268 weekender transom rot (contains high resolution pics)

Yes sometimes the 'core' between two layers of glass is going nothing more than keeping a shape, but in this case the stringer is carrying a lot of load as well. The glass and wood core work together to make a piece that is stronger than one made of a single material. Wood has different strength properties in different directions. For example, stand a piece of wood so that the grain runs vertically and you can pound on the end and drive it into the ground. Take the same piece of wood and place so the grain is parallel to the ground, hit it with the same tool and force and it will be splinters in no time.

The engine mounts are going to see a lot of force being directed on them (engine weight, plus all the engine torque and vibration). The pine stringer will split under load. What you want is a nice dense wood like oak

Also your existing stringers got wet (oak turns black when it gets wet), but they are still here after 20 something years. Get water under the glass and the pine board will turn to mush in a couple seasons.

Try and get a copy of Wooden Boat Magazine. Mostly sailboat construction is covered in the articles, but there are a number of reputable wood suppliers that cater to the boat building industry that advertise.

Henry
 
I have just checked back in on your progress - very nice work. :thumbsup:

" I thought the glass actually provided the strength? "

Your right with that statement regarding the stringers under the engines. The wood is basically a filler. Some of the new boats are even using a foam core.

I too agree with laminating 3/4 inch ply. It seems it would be easier to shape, stronger and less expensive.

You may already have this in mind but I suggest using this Bi-latteral fiberglass for the stringers too - can't get any stronger. Far less layers needed for thickness too.

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Bi-Lateral Cloth. Consists of a fiberglass matte sewn to a fiberglass cloth. (copied from my replacement post)

Keep up the great work !!!!!!!
 
All the wood was black. Even the plywood in the transom. My goal is to this so that it lasts. I will c about finding oak. If not i'll just laminate 3/4 ply together.
 
lime4x4 said:
All the wood was black. Even the plywood in the transom. My goal is to this so that it lasts. I will c about finding oak. If not i'll just laminate 3/4 ply together.
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If you're going to laminate, see about finding something other than 3/4" ply. Try finding some sort of hardwood. The problem with ply is that it will wick water in more easily vs. a solid wood.

Doug
 
the bilge is all clean and ready for new transom and stringers. Then i found some rot in the mid berth. So now i'm removing the rotten wood and water loged foam. I'm hoping it's not into the cabin area. Really didn't want to rip the cabin area apart
 
Lime - Take one of your stringers to the Woodcraft store in Allentown. Most Woodcraft stores have a "classroom" in the back. These are usually fully equipped wood shops.

Take your stringer into the store and tell them that you need to make 2 of them out of white oak. chances are, they can supply the wood and help you out in constructing them. They may need to special order stock over 1" thick. My local Woodcraft carries only 4 quarter stock, which in reality is somewhere around 7/8" to 15/16" thick in rough milled form. By the time you get it milled to usable dimensions, you end up with 3/4" thick boards. If you get properly dried boards, you can laminate 3 of them together using epoxy or another waterproof wood adhesive and end up with a 2 1/4" assembly that could be planed down to 2".

You will need proper woodworking clamps if you are going to laminate 3 boards together in a glue up. You need to apply sufficient pressure or the lamination will not be as strong as it should be. Do it properly, and it will be as solid as any single piece of wood would be.

If they can special order some 10/4 (10 quarter) stock as wide as your stringer is tall and a few inches (6 minimum) longer, it would be approx 2 1/4" thick after you milled it down on the jointer and planer. You could remove the extra 1/4" if you wanted, but I would leave it that thick if it fits in the space without causing any problems.

You might also want to check out Woodfinder for locating a "real" lumber yard. Bailey Wood Products is close to you, and according to their site, does custom milling. I'll bet if you went to them and asked, they would duplicate your stringers for you. It looks like a 10 minute job on a band saw including cleaning up the band saw marks and prettying them up.
 
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Thanks for the tip. My local lumber yard can get me oak planks. I'm lucky in that i have alot of woodworking tools. table saw,planer and a jointer and about 10 other neat tools. I will check out those places. I would like to get one solid peice if i can. But if not i will laminate peices together with epoxy.
 
A local saw mill can make you any size you need, usually very cheap.
 
Yes, they can. This brings up the question as to whether or not wood for stringers needs to be kiln dried. Wood fresh off the mill has a fairly high moisture content. Typically, it is kiln or air dried before being used for furniture or construction. A lower moisture content is required for furniture, and higher in construction materials. Both are generally dried to some degree before being used.

Enclosing it in fiberglass may negate the need to dry it since no air can get to it, and the existing moisture can't get out.

I do not know the answer, but I would find out if it is necessary to used dried wood or not before building your stringers. Otherwise you could have movement (twisting / warping / shrinking) of the wood as it ages. If you can't find the answer, go with a wood store that caters to furniture builders and buy dried timber. If you keep it dry, it will maintain whatever shape you give it forever.

Glad to hear you have all of the necessary tools, lime. I was checking out your pictures and wondering how you were set up. I'm impressed with your progress. At the beginning where you were showing the rot my stomach was turning. By the time I had gotten to where you have the shell all cleaned out I was feeling much better. I'm sure that you are much relieved as well. You see a new beginning, instead of a cruddy, rotten, end. Nice work. Best of luck.
 
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Yes the wood should be dried, I wasn't suggesting to use it right off the mill, only that dimensionally, a saw mill can make odd sizes.
 
Should the stringers be epoxied to the hull or should something else be used for bedding of the stringers and bulkheads?
 
I haven't done this, but I have done enough engineering on high torque engine installations to know that you want the engine to have a good solid foundation. So my reaction would be that you do want to have more than the fiberglass covering holding the stringers onto the hull. Whether you epoxy them directly to the hull, or use an intermediate layer of glass and epoxy would depend on the situation.

I guess the answer is you have to work backwards from the engine. When you are done you want the port and stbd motor mounts to be the same height and with the proper orientation. On my 496 that means the mounts sit vertical. On your engine they might sit angled in towards the engine. For that you sould check in the installation manual of your motor if you didn't make a note of it during disassembly. The stringer should be adhered to the hull, but to get the proper elevation you may have to do some minor surgery to the hull and build up a support pad with cloth and resin. No matter what way you go it is important that the stringers be in contact with the hull uniformly to prevent stree points.

Henry
 
Air temp 27 deg. With the help of a propane forced air heater. I was able to get the fiberglass temp up to 65 deg and the air inside the boat around 85 deg. Actually had to shut the heater off while mixing the epoxy so that it wouldn't kick off too early.
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Got the some of the bulkheads layed out. Got the engine stringers layed out as well.
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Man, this is really a labor of love, huh? I give you a lot of credit, working throughout the winter cold and all. Thanks for sharing all the gireat photos. Looks like the project is going really well! :smt038

Mooner
 
I like the cold. So working in it isn't a problem. I'm still tossed about drain holes. My bilge is made up of 2 shelves on each side of the engine. My thoughts are if water gets under the shelf which is foamed by the way. Water can also get in thru the drain holes.
 
That is one major under taking you are doing I don't I would tackle it at my age. There is a company by me that will replace the transom for $2000 which seems like a good price for all the work involved. Yes water could get in through the drains but then it would come back out. I think the main thing is that you don't trap any water in pockets along the stringers. I haven't looked at mine real close yet due to the short time I have had it but I know on my Formula there were drain's about every 2' going under the stringers.
 
Once i get all the bulkheads finished and top of the shelves made up i will decide about drainage. The way i look at it currently the boat lasted 23 years without drainage holes. But if the boat is done right there should be no water getting into those area to begin with.
 
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