Transom doubler replacement coming along...

[Erieau]

Hi gang. Long-time lurker, first-time griper. I just have to complain to people who'll understand.
Transom-backer replacement is on the long list of repairs to my "not supposed to be a project" 25. It's what I'm doing today, squeezed under the cockpit with my Tazmanian Devil grinder.
The fully-delaminated inner fiberglass layer came away easily after dremelling away the perimeter, and the gudgeon-backer wood was entirely black mush. The larger area behind the motor mount wasn't as badly rotted, but had clearly never been properly adhered to the transom skin at the factory: only a couple thick gobs of bondo-like substance were actually joining the wood to the hull (mostly just an air void in there). No wonder the transom flexed so much.
Anyhoo, I've got the 'glass scuffed up, ready for a new doubler. Need to cut a cardboard template, then make some more sawdust.
Many thanks to you who have posted about transom work in the past. The search feature is my friend.

Joe

 

[Joe11688]

Hi gang. Long-time lurker, first-time griper. I just have to complain to people who'll understand.
Transom-backer replacement is on the long list of repairs to my "not supposed to be a project" 25. It's what I'm doing today, squeezed under the cockpit with my Tazmanian Devil grinder.
The fully-delaminated inner fiberglass layer came away easily after dremelling away the perimeter, and the gudgeon-backer wood was entirely black mush. The larger area behind the motor mount wasn't as badly rotted, but had clearly never been properly adhered to the transom skin at the factory: only a couple thick gobs of bondo-like substance were actually joining the wood to the hull (mostly just an air void in there). No wonder the transom flexed so much.
Anyhoo, I've got the 'glass scuffed up, ready for a new doubler. Need to cut a cardboard template, then make some more sawdust.
Many thanks to you who have posted about transom work in the past. The search feature is my friend.

Joe

Joe,
I can understand your pain and I really don't blame you for griping because I would dread having to get into that tight area and beef up my transom but I take my hat off to you for addressing this problem head on right now and not putting it off. This work you're doing can save your life and the lives of your family.

A few short years ago one of the guys on this forum had his transom stove on his O'Day 25 when his four stroke outboard accidently over accelerated in forward gear. Thank God the damage done to his transom was above the water line or that boat would have sunk on the spot with his family aboard. He posted pictures of his transom and they're probably still in the archives on this site. Oddly enough, the engine was mounted on a regular two stroke bracket which sustained no damage whatsoever. Go figure!

My friend Wayne just beefed up the outside of his transom with stainless steel bars. He has a Seaward 22 with a 9.4 Tohatsu four stroke outboard. His transom is beefed up inside with StarBoard and metal backup plates and there's not much room in there to work. There's probably a 2 or 3 inch space in there. Mine has about 4 inches of space to work in.

All I can say to you Joe is take your time, do a good job and you'll never be sorry later on.
Joe

 

[glong3]

Joe,

I am about to do the same thing to my boat. Are you going to replace the rotted area with plywood or are you going to use foam coring in that area? If you have the ability (and space under the cockpit) to take pics of the repair, I would like to see them so I know what I am in for.

 

[Erieau]

glong3,

After making the giant mess under the cockpit last weekend, I installed the new plywood today. I cut the pieces last Sunday and 'glassed the inboard faces while out of the boat. I say "pieces" because the gudgeon backer is thicker than the engine backer, so I went up from 1/2 to 3/4 there. Plus, the engine-area backer barely fit down in there even on its own.
YMMV, but here's how I did it:

Using a fibre-reinforced dremel disk, I cut around the perimeter of both backer pieces. The skin easily fell away once released.
The badly-rotted gudgeon backer came out mostly with the shop vac: mush.
The juxtaposed engine backer took a little persuasion: a chisel, shoved in behind from the transom centreline, simply popped it off. It was only adhered with bondo, and that in only a few spots: most of the backer wasn't in contact with the transom.
Using a sander flap-disk in my angle grinder, I took off all the bondo (that's where most of the dust came from) and the fiberglass "flange" that was left from the dremel work.
Transom prep done, I used the old delaminated skin to make rough oversized cardboard templates for the new plywood. I made the new pieces a full two inches smaller in most dimensions, as a big problem with the rot was inadequately glassed edges where the ply didn't quite meet the hull sides and bottom. Impossible to eyeball the side-bottom radius for inspection, too. The edges of the new pieces are cut at 45's and sanded to a smooth contour for good glassing around the perimeter. I also cut shallow vertical grooves in the back side to help the panel conform.
The two-layer (mat-glass) inboard face of the pieces is in polyester, and was easily done in the yard.
A good, unthickened coat of epoxy went on the transom and bare wood, then a mayonnaise mix, nice and thick (12 squirts?) onto the backer.
CAREFULLY maneuvering the piece down through the hatch (I practiced before puttying it up), I slapped 'er in place, holding it there using a screw driven through a predrilled alignment hole. Perfect. I jammed a few hastily-cut cedar shims between the cockpit back "wall" and the new backer.
To the outside of the boat for the painful part: drilling a buttload of holes through the transom. Carefully drilling 2 or 3 1/8" holes at a time only through the fibreglass, I then drove in 2" screws to pull the backer firmly against the transom. There must have been 40 screwheads on the transom this afternoon. Awful to see, but it was the only way to ensure total contact.
With the gudgeon backer installed next, pressed tightly against other piece, I waited for kick.
Couple hours later, out came the screws, in squirted syringe-loads of thickened epoxy to fill the screw holes, and I got working on glassing up the perimeter. Easy-peasy: one layer of cloth strip 4 inches wide, from 1-inch over the plate, right out to the transom edge; then a 1-inch strip of mat to fillet the wood's perimeter edge (very happy I cut at 45 and contoured nicely); then a top layer of cloth same as the first. A strip of cloth up the middle to "join" the two pieces, and we're done.
I WILL be sure to epoxy-seal all holes through these plywood pieces, and I WILL thoroughly bed all hardware. No way do I want to do this again.

Will proudly snap a few pics tomorrow morning, and figure out how to post them here.

Best,
Joe

 

[Erieau]

pics of finished repair

As you can see, the wood doesn't reach into the transom corners, and I thoroughly glassed-down the edges.
The transom exterior looks like a pincushion.

 

[Swee Pea 1976]

Looks good!

 

[jberube85]

Joe just a few quick questions (please be patient as i am new to glass work) - When you said you glassed the inboard side you mean the face you can see from inside the boat and bare wood went up against the transom?
- Then the unthinkend epoxy you just brushed on both transome and wood then put a whole lot of thickend epoxy on just the wood?
- Lastly the vertical lines you cut that was also the bare wood that buts up to the transom correct?

Thanks in advance for the help I am putiing a new motor baracket on my oday 22 and want to do this prior.

 

[Erieau]

When you said you glassed the inboard side you mean the face you can see from inside the boat and bare wood went up against the transom?

*That is correct. I could have done that *after* installation, but sometimes I have these unexplained flashes of genius.

Then the unthinkend epoxy you just brushed on both transome and wood then put a whole lot of thickend epoxy on just the wood?

*Also correct. Unthickened soaks in better as a sort of "primer" coat.

Lastly the vertical lines you cut that was also the bare wood that buts up to the transom correct?

*You got 'er, cap'n. They were shallow kerfs, maybe 2-3 inches apart if memory serves, perhaps 1/8" deep. I cut them vertically, but while installing I discovered that the compound curve of the transom would have been better met with a sort of "fan" pattern: kerfs spaced 1" apart at the bottom and 2-3" at the top. In the end, no matter; the screws from the outside pulled the plywood nice and tight with very little, if any, deformation of the fibreglass skin.

Incidentally, the replacement has held up brilliantly in some very choppy Lake Erie waves. Absolutely no transom flex under power, the gudgeons are rock solid (and no longer leaking), and the transom still looks like a pincushion. I'll paint the thing next winter.
Certainly a worthwhile repair.
Now about all my dang topside leaks...

Joe

 

[jberube85]

Great thanks for the response Joe, I just ordered the west system this morning and going into my days off thursday so hoping to get this done this weekend Ill let you know how it goes and take pictures fo the whole process...

 

[jberube85]

Joe one more question, you did the 2 layers prior to putting it in the boat then you epoxied it into place after that set you glassed just the perimeter with the 4" or did you also glass over the whole inboard face again?

I cant get the rain to stop so I can do this lol but probably a good thing because I figure out a new question every time I read this haha

 

[Erieau]

I did not apply additional layers of cloth/mat after installing the backer. I only glassed the perimeter after installation.
FYI, before cutting the new backer from plywood, I futzed around with the cardboard template for a good long time, getting it just so. It's so much easier to trim cardboard than plywood.
You'll also note that I used polyester resin, rather than epoxy, on the inboard face. This was only because I have a gallon can of it kicking around, not because I thought it's superior for the job. Epoxy would have been a stronger bond, especially to wood, but it's just the mood I was in at the time.
Hope the rain clears up for you. We had a few days of it this week too, and the weeds really appreciated it.

Joe

 

[jberube85]

Thanks Joe for all the help I started today! It took forever to get the old motor bracket off because the guy before me put one of the carriage bolts in from the transom out and the nut was rusted on so i had to cut it with a dremil. then for the kicker the old bracket has a adjustment to offset the transom angle and the new one doesn't so back to home depot to get some more wood to make a tapered wedge to glass into the outside of the transom i went lol. so I got the backer inboard face cut and glassed. then of course there is no stock wood sizes that will work for what I need to make this wedge so I got a piece of 1"x11 and cut three pieces and epoxied them together and tomorrow I will plane them down to the correct angle. I took a bunch of pictures but I need to get the girlfriend fed or she is going to kill me so more to come later or tomorrow

 

[jberube85]

hey guys here is a blog I started that has all the info on this project and others!

http://mysailboatproject.blog.com/

 

[Erieau]

Good idea on making the wedge; I need to do that this winter. I thought I could do without the old cracked wedge, simply by remounting the engine mount lower on the transom than it used to be. Well, the outboard's water intake isn't quite low enough for my liking. Live and learn.

 

[peterbud]

I made the same bracket for a 222 out of AZEK the difference you never need to worry about it having any kind of water damage. The AZEK can be worked like wood and it can be glued.

 

[RichBone]

How did you get the old wedge off?

 

[Erieau]

How did you get the old wedge off?

Mine fell away with the motor mount. The adhesive had long ago lost its grip.

 

[jberube85]

I didnt even have one on my boat! Finished the wedge today and it came out pretty good i think just have to mount it on the boat now. Pics tommorow on the blog...!

 

[anchorclanker]

Okay, getting depressed seeing these pics..

So the gudgeon's and motor mount have wood filler within the fiberglass layers, and its rotted out? I can access the port side through the lazarette, but not sure about the starboard side, unless the bulkhead to the cabin comes out.

Some day ill find a trailer to bring her home so I can work on it. Ive pushed the motor mount around and it appears pretty solid, ill keep an eye on it.

 

[Erieau]

My wedge fell right off with the motor mount; the adhesive had long since lost its grip.
Anchorclanker: if the transom doesn't flex when you're under power or when you force it side to side, then the plywood doubler is probably fine. You could always draw a core sample (from the inside) to have a look at the wood, or just dremel off a small section of fibreglass to have a look. I generally only fix what's broken, and my transom definitely needed fixing.