loads to the hull with stringer rebuild. Make sure the boat is not sitting and well supported because if you cut the stringers out and the hull sags; you will be creating hook in the hull which makes a planing hull fail epically.

For the same reasoning, I'd cut back the fish boxes. Sorry, but that is what I'd do. Up to u, but if the existing transom is rotten behind the fish boxes, all that work and it'll all be rotten in 5-10 years. Rot is like cancer. Get it all or it'll come back with a fury.

 

[Hojo]

So I probably should have thought this out ahead and asked this question before this point. I have removed the back 12" of the stringers. Boat hull is completely supported and sides also..not moving even when I jumped a little...not hard but just enough to feel comfortable it is not moving. Question now is laying in glass and stringer channels. I assume it is best not to go over them but up to them. Of course I will grind everything as flat as possible across the hull back 12" or so as determined earlier before starting to glass in. What are your opinions on the stringer channels?....Thanks.

 

[Hojo]

Also just saw your last post about behind fish boxes...it appears there was no wood there....I took a long screwdriver and thumped it around in behind and it is hitting the gunnels on sides and I can't see any wood...

 

[Hojo]

This shows a little better....other side...I'm not opposed to removing them if that is better but I thought as they are solid I would utilize them as another point to glass to.

 

[Hojo]

This picture...not sure why same one sent

 

[fallguy]

Grind and fill the stringer channels and make them disappear so your transom glass and tabbing is simplified... going around them is very poor workmanship, imo

 

[fallguy]

So, perhaps the fish boxes were intergral all along.

Still, you need to tab the transom to the sides real well and you can only do so on the inside.

For a moment, consider gluing a niece transom say 2.25", and then not tabbing it to the sides. The forces on the unbonded sides would be tremendous.

glass overlaps on the sides needs to be 12,10,8,6 and in that order....whether the fish box can take the entire load of the engine is the question and one I cannot answer..

how did they keep the transom from stress cracking at the fish box before? Or was it?

 

[fallguy]

Why don't you get some coosa bluewater for that spot? Ain't that big.

 

[Hojo]

No cracks that I can see. I am no engineer but I would say that the "load" was distributed from transom to the sides, stringers and into the deck. It seems to me all worked together for the needed strength. That is a guess but seems to be logical solution. 3 reasons for not using coosa..I live in western ny. So shipping is a consideration, current price is outside my budget and I already have the hydrotek..hope to get grinding/ sanding done in the next day or 2....thanks for advice, helps alot!.. I'm sure I'll be seeking more...