Transom Rot or Not?

L

lv2bunderwater

Member
May 8, 2009
128
Chicagoland
Boat Info
86 268DA
Engines
Twin 4.3s
All,

I pulled the old OMC transom assemblies off yesterday to prep for the Merc swap. If you would please, let me know your thoughts on the condition of the transom cavity. It looks okay with only minor cracks and surface rot. The rest of the transom looks and feels solid...

I was planning on letting it dry and injecting "Got Rot", then sealing it to ensure it is good to go.

Thanks for your help!
Transom Cavity.jpg
 
When I found some rot on the 250, I worked as hard as possible to get all the wet and damaged stuff out. I was always under the impression that spores can cause the rot to spread. While you have everything off anyway, I say dig it out and replace as much as you can with some fresh lumber. I used West System products and they worked really well.
I think in the long run you will be happier with doing the extra work. That area of the the transom should be as strong as possible
 
Leave the wood exposed and allow to dry as much as possible. Use a fine drill to bore through the rot just to reach the good wood and use Acetone to soak into the rotted wood allowing for maximum penetration - acetone will displace any remaining moisture forcing the water to the surface where it will evaporate. Acetone will also kill any remaining spores before evaporating itself.

There used to be a product called Calignum that was fantastic for curing dry rot. I haven't owned a wood hull for more than thirty years, but I once had a 21' day sailor that had some rot in the keel. Calignum (a two part epoxy type stuff) was used to repair it. Drilled a couple of holes partially into the rotted wood, one at each end of the affected area and a couple more spaced evenly between. The trick was to pour acetone into the affected area - killed the mold and floated any moisture out (water floats on top of acetone like oil floats on top of water) - after everything dried out, poured the Calignum into the holes untill it wouldn't hold anymore. The bad wood acted like a wick and sucked this stuff up like nobody's business. After it cured it was just like the plastic on a screwdriver handle and stronger than the original wood. Isn't that stuff around anymore?
 
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Did a little searching online and found something called Solignum, don't know if it is the same thing that NJ was referring to but it may work for you.
 
Definitely rot in that area, start digging and see how far it goes. Also while in there, check any areas that may have fasteners below the waterline on the outside. If an area is really rotted you can actually push on the inner shell of fiberglass and feel it flex. Hopefully no surprises.
My project started with the intention of fixing the bad areas. I ended up just replacing the entire transom which was easier and much more solid in the end.
Here is a link to the step by step post I put together - it may help out either way: http://clubsearay.com/showthread.ph...-Restoration?highlight=1985+270da+restoration.

Best of luck with the project !
 
would acetone not possibly cause a delamination in the glass area though ???
just curious because I know it will eat up a limb on a compound bow....long story...don't ask.
 
Acetone is used heavily when preparing fiberglass and wood during boat repairs. It cleans, dissolves water and drys with no residue left behind.

Acetone is a fiberglass guys best friend.

I'd be digging into that transom and fixing everything while you have the engines out.
 
I vote with Getaway... he did a great job on his 268. Better then factory for sure... now is the time to handle the problem hopefuly it is a small easy area. Best of luck!
 
Thanks to all for the feedback. I figure I will clear out all the rotted wood and use Acetone to prep for epoxy filler. If the area is big enough, I will epoxy in a wood plug due to it being located right at the transom assembly bolt holes. I will take pics of the finished product.

Thanks again!
 
Hello all,
Okay, enough procrastination on my part… I started on the transom tonight clearing all the wires that were attached. I plan to prep during the week and start cutting this weekend.
I tapped all around the stringers and everything seems to be fine. I am so hoping that it is only the transom that needs to be cut out and replaced. Thanks to some of the threads here, I believe I have all the tools I need to start digging into it. I plan to make some wiring changes while I’m at it by relocating all that I can to a central control board located in a convenient area. Also, look to relo the main battery switches to be above the engine hatch on the deck somewhere.
Another item I have been thinking of is relocating the hot water tank to the port side. These classic Sea Ray have a noticable list towards starboard, so I hoping to help correct that by moving the hot water tank to port side. My only fear is if I will have enough room for the port trim pump.
So, I will start cutting this weekend. I’m very nervous about the stringers and the center motor mounts. Because I have twin screws, I do not want to rebuild the center motor mounts. That would be a royal pain in the butt.
Cheer me on please…
James
 
Good luck to you! Take lots of pics.


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I've often wondered about using StarBoard instead of plywood for the transom wouldn't have to worry about rot ever again.

Maybe weight, stability? Wonder if anyone has ever tried it
 
I don't think that would be a good option. Starboard does not have enough strength / stabilty and would not bond well with the fiberglass. Added weight would also be on the down side. I looked into fiberboards available when doing ours but cost goes up substantially; finding marine grade plywood to be the best all-around option. I figured it worked for 25 years with plywood and water penetrating due to lack of maintenance and improper sealing so I should get much more than that out of the rework. Sealants are also much more reliable than they were back when the boat was initially built. Just my thoughts.
 
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I started digging out the rotted transom. I am glad I decided to replace instead of just tryng to repair the rotted area next to the starboard cut out. Notice the black area near the drain. That area is completely wet and soft. I'm still hoping the stringers are solid.

Transom%2520Wet%2520and%2520Rot%2520041512.JPG
 
Good choice, I was initially thinking the same with ours - just fix what's bad. It ends up much easier to just replace it all, stronger too.
Keep posting pictures of the progress and best of luck. :thumbsup:
 
That looks so eerily familiar...

Best of luck. You have a great boat that's worth the efforts.
 
Thanks! I hope to have the transom cut out and sanded by next weekend. I will then start working on the replacement transom. I'm planning to use Marine Plywood (1"). I have read the Pros and Cons regarding marine grade plywood verses exterior grade plywood. Other than the associated costs, there are no down sides to marine plywood.
 
lv2bunderwater said:
I'm planning to use Marine Plywood (1").
Click to expand...

Just a note - it's important to maintain the original thickness of the transom so your rear engine mounts end up in the same place.
Taking ours down to the outer fiberglass required 1 1/2" so I laminated (2) 3/4" pieces of marine grade together.
Don't need any surprises when you start putting things back in.
 
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