Scarfing Ribs

Pat · Post by **Pat** » Sun Jun 03, 2007 1:58 pm

I just acquired a 1961 15' 4" Thompson and it definitely is a restoration project. Most of the bottom planking is rotted along with many ribs. Someone fiberglassed the interior of the bottom and water got trapped. It looks like about 16 to 18 ribs (port and starboard) need to be replaced. Can ribs be successfully scarfed? What is the procedure for doing this and are there any limitations as to where the scarf cannot be? Is it easier just to replace the rib in certain situations? Hope you someone can give me some scarfing techniques and tips. Last question. Is the the scarf glued with epoxy or resorcinol?

Pat

a j r · Post by **a j r** » Mon Jun 04, 2007 3:50 am

Welcome.

Yes, ribs can be scarfed. You do not want all the scarf to line up and be in the same general area. Do not use epoxy with white oak - it just doesn't work very well. Resorcinol or other waterproof adhesive is better.

Do not remove all the bad ribs and then start replacing them. Do every other one, leaving some in place as you work. Make sure you maintain the correct hull shape.

Andreas

Pat · Post by **Pat** » Mon Jun 04, 2007 2:20 pm

Thanks Andreas for your reply. I'm still a little confused. How is a rib scarf done on an existing rib inside of the boat right against the planking (what is the procedure)? Second, I've read other posts where a full bottom reconstruction is performed with the boat upside down starting with the keelson, sister keelsons, ribs, bottom planking and finally the keel. If this is correct, I am having trouble understanding how to bend ribs without any hull shape to guide the curvature of the rib i.e no planking? It seems alot easier to replace a few ribs when the boat is right-side-up and follow the curvature of the hull planking as you bend. Am I missing something or is rib replacement on an upside down hull without any planking installed (total rebuild) a different process? Does anyone have any pics of this type of restoration?

Pat

a j r · Post by **a j r** » Tue Jun 05, 2007 5:04 am

You're correct, you cannot install new ribs if the planking is gone.

I have cut out portions of bad ribs (bad, bad rib, go to your room and you're not getting any supper!). You use a small hand saw and cut at an angle. You have to sand off the paint on the bottom of the hull to find the puttied over fasteners. Remove the putty to reveal the screw and back the screw out. You will have to cut the screws and nails off under the keelson and sister keelsons (stringers). Slip a hack saw blad between the top of the rib and bottom of the keelson or sister keelson.

Make a new rib from all heartwood white oak teh same dimensions as the old rib. Cut a scarf of its end and dry fit it to the existing. Glue it and I typically will also put a screw thru the scarf joint.

Andreas

Pat · Post by **Pat** » Tue Jun 05, 2007 2:20 pm

Thanks, that all makes sense now. One more question. I assume I can replace the bottom planking without replacing new ribs until all the new planking (hull shape) is there for steam bending in the ribs. Are the new ribs added once the new keelson and sister keelsons are installed or is there a different procedure? Remember I am looking at scarfing probably 10 ribs on each side and replacing another 8 to 10 ribs along with replacing about 40% of the bottom planking (from sister keelson to sister keelson).

Pat