The Grady White I am working on has about 40 cracked ribs from the dashboard back. The ribs are solid except in the relatively short distance where they are tightly bent. I was wondering if there is a disadvantage to scarfing in repairs in all of these ribs versus replacing them all. It seems to me that scarfing will save quite a bit of time, and by cutting the shapes from solid oak, the bent region may actually be stronger than a steam bent (and therefore pre-stressed) rib. Any comments?
Rich
Rib Repairs
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Phill Blank
- Posts: 412
- Joined: Thu Jan 05, 2006 4:20 pm
- Location: Hurley, Wisconsin
Rich,
The problem I see with a cut rib verses a steam bent rib is the grain of the wood. On a cut rib the grain is going to run out at a point where the most stress is which is in the curve. Also the ribs need to flex with the pounding of the water against the hull at speed. A cut rib will not flex and remain one piece.
If you do scarf in new steam bent wood be sure your scarf joints are spread apart and not on the same plank on against ribs.
I could see you using thinner strips of quarter swan white oak and gluing them together to form the ribs rather then a single thicker piece. This would require protecting the rest of the hull around the rib so the adhesive would not run all over the place and make a mess. Or you would need to make forms and bend and glue the ribs on the forms outside of the boat.
In my opinion the way best would be to replace the rib completely with new steam bend ribs which is more time consuming and more work. But, sometimes the longer way of doing things is the better way.
It does not pay to use a short cut that will only patch the problem and then later on you have to do it all over again.
Those are my thoughts.
Good Luck,
Phill
The problem I see with a cut rib verses a steam bent rib is the grain of the wood. On a cut rib the grain is going to run out at a point where the most stress is which is in the curve. Also the ribs need to flex with the pounding of the water against the hull at speed. A cut rib will not flex and remain one piece.
If you do scarf in new steam bent wood be sure your scarf joints are spread apart and not on the same plank on against ribs.
I could see you using thinner strips of quarter swan white oak and gluing them together to form the ribs rather then a single thicker piece. This would require protecting the rest of the hull around the rib so the adhesive would not run all over the place and make a mess. Or you would need to make forms and bend and glue the ribs on the forms outside of the boat.
In my opinion the way best would be to replace the rib completely with new steam bend ribs which is more time consuming and more work. But, sometimes the longer way of doing things is the better way.
It does not pay to use a short cut that will only patch the problem and then later on you have to do it all over again.
Those are my thoughts.
Good Luck,
Phill
I agree with Phil on this one. Do not use cut ribs, they will split right along the grain.
While scarfing is a proven method in woodworking I am not sure that I would want to scarf 40 ribs on the curve.
The time it would take to remove the bad pieces,cut-trim and fit the new pieces and then screw them all together while it all dryed is mind boggling.Plus you are doing all of this with the good parts of the ribs still in the boat.
Not to mention having to make a jig that you have to be able to change for each set of ribs.
Steam bending is not as difficult as some would have you believe. I just replaced another 5 ribs on my Off Shore yesterday with no breakage at all.
4 more to go and the starboard side will be done and I will flip the boat.
Good luck and keep us posted.
Karl
While scarfing is a proven method in woodworking I am not sure that I would want to scarf 40 ribs on the curve.
The time it would take to remove the bad pieces,cut-trim and fit the new pieces and then screw them all together while it all dryed is mind boggling.Plus you are doing all of this with the good parts of the ribs still in the boat.
Not to mention having to make a jig that you have to be able to change for each set of ribs.
Steam bending is not as difficult as some would have you believe. I just replaced another 5 ribs on my Off Shore yesterday with no breakage at all.
4 more to go and the starboard side will be done and I will flip the boat.
Good luck and keep us posted.
Karl
I tightened up all plank fasteners and removed my first (out of a total of 40) cracked rib. The rib had obviously been cracked for a very long time. The rib broke with no effort at all once I removed all of the screws holding it. The boat was holding the shape of the rib more than the rib holding the shape of the boat.
After breaking the rib the rest of the way, I noticed that the cracks had started right where the screw went into the rib at the sharpest bend in the rib. There is no doubt that the screw played a role in the failure. I am thinking of leaving the screw out at this location when I install a new rib. There are plenty of other screws along the length of the rib. Does anyone think leaving one screw out would be a bad idea?
Also, considering the number of cracked ribs and the extent that many of them are cracked, should I be concerned about the overall shape and symmetry of the boat? It looks fine on the trailer, but I am wondering if I need to be measuring some things. There are no problems with ribs from the dash forward.
Thanks as always for your help.
Rich
After breaking the rib the rest of the way, I noticed that the cracks had started right where the screw went into the rib at the sharpest bend in the rib. There is no doubt that the screw played a role in the failure. I am thinking of leaving the screw out at this location when I install a new rib. There are plenty of other screws along the length of the rib. Does anyone think leaving one screw out would be a bad idea?
Also, considering the number of cracked ribs and the extent that many of them are cracked, should I be concerned about the overall shape and symmetry of the boat? It looks fine on the trailer, but I am wondering if I need to be measuring some things. There are no problems with ribs from the dash forward.
Thanks as always for your help.
Rich
If you are steambending the new ribs and put all the screws back in right away they should not crack the ribs. If you only use a few and wait till later to put in the rest of the screws I would advise drilling a pilot hole first. I was just out in my shop doing that very thing. The first three ribs I replaced I only put in every other screw to save time. When I went back three days later to put in the rest I heard a cracking sound as I put in the first screw. Nuff said. On the next set of ribs that I installed I took the time to put in all the screws. No problems.
Many of the factory screws on my boat where way off center of the ribs or poked thru. And at least one of the ribs was cracked from when the floor riser screw was installed. Most likely from the factory.
To help the hull retain it"s shape I only removed every other rib that was broken. Repalced those and then did the same thing again. Even though the ribs are cracked they still help hold it all together. And if you feel the need to, do a diagonal measure of the cockpit area and see what you find. If it is sitting well on the trailer with the bunks set up right you should be good.
Hope this helps.
Karl
Many of the factory screws on my boat where way off center of the ribs or poked thru. And at least one of the ribs was cracked from when the floor riser screw was installed. Most likely from the factory.
To help the hull retain it"s shape I only removed every other rib that was broken. Repalced those and then did the same thing again. Even though the ribs are cracked they still help hold it all together. And if you feel the need to, do a diagonal measure of the cockpit area and see what you find. If it is sitting well on the trailer with the bunks set up right you should be good.
Hope this helps.
Karl
I think you should replace all of the screws. That is what holds the planking in place and keeps the shape of the boat correct. Replace the screws as soon as you can after the steam bending and that should eliminate the cracking of the ribs. But that is just my opinion.
Bill
Bill
All Dunn ll
'59 Sea Lancer
'59 Sea Lancer
I agree with Bill.
I put that screw in right away as it helped to keep the rib tight aganst the curve of the hull while the rib was still pliable.
The thing is this as I see it. Change one thing and you change it all. When restoring things I tend to put it back as original and then if I have too add things I will.(bracing,sisters,ect). Bearing in mind what those add on's will do. I very rarely leave things out that were there to begin with.
Hope this helps.
Karl
I put that screw in right away as it helped to keep the rib tight aganst the curve of the hull while the rib was still pliable.
The thing is this as I see it. Change one thing and you change it all. When restoring things I tend to put it back as original and then if I have too add things I will.(bracing,sisters,ect). Bearing in mind what those add on's will do. I very rarely leave things out that were there to begin with.
Hope this helps.
Karl