Complete stem and its ribs rebuild

[Tom Widney]

I am restoring a 16 foot 1961 OT Guide. When I purchased it in the mid 80’s out of a garage in Albuquerque NM, I was told it was a Peterborough which had been backed into the stern by a car. The car broke two of the lower planks about three inches from the starboard stem, as well tilting the first cant rib at angle, not breaking it, but having pulled out on of the nails at the rail so that same nail would not let the cant rib return to its original location, leaving a severely crooked stem after sitting that way for more than a few years. Also two under stem consecutive ribs were cracked as well.
I bought two replacement stems from Jerry Stelmoks shop last fall, with new serial numbers stamped on it. The original stem was one rib station longer, no big deal!
The big deal comes when closely examining the stem to rib joint on the original keel. The stem no longer lays inline along the axis of the boat but was twisted from get to go all along the length of the stem, leaving what would have been the break point for bending the rib off to one side. Imagine the effect of tilting the stem on the form so that no longer lays flat along the keel line resulting in one corner of the stem being high. Then bending the ribs on would result in a crease in the ribs offset from the centerline.
You can’t just lay the new stem in the rib cradle and nail it in. So what to do now?
I need to replace all of the ribs which lay under the stem.
The first rib counting from amidships is only slightly tilted, less than 1/16 in. This tilt gets progressively more pronounced as it approaches the cant ribs, ¼ in. It would be possible to alter the stem mortise bed so that it would accommodate the tilt and still remain level. I could then clamp the stem at this first rib which would be in the correct alignment. Next the bend points of the rest of the ribs lying under the stem would be cut to allow the stem to lay flat upon the keel line…. then turn my attention to the inwales, deck, and stem junction.
Fit the inwales and the stem to the deck so that the stem would be fastened at both of the extreme ends while laying between the bisected ribs much like cant ribs. These bisected ribs are still held in position by all most all of the planking with exception of the garboard and shear planks.
Then begin bending new ribs, one at a time, starting with the second rib from amidships and working towards the cant ribs while keeping the repair in correct alignment.
Am I on the right track? I have already tried cheating and altering one of the two stems I had ordered to accommodate the twist and still get correct alignment, it was less than successful. Any thoughts recommendations will be much appreciated.
Perplexed Tom

 

[Tom Widney]

More pics
Thanks for your time.
Tom

 

[Larry Meyer]

My quick take is that you may need to bevel the sides of the notches on the new stems, so the profile of the ribs that set in the notches matches better the profile of the notch. The notches are squared and true. The ribs cross over into these notches quite sharply angled.

 

[Rollin Thurlow]

Yes, You need to bevel or taper the sides of the rib notches so they match the angle of the ribs that are going through the notches. A good wood rasp should do the trick. For that first full rib with the off center bend you can 1) bevel the notch of the stem at the odd angles of the rib or 2) cut the center out of the rib and make it into another cant rib and glue a bit of wood into the gap that would be left at the notch. You will not lose any strength or hurt the boat in anyway by making this into a additional cant rib. 3) Replace the rib with a good one before the stem is installed.

 

[MGC]

Yes, You need to bevel or taper the sides of the rib notches so they match the angle of the ribs that are going through the notches. A good wood rasp should do the trick. For that first full rib with the off center bend you can 1) bevel the notch of the stem at the odd angles of the rib or 2) cut the center out of the rib and make it into another cant rib and glue a bit of wood into the gap that would be left at the notch. You will not lose any strength or hurt the boat in anyway by making this into a additional cant rib. 3) Replace the rib with a good one before the stem is installed.

A photo from Rollin's shop illustrating his comment quite specifically.

 

[Larry Meyer]

Universal Canoe Level

I don't know that you need bend any new ribs. Those ribs I see whose cures are less than elegant and symmetrical are about par for the course, according to what I've seen.

With respect to your worry that fitting the stem into those ribs will force the stems out of plumb (which seems to be illustrated in your photos), the notching or Rollin's suggestion should sort that out. I had the same anxiety when I did stem replacement long ago, but things basically sorted themselves out.

On this whole topic though, one thing I am waiting for Rollin to invent is the universal canoe level. We have carpenters levels to sort out when buildings are going up level and true and straight, right? So what we need next is a Universal Canoe Level, which I envision as some kind of little widget, that uses GPS, that you can slap down on any part of canoe and right away it will tell you whether that part of the canoe is in the right spot or of out of plumb or asymetrical from its counterpart on the corresponding other part of the canoe. Take all the guesswork out of this business of getting a restoration right back to where it was when it came of the factory.

 

[Rollin Thurlow]

Well I was working on level system for while but it got quite complicated and frustrating. this is the results!

 

[Larry Meyer]

Good start! I forgot to mention the importance of keeping things flush too.

 

[Tom Widney]

Thanks guys, I'll let you know how it turns out.
Tom