when to replace rib.....

JPembleton

Chest Nut
What is considered a rib that needs replacing? Currently I'm working on a 15' Chestnut chum, I need to replace at least 8 or 9 ribs for sure but there are a few more that have the common hairline cracks in them that I am unsure of.

The ones with the hairline cracks seam structually sound as the cracks do not go all the way thru the rib..... but should I fix em now while I have the chance or not worry about it.

My work does not meet the quality of most here so I'm not after the "perfect" restoration. I'm thinking I can just leave the little hairline cracks in place but if there is a reason not to someone let me know.

Jamie
 
Hairline cracks are common. You might consider only replacing the ribs that are obviously in need and try to repair the other hairline cracks by opening the gap as much as possible and injecting a bit of epoxy in there. While you have the seriously broken ones out, you may be able to better judge the cracked ones by pushing on the outer hull and seeing how much they move. Also, don't try to replace all broken ones at the same time as the hull my become mishaped. Remove and steam bend in several at a time.
 
When I was restoring my 18 OGL I noticed two ribs with very small lateral cracks...not wanting to take a chance, I took them out and found that they were still good and strong when flexed...But I did do what is suggested above. I flexed them a little to widen them just enough to get some eposy in there and then put back pressure with two small pieces of wood held with a brace until the epoxy squeezed out of them....when the were good and dry, you could not tell them from a new one as far as strength goes...so I replaced them and called it a good job...they were out and back in the same day...
 
Backside Rib Repair

Jamie:

Search on "backside rib repair". If the crack is not on the turn of the bilge or something, remove the planking and carve out a notch in the backside of the cracked rib across the crack. Epoxy in a new piece of cedar or some folks use hardwood, sand flush and re-install plank.

Fitz.
 
good way that Fitz did it...wish I had read that before I did mine...alot easier to replace a small section of plank than pull all those clinche nails...Especially if those "iffy" ones are where your taking out those broken ones...
 
Fitz said:
Jamie:

Search on "backside rib repair". If the crack is not on the turn of the bilge or something, remove the planking and carve out a notch in the backside of the cracked rib across the crack. Epoxy in a new piece of cedar or some folks use hardwood, sand flush and re-install plank.

Fitz.

The cracks are on the topside. I'm guessing this method would be for cracks on the bottom side of the rib. Otherwise, I'd be carving away the only good wood holding the rib together.

I think there may be a rib or two that are cracked from the bottom that I had planned to just replace all together. This method might be more suitable.

Thanks

Jamie
 
Notch

I'm not sure I have a photo, but I carve a substantial "notch" in the back of the rib. I probably only leave 1/8th of an inch (maybe even less) of the thickness of the rib on top, so the bulk of the wood in the vicinity of the crack and 2 inches or so on either side gets replaced with a new piece of cedar epoxied in. Sometimes the epoxy will work itself into the crack from the back when the new piece is clamped in to dry.

You can do it in a few minutes with a sharp chisel and you have a substantial rib repair when done. Just seems easier then trying to work epoxy into a hairline crack.

PS. Another point worth mentioning is even if you repair the crack, when you are done with your restoration you will still have to look at the crack through your new gleaming varnish. If that bothers you, consider replacing the rib. I will do the backside repair for small cracks in canoes that will be my tripping canoes etc. that will see a good hard life. If you are rehabbing a fancy canoe or doing a canoe for someone else it may make sense to replace the rib altogether.

Cheers,

Fitz.
 
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Another point worth mentioning is even if you repair the crack, when you are done with your restoration you will still have to look at the crack through your new gleaming varnish. If that bothers you, consider replacing the rib.

But a replaced rib will visibly stand out far more than a harline crack in a rib. New cedar is very difficult to match to old. Some people stain entire interiors in attempts to get a match, but stains muddy up the appearance of the wood. Staining the new rib only can work, but again, it's nearly impossible to match new wood to old. Even if it looks good when you do it, in different light or from a different angle or after applying varnish that stained rib will stand out from all the others. A hairline crack looks like an earned piece of history.

About that crack only being in the interior surface of the rib... If it were only in the top 1/16" of wood, it wouldn't really matter, but surely it goes much deeper. With support from the surrounding ribs and planking, a single harline crack may not present much of a problem, but it might be a good idea to repair it. The old back-side rib repair as Fitz outlined works very well.

Michael
 
Fitz said:
PS. Another point worth mentioning is even if you repair the crack, when you are done with your restoration you will still have to look at the crack through your new gleaming varnish. If that bothers you, consider replacing the rib. If you are rehabbing a fancy canoe or doing a canoe for someone else it may make sense to replace the rib altogether.

Cheers,

Fitz.

I don't have the tools or experience to worry about appearance. If it floats when I'm done then I have accomplished my personal goal.

If it paddles somewhat straight even better :)


I'll look at the ribs in question and base my repair (or not) on how hard it is to remove the them.
 
Hi Jamie,

You raise a good point... seems we ran right past the issues of ease of repair and tools/expertise required. In fact, a back-side repair may be substantially easire than replacing a rib, and it may do less damage to your canoe.

Replacing a rib requires removing all of the tacks around the entire circumference of the hull, removing the nails holding the rib to the inwale, cutting rib stock, shaping and stem-bending a new rib, and installation with new tacks all the way around. Hopefully the rib stock and steaming work well and the rib doesn't crack, and hopefully the tacks don't split it. I'm not arguing against rib replacement- it is often the best choice. However, back-side repair may be much easier if it is warranted (i.e., the rib is essentially intact, the hull is not mis-shapen at the break point, etc.)

Back-side rib repair requires removal of only the tacks within maybe 6-8" around the rib crack, cutting out that section of planking (you'll save this and replace it later), cutting a back-side channel as Fitz describes, shaping and gluing in a small piece of wood, and shaping that piece with a plane, spokeshave, rasp, file or something similar. Then replace the planking that you removed using new tacks. Assuming that the break is not severe, this repair is far less time consuming, and it is less likely to cause a mis-shapen hull.

Don't worry too much- whichever method you choose, you'll make the canoe float and you'll be pretty proud of your work.

Michael
 
When I am taking ribs out, I do not pull the tacks out from the outside as this just tears the planking. I use an angle grinder with a course sanding disk on it and grind down the clinched nails from the inside. Goes very fast. The rib just falls out and planking for the most part is in tact.
 
Here is a picture of a backside repair. I used a 1.5" X 3" piece of fiberglass cloth and epoxy, but I believe now (that I have found the one true religion) a piece of wood would have been better. I carved out a 1/8" deep rectangle behind the crack and fileld it with cloth and thickened epoxy.
 

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ribs replaced... canvasing can wait

All the work is done on my Chum except the odd tack and the canvas job. After replacing as many ribs as I did I though I might have been better to just pull them all out :).





Did not plan on staining the ribs but I figured since this was just another canoe to "learn from my mistakes" on, I gave it a shot.



A couple of coats of varnish later and the new ribs blend in pretty good.
I'll be waiting for warmer weather before I canvas the canoe.

Jamie
 
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