Transom Rebuild - The Saga Begins

[Fishtales]

Yes, I agree. It corrodes galvanized steel as well. Recently had to swap the joist hangars on my deck (I kept the structure but did vinyl decking and railings) when I re-did it.
I'll be sharing findings and results as this unfolds.

 

[Fishtales]

Engines are off the boat. Took less than a day and they are away in storage. Here are some pics of the starboard side. The bulge is just below the bang plate. It is approximately 1.5"in height and 3" in length. It really does not protrude that much at all. It is hard to actually detect.

 

[Fishtales]

Here are the 2nd set of pics of the port side. The bulge is very small (smaller than the starboard side) maybe 1"X2" in size. Looking at it, one may say that isn't anything at all.

 

[Fishtales]

The boat is ready to go to the glass shop tomorrow. I figured I'd drive over and meet the guy face to face as up till now we've only communicated via email and phone. I spoke with the glass guy and got the low down. He indicated I will be shocked at the level of damage when he opens up the boat. Water makes it's way in and the 5/16" aluminum brace, the water and the Greenwood XL treated core start a chemical reaction and a gel like substance forms. This gel pushes against the brace and the glass and forms a bulge. Freezing temps make the situation worse. If you are observant, you will detect the small bulges near the bottom of the bang plate on the backside of the transom.

 

[Fishtales]

You can see, I've been on top of this issue as the rotten transom stories were burned into my brain on The Hull Truth website with threads written by a guy in NJ called Jawz or Jaws. He had story after story of pre treated wood transoms where the wood literally turned to mush. Later some stories with the treated Greenwood XL board. He was always arguing with GW owners that had new boats and couldn't believe this stuff was true (self included in that bunch although I never disputed his threads).

I sealed the bang plate and the plastic pieces used on the edges of the motor well from time to time hoping to keep water out. To this day, I fail to understand why anyone would drive fasteners into the core in this area, why the caulked seam isn't glassed over and why there isn't some sort of alert or preventative action recommended. There are the brass tubes and transom flaps that cover them on the transom with another 3 screws on each. Yep, driven through the glass into the core.

The bulge area is about 4" above the water line and during use water is always washing over into the motor well and draining out. Seems like the perfect combination to ensure water penetration into the core of the transom by design.

 

[Fishtales]

Engine mounting holes look solid and there was plenty of sealant around the bolts. It doesn't appear that there was water intrusion in these locations. We'll know for sure when the transom is opened. If you recall, I had the mid sections of the motors done and as a result they were off the boat about 5 years ago. If I have to guess, water got in under the aluminum bang plate where the hull/liner joint resides. I'm starting to wonder if the bang plate is to protect the transom during engine install or to cover up? You can see the bang plate corroding in places. Good to see this is a phenolic bang plate today.

Not to be a Debbie Downer, but from what I understand, this isn't a problem you MAY get. It is not an IF, it is a WHEN for many of us. I saw two more boats in the yard for the same issue. Needless to say I'm pretty sad at this point as this likely is going to be expensive to rectify.

 

[seasick]

Did you happen to have had a moisture test taken prior to removing thingd? I am currious if that would have given a hint as to the point(s) of water intrusion.

 

[seasick]

Yes, I agree. It corrodes galvanized steel as well. Recently had to swap the joist hangars on my deck (I kept the structure but did vinyl decking and railings) when I re-did it.
I'll be sharing findings and results as this unfolds.

The corrosion of the joist hangers was not caused by CCA treated lumber. The problem arose when CCA was banned and new wood was treated with ACQ. In those cases you needed heavily galvanized hangers or stainless hangers. As far as I know, ACQ has been replaced with MCA treated lumber which is less reactive with steel.( but still needs hangers approved for it.
Regardless Greenwood XL was CCA treated and held up quite well in transom applications , better than marine ply. It will get wet in water but it won't rot or turn to mush coring of end grain balsa can.
In your case without actually looking at the core, I would agree that the damage may be due to freeze/thaw cycles.
If I were redoing the transom and the wood was delaminating on the inside of the transom, and I was going to cut out the outside of the transom, I would cut out the wood and recore with a composite like Coosa board.

 

[magicalbill]

Fish:

This is technical stuff I don't relate to or understand.

I am therefore sending good wishes and a reasonably priced and (hopefully) quick fix for you. Certainly sorry you have to wade thru this.

Best! Magic....

 

[igblack87]

I myself will also send tight lines and best wishes your way. Hopefully the transom inst as bad as thought to be. Hopefully it is just the spots you are concerned about and a new bang cap that need replacing.

 

[efx]

Please take some photos once the outside fiberglass is off. I am very interested in the condition of the plywood. I have a sense it will be black but it will probably be solid.

One question: was there any deflection of the transom when loading weight on the motors?

 

[Fishtales]

No deflection of motors that I observed. No moisture readings taken.
Don't know about the PPT chemistry but original deck was built in 1990 and the wood structure was superior to new wood. The hangars were shot though.
Thanks to all, we'll get it done.

 

[Marbles816]

I went through it two years ago. I ended up redoing the entire transom and glassing it completely closed. Make sure you address the brass through hulls in the motor well. I had water entering there also because one of the brass fitting had cracked. Youngs Fiberglass did my boat and I am extremely happy with the outcome.

I agree! Young's is great. They did my transom year ago too. And Dan is a nice fella to work with.

 

[drbatts]

Just out of curiosity did you contact your insurance company and what was their take on this?

 

[Fishtales]

I did not contact my insurance co. I would have if it were due to an accident, but just like your car breaking down I don't think insurance covers a defect. I have notified GW and presented my case. Hoping they will stand behind it. We'll see.

 

[Fishtales]

I agree! Young's is great. They did my transom year ago too. And Dan is a nice fella to work with.

Yes we are planning to address the drain tubes and whatever is needed on the transom. It could be 6", maybe 8", maybe the whole thing depending on what is found. He indicated the large cap that the factory installs will be eliminated and the glass will come over the entire transom. He showed me pics of other boats he did this way. Any transom work will include the composite coring and the aluminum brace will be taken out, completely reworked, painted and then encapsulated so it is isolated from the Greenwood XL coring to eliminate the risk of a reaction between the metal and treated wood.

 

[igblack87]

Will you be documenting the process when your boat gets to the fiberglass shop? I am eager to see what it is like, what kinds of decisions are to be made & if your situation could be a good reference point for others with potential similar transom concerns.

 

[seasick]

Yes we are planning to address the drain tubes and whatever is needed on the transom. It could be 6", maybe 8", maybe the whole thing depending on what is found. He indicated the large cap that the factory installs will be eliminated and the glass will come over the entire transom. He showed me pics of other boats he did this way. Any transom work will include the composite coring and the aluminum brace will be taken out, completely reworked, painted and then encapsulated so it is isolated from the Greenwood XL coring to eliminate the risk of a reaction between the metal and treated wood.

Now that's a good plan! I look forward to progress photos.

 

[Greatty]

Thank you for the update Fish. I have a 99 180 and have similar concerns. I am curious as to what the inside of your transom will look like but hoping for the best for you.

 

[georgemjr]

Thanks for keeping us up to date and good luck with the repair. An FYI to those thinking it is the freeze cycle: Although I am sure it can exacerbate it, my friend in Florida, with a lift kept boat has the problem as bad as any I have seen, so it doesn't require freezing. When I removed my bang plate there wasn't enough caulk to even think about sealing 9barely a bead) and the bead wasn't smushed from making contact, so no seal at all from the factory.