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Reply to: NACRA 5.8 - large hole repair (looking for techniques/advice)

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[quote=Edchris177][quote]I am also thinking about filling the tubes that are intersected by the damage with closed cell expanding foam.[/quote]
Don't do that. Even the low expansion foam "expands". I have seen some types push a door & window frame enough to jam the door. You might blow the tube off the hull. It will absorb water over time, also not good.
From where the hole is, I think I would add some layers to the keel, the cracks might very well go further than it looks. You need to grind out the cracks to solid material. Your first post photo sure seems like it goes to the keel. Probe/grind all those cracks to their ends.
Now that I see the damage is below the front decks, I would also do as Arch says & remove the cover. It's not too big a job, & will greatly simplify the work, especially adding the stiffening tubes. You don't need to line the tubes up exactly with the old ones, they could go just above, below the old ones, & overlap the ends of the old.
I think those hulls are symmetrical. You can make a perfectly molded patch by placing Saran Wrap on the inside of the opposite wall. Then lay 1 or 2 layers on top og the Saran Wrap. When it sets up, you will have the exact contour of the inside of the hull. (You will have to add some material to the "1/2 tubes" for stiffening.
There is a very inexpensive power tool that will buzz those decks off. It looks sort of like a set of barber buzz clippers. A buddy who is resurrecting a Nacra 36 showed it to me. It vibrates horizontally while it cuts/separates. Makes a very clean job.
Plan & organize, you can fix that hull to good as new strength, the cosmetics won't be as good as new though. 
Rough up the inside & wipe down with acetone before you lay the first layer up, be careful not to contaminate with grease etc. Buy a box of latex gloves for $10, you'll use quite a few.
Here is lots of good info on additives & HOW TO. [url]http://www.westsystem.com/ss/the-105-system/[/url]
I can't find my link for materials like cloth tape & roving, I think it was Johnson Distributers??? Maybe somebody can chime in on that. 
Take lots of photos,  (helps to have a GF take photos, you don't want to handle your camera while handling resin) make an album, we want to see the result, & it will be of great help to the next guy who does something similar.[/quote]

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