Rib replacement

[1stwoodenboat]

i'm about to try to replace alot of cracked ribs in my 25ft halvorsen cruiser & hoping to get some advice.the boat is carvel planked in oregon(fir) with spotted gum ribs,most of which are cracked at the turn of the bilge,right behind the stringer.i was planning to remove the deck & replace the ribs rather than fit sisters,my main concern is how to refasten the ribs to the 3 stringers each side,the ribs are currently screwed to the stringers from the outside in,to do this again means i'll have to remove a few planks.would it be sufficient to screw stringers to the new ribs from the inside out?any advive would be greatly appreciated.

[Peerie Maa]

Should be OK. How are you getting the old screws out? Cutting them flush to the stringer?

[wizbang 13]

stringers are a real PITA . This an amateur built vessel? Got pics?
Spotted gum, I'm not up to speed on that. Only wood I ever heard called gum, would've had to saw the frames. Are yours steamed?
6 stringers in a 25'er? What if they had just built the GD frames bigger in the first place!

[Todd D]

I just did that on my 32' power boat. I screwed the new stringers to the ribs from the inside. I used two bronze screws per rib.

[1stwoodenboat]

thaks for the fast response guys,yes the frames are steamed,the bronze screws fastening the planking are very brittle,so was going to cut the existing ribs at every plank & split them,hopefully will be able to push old screws out from the inside without damaging the planking,boat is professionally built,existing screws for ribs to stringers are galv & in very poor condition,should be able to cut flush as mentioned,will try for pictues in the next week or so

[Peerie Maa]

That does not sound good.
You will find it quite hard to push the screws out without the heads breaking out some of the wood around the counter bores. You really should try to remove them from outside, or have a workmate hold a dolly on the outside as you punch them through.
I would try to remove all of the iron screws, If they are in poor condition, the stringer is probably a bit nail sick as well, so you may be able to push them out between the stringer and plank either ford or aft.

[wizbang 13]

...not sounding good at all....mixed metal, brittle bronze.
this may be a job for.. .... "Think out of the box Man"

[1stwoodenboat]

the gal screws into the stringers were a bit of a suprise,but the have lasted over 50 years so maybe the fact that they aren't in contact with seawater has helped them.the screws fastening the planking are only slighlty countersunk with a small amount of putty over the heads,haven't been able to remove any without half of the head snapping off,but after removing the rib & pushing & turning the screw fron the inside they seem to come out with very little damage to the planking,although it is going to be very time consuming

[Lew Barrett]

I am surprised to hear that a Halvorsen would have any iron fasteners at all. For those unfamiliar, Halvorsen was a very respected Australian family owned yard that did very respectable work and whose boats are highly valued today in Oz. Worthwhile project for the right person if she offers good prospects.