Laminate sister ribs

[cape cod]

I have a small 17' center console plywood lapstreke boat. There is some rot in approximately 6 ribs where they run under the deck. The ribs are solid from the gunnels down to just below the deck. The ribs are made of white oak and are 1" wide x 3/4" thick. There is 5" between each rib. I'd like to sister in some laminate ribs and would appreciate any books, articles or general advice on this repair.

[Ron Williamson]

I had the same problem with my Peterborough.
I used a small angle grinder with a sanding disc on it,to remove the soft parts and smoothly taper the remaining part.Then I glued some thin(1/8") laminates in place and used the grinder to level and fair the new part into the old.
No sisters required.
R

[htom]

I would think that the easy way to do this would be to steam up an oak replacement for the first rib and clamp it in place next to it. When it's dried, remove the offending rib and replace it with the new one. Doing them one at a time, with the old one still in place, how much can the boat shape change?

Or laminate a replacement in place next to the rotten one and replacing the rotten one when the laminate has dried and had the edges cleaned up. Again, one at a time.

[imported_Jimmy]

Replacing whole or partial ribs is a MUCH better solution than sistering ribs. There are lots of books with sections on this topic. I think Wooden Boat even has one. Sistering is a quick fix or solution where replacing isn't possible or isn't practical. If you can get out the fasterners from the rotten section of ribs without damaging the planks, you can just re-use the holes to fasten the new ribs. Do a lot of reading before sistering ribs. If done incorrectly it can lead to more trouble than it solves. If you do go with sistering, also consider placing the sisters between ribs rather than right up against them, and make sure there is lots of overlap with good sections of old ribs and that the sisters are tapered on the ends to avoid hard spots. If you can get good access to the area, the preferred solution would be to completely replace bad ribs or scarf in new sections. There is also a dished scarf technique for very short sections, but this is uually for broken or cracked ribs. Make sure you get every bit of rotten wood out of your boat and some of the good wood around it to be on the safe side. Good luck.

[cape cod]

Thank you all for the for the thoughtful responses. The rotten part of each rib is approximately 27" long the rot starts at the bottom of the gunnel and extends out to the center of the boat. I have complete access to each rib. The idea of cutting the rib just above the rot and replacing the rotted section with laminate sounds like a good idea. Can I simply butt the new laminate rib section up to the original rib or should they be connected somehow.
Please forgive me if I misuse certain terms I'm unfamilliar with the terminology. What I do know is I love this little wooden boat and I'd like to continue using her for years to come.

[Bruce Hooke]

No, don't butt -- make a scarf joint.

This is likely to be more work than bending in new ribs but bending in new ones requires complete access to the area, which you may not have...

[cape cod]

I have total acess to the ribs that need replacing. I assumed that removing just the rotten part of the rib and laminating a new section it's place or sistering in a new rib would be the easy way to go. My plan was to make up a new rib or section of rib and screw it in next to the rib that has rotted. After making the new rib should I cut the entire old rib out and slide the new rib in its place? Is it correct to say that when you make a new rib you always make it in place on poly so it can be taken out and worked smooth, prior to screwing it in place? How difficult is steam bending and where can I find directions on building a steam box.

[Domesticated_Mr. Know It All]

Found this online and it describes the process pretty well. Still looking for instuctions for building one. Hang in there, sounds like an interesting boat. smile.gif

Before I can add the white-oak ribs to the boat frame, I have to steam them to make them bendable. In the first photo, you see me putting a rib into my steamer, which is a piece of high-temperature PVC tubing connected by a radiator hose to a pressure canner filled with boiling water. I try to maintain a good process by keeping about four ribs in the steamer at a time. The rule of thumb for steam-bending is to leave the rib stock in the steamer one hour for every inch of thickness. Since my ribs are a half-inch thick, I leave them in for 30 to 45 minutes. When I take a rib out of the steamer, it bends like a wet noodle.

Once I remove the rib from the steamer (yeah, it's hot), I have about two minutes to clamp it to the keel and then bend it and fasten it to the frame. If I wait longer than two minutes, the wood cools and won't bend. I start attaching ribs in the middle of the boat and work outward.

[cape cod]

So the rib is permanently fastened in place while it is still hot. Should a pilot hole be drilled through the new rib to insure the proper placement of the screws?

[Domesticated_Mr. Know It All]

This webpage has some good info....

http://www.ceolas.org/instruments/bodhran/santin/MakeBox.htm

A picture is worth a thousand words....

http://www.ceolas.org/instruments/bodhran/santin/PVCBox.gif

You can make em out of wood too......

http://www.ceolas.org/instruments/bodhran/santin/BxPlns.gif

There have been some good posts about steam boxes and bending on this forum but the search function is currently on the fritz. :rolleyes:

Hope this helps. ;)

[ 04-12-2005, 10:03 PM: Message edited by: Mr. Know It All ]

[Domesticated_Mr. Know It All]

Clamp it in place, let it cool, then drill a pilot hole.

[cape cod]

Thank you. I'll be sure to check ou the website you have suggested.

[Domesticated_Mr. Know It All]

Welcome to the forum Mr. Cod. :D
I see you've been lurking for awhile. ;)
What kind of boat is this?
A Lyman perhaps? smile.gif

[Bruce Hooke]

Originally posted by Mr. Know It All:
Once I remove the rib from the steamer (yeah, it's hot), I have about two minutes to clamp it to the keel and then bend it and fasten it to the frame. If I wait longer than two minutes, the wood cools and won't bend. I start attaching ribs in the middle of the boat and work outward.You may have 2 minutes to get it fully clamped in place, but in my experience you'd best get most of the bend into the piece in the first 30 seconds. This is not as hard as it sounds if you have everything set up. The goal is to get it held in place quickly, by whatever means necessary, until it cools for a few hours. Then you can come back and add all the final fasteners.

One other thought: steam bending is fun; messing with epoxy, and especially cleaning up the squeeze out, is NOT fun! :D

[cape cod]

I don't know the make of this boat. I tracked down the guy who first did some work on her and he claims to have traveled up to maine to get her and thought the builder may have been White (Joel White). A boat builder in the area thought she was made some time in the late 1950s. She is made of plywood with an oak transom, oak rubrails and a mahogany foredeck. She is approximately 17' long with an 8' beam center console. I honestly don't know who made her but most agree she's very pretty. if anyone has any thoughts on how I could find out for sure who made her please let me know.

[Domesticated_Mr. Know It All]

You're just going to have to learn how to post photos Mr. Cod. :D

Sounds like a wonderful boat. :cool:

[cape cod]

I'd be happy to post photos at some point. The last couple of years I've just used her for fishing. However, I would like to do some of the structural repairs she needs and shine her up.

[Domesticated_Mr. Know It All]

You might send a photo to these fellows.
They should be able to tell you for sure. ;)

http://www.brooklinboatyard.com/boats.html

[Stan Derelian]

I don't think anyone mentioned it, but if you are going to put in new ribs, use freshly cut white oak. It steams and bends much easier. A good woodyard can steer you right.

I had the choice of messing around "fixing" bad ribs, and the old guy that helped me said that its easier to replace them than screw around scarfing in or sistering the old ones. He was right. Much easier and cleaner. I would recommending trying to find someone in your area with a bit of experience.

[cape cod]

After reading all of the responses. I have decided to try and steam bend in some new ribs. I'll bend the new ribs in beside the ribs they will replace. Then I'll completly remove the ribs one at a time and slide the new rib over and permanently secure it. I have decided on this course of action due to the fact that the ribs are completely exposed.

I have to take a closer look and determine if the rib is one continuous piece from starboard side through the center "stringer" to port side or if the rib terminates at the center stringer and another piece of wood continues on the oposite side.

can someone tell me what the proper name of the center stringer on the inside of the boat is called and are ribs normaly continuous through this "stringer"?

I sincerely appreciate the feedback from everyone.