# Transom Wood Replacement-UPDATE!



## fish4thriLLs (Sep 18, 2011)

Well, it looks like I may have a winter project. I recently found a small soft spot in my transom wood. It looks like it's gonna be a real challenge fitting a new one piece wood board into the same spot as the original wood, but it's gotta be done.

I have never done a transom overhaul before. I have a buddy of mine that's getting me a white oak board that's 1.5" thick, 12" wide, and 70" long. This is about what my existing transom wood measures. 

My main concern is, how in the heck am I gonna get my new one piece white oak board into that same area as the original board?? The transom area is angled from shorter at the bottom to longer at the top and has braces, brackets, rivets, screws and everything holding it in place. #-o 

Do I need to try to install my new wood as a one piece unit or can I cut it into two or even three pieces to ease the pain of getting it in there? Do I bend the braces/brackets back out of the way or remove them completely and replace the rivets with stainless screws and then reinstall?

Is the white oak board a good choice as replacement wood or is it too heavy? How do I treat the wood before installation?

I have posted pics below of my existing transom area.. Any ideas on this will be most helpful and I really appreciate your thoughts.


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## PSG-1 (Sep 18, 2011)

You may even want to look into using some type of composite board to do this with, then you only have to do it once for the lifetime of the boat.

And yeah, it's a PITA to change that board. You're going to have to systematically dismantle that transom, remove bracing, bolts, etc. and then put it back together. Without standing at the boat and seeing it for myself, it's hard for me to advise you as to the exact process for doing it. 

But it appears that if you can somehow remove the bottom lip, you should be able to tilt the bottom of the board out first, and remove it. Install the new one in the reverse order. The only problem may be in how you can remove that bottom lip of aluminum, you may just have to cut it off, then replace it with a piece of aluminum angle, using some bolts.

In my 15+ years of welding, I think I've replaced a total of 2 transoms. But when I do it, I take a skilsaw (yes, you can cut aluminum with one, that's one of the nice things about working with aluminum, no special cutting equipment required) and I cut off the cap, and then make a new one out of 1/8" plate, bending it in a metal brake. On one of them, the guy had a huge piece of plastic composite similar to 'star-board' and we replaced the wood with that.


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## lckstckn2smknbrls (Sep 18, 2011)

I removed the corner caps and straightened the top cap to slide the new transom wood into place. Then I lightly hammered the top cap back into place and had the corner caps tig welded back on.


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## fish4thriLLs (Sep 19, 2011)

I think I might be able to straighten out the bottom lip and the side brackets, but I'm afraid of the knee braces that are connected to the bottom of the boat and then connect to the transom. I don't see how I can get around them once I take the bolts out of the top of them where they connect to the transom. They are made of steel, I think. Am I gonna have to drill the rivets out of the braces where they connect to the bottom of the boat?? I think I could go in from the bottom of the transom with the wood if I could just get around the knee braces.

Anyone have any better ideas?


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## Ictalurus (Sep 19, 2011)

fish4thriLLs said:


> Anyone have any better ideas?



F4T, I feal your pain as I had the same issue with my Landau. The transom wood was shot, and it was also enclosed by riveted aluminum on 4 sides, just about the same as yours. I chose to drill out all rivets holding the transom in, was a pain but worth it. My new transom is two 3/4" oak plywood boards stacked together (1.5"). Instead of one 1.5" piece of wood, try using plywood, it is stronger. I put stainless steel screws in place of all the old rivets, #10 size screws are super close to the 3/16" rivets that held the old transom in place. I just recently finished, so no long term report, but so far so good. I've attached some pictures to illustrate my rambling. Edited to add that I used 3M 5200 on all screws.


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## fish4thriLLs (Sep 19, 2011)

Very nice work, Ictalurus. You are right, yours is very similar to mine. So you think I should drill out all the rivets, even the ones holding the knee braces to the bottom of the boat? That's kinda scary but it looks like that's the only way.

I'm hoping the one piece solid white oak board will work because I've got a buddy that's already gotten one for me. It's 72" X 12" X 2" now but I will let it dry some this winter and then have it planed down to 1.5" thick. Do you think it will be strong enough? Should I use a water proof finish of some type on it or just paint it?

Thanks everyone for your comments/ideas. Keep'em comin'.


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## Ictalurus (Sep 20, 2011)

fish4thriLLs said:


> So you think I should drill out all the rivets, even the ones holding the knee braces to the bottom of the boat? That's kinda scary but it looks like that's the only way.



For me, it was just easier to take them out, rather than trying to bend them back to put the transom back in. Seems like I'd have to flex them too much and was worried that would do more harm than just removing them. One tip for you, I didn't have to drill every rivet, I have a set of big wire cutters (at least that's what I call them, probably actually something else) that would take the rivets off pretty easy, then I just used a hole punch and popped them through. As far as the wood, it's up to you and what you have would probably work just fine. I've just been told that several boards glued together were stronger than one piece that was the same thickness.


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## fish4thriLLs (Sep 20, 2011)

Great info so far guys. Thanks for the ideas!


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## Hanr3 (Sep 20, 2011)

fish4thriLLs said:


> I'm hoping the one piece solid white oak board will work because I've got a buddy that's already gotten one for me. It's 72" X 12" X 2" now but I will let it dry some this winter and then have it planed down to 1.5" thick. Do you think it will be strong enough? Should I use a water proof finish of some type on it or just paint it?
> 
> Thanks everyone for your comments/ideas. Keep'em comin'.




White Oak is your best option. Naturally it will withstand the elements for decades. It is super strong and will withstand more abuse then your boat motor could dish out. If you dont have a thickness planer and want to save yourself some cost, route out the edges to the thickness you want, leave the rest 2" thick for added strength. 

Stain, outdoor polyurathane will make it look beautiful and protect it a little longer.


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## fish4thriLLs (Sep 20, 2011)

Thanks so much everyone. I feel more confident about finishing this project, now that I have some good ideas :idea: from experienced boaters.


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## fish4thriLLs (Sep 23, 2011)

*UPDATE*

My white oak board wasn't wide enough so I gave it back to my buddy. He said he would get me another piece. Man, that oak piece sure was HEAVY!  I wonder how much the weight would affect things if I use the oak? :? 

Now, I'm considering using two pieces of 3/4" hardwood plywood, as was mentioned earlier.

What are some of your thoughts on which kind of wood to use? #-o


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## Hanr3 (Sep 23, 2011)

plywood will rot in a realatively short time frame, 5 years or less unless you go pressure treated, in which case the treatment will eat the aluminum in about the same time frame. Marine grade plywood only means they use water resistant glue and there are no voids, will still rot in about 5 years, longer depending on the protective coating. Exerior grade plywood would last, however its full of voids, thus a good wake and your motor could crush a void, next wake and the motor could fall off. Even if it didnt fall off, your left replacing the wood again.

White Oak is your best option unless you want to sacriffice durability.


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## dieselfixer (Sep 23, 2011)

Back in the days of wooden sailing ships oak was the wood of choice. I would use oak and then coat if with several coats of marine varnish. Oak looks very nice to.


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## jgilbo17 (Sep 23, 2011)

i have this very same problem and was gonna use pressure treated plywood but this oak sounds better


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## fish4thriLLs (Sep 23, 2011)

What about the weight issue of white oak? I mean this board is HEAVY! But, of course, it's 2" thick and 74" long too. The next board I have coming will be even heavier since it's gonna be at least 12" wide. After I plane it down to 1.5" thick and about 69" long it'll be a little lighter but, still it's gonna be uber heavy. Will the weight cause me any problems? My boat's specs are in my signature below. I have tiller steering and I recently moved my battery to the back of the boat. My 6 gallon gas tank is back there with me also. I don't have any decking installed. I've never had a problem with my boat sitting too low in the back. But, I haven't had my battery and a huge chunk of white oak back there before either!


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## jgilbo17 (Sep 23, 2011)

i would think the weight of the oak is minimal compared to the weight of a 40lb battery's placement, i wouldnt worry aout it


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## Hanr3 (Sep 23, 2011)

There are places to save weight, and this isn't one of them. Transoms ain't cheap to replace.

if weight does become a concern, mover the battery forward.


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## Jdholmes (Sep 24, 2011)

On a side note you should really consider placing your fire extinguisher in a different location...that seems like a useless spot for it.


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## BassBlaster (Sep 24, 2011)

Just wondering, has everyones general rule of transom replacement been changed over the last year? I asked about using dimensional lumber for my transom replacement and EVERYONE said it was a bad idea for various reasons. Check my build thread for those replies.

I went with 3/4" exterior grade plywood per everyones advice. I sandwiched 2 pieces to get my thickness with waterproof wood glue, stained it and put on 3 coats of spar urethane. Every hole that was drilled for bolts was pumped full of 3M 5200. This baby is sealed and there is no way it is going to rot in 5 years. Id be surprised if it didnt last at least 20 years.

For what its worth, I pulled an equipment trailer for 5 years that had a white oak deck on it. That stuff is tough but it expands and contracts A LOT with the weather and gets very brittle after several of these wet then dry cycles. This is an untreated deck though.


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## Mojo^ (Sep 24, 2011)

I used two sheets of 3/4 exterior ply laid-up at 45 degree angles and bonded together with PL. I sealed the whole thing using epoxy resin from U.S. Composites ensuring that all voids and drain paths in the ply were filled. Fastener holes were piloted and then drilled oversized. The oversized holes in the ply were filled with a mixture of epoxy resin, cabosil and phenolic microballons. Once the transom was reinstalled, I drilled the fastener holes through the potting mixture in the holes and installed aluminum fasteners using 3M 5200. While it may be overkill, this transom core will likely outlive me.


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## Hanr3 (Sep 25, 2011)

My boat was built in 1967 and I replaced the original transom 3 years ago. The original white oak board was 40+ years old. IT had one small soft spot under one of the plates, both of the screws in the corners had broekn off making repair next to impossible, and looked like crap. Structurally it was still rock hard.

The plywood piece on the outside of the transom was completely shot. I replaced the plywood with more plywood. I've pulled the motor a few times, there is a visible difference in the amount of wear to the plywood and white oak. The white oak has the stain/polyurathane removed, the plywood has grooves plus the stain/polyurathane removed. No matter how well you treat the wood, that treatment will wear off under the vibrations of the motor, thus exposing raw wood to the elements. White oak naturally will outlast plywood.


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## Ictalurus (Sep 26, 2011)

BassBlaster said:


> Just wondering, has everyones general rule of transom replacement been changed over the last year?



Bass Blaster, I'm in 100% agreement with you. This must be the first post I've read that said to go w/ solid wood over plywood. I'm still pretty sure that the plywood would be stronger, as glued pieces are stronger than one solid piece. My new transom is two 3/4" ply, and unless I leave it submerged or outside, it will be going strong in five years and probably still in 25 years.



Hanr3 said:


> I've pulled the motor a few times, there is a visible difference in the amount of wear to the plywood and white oak.



Hanr3, apples and oranges here, one piece is on the outside!


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## Hanr3 (Sep 26, 2011)

Ictalurus said:


> BassBlaster said:
> 
> 
> > Just wondering, has everyones general rule of transom replacement been changed over the last year?
> ...



Why is that apples and oranges? 

Point is, white oak has been used in the structural elements of ship building since the first ships were built. Its not a new concept, the use of plywood in ship building is a new concept. The white oak can be submerged and left outside for decades and not rot. Plus white oak has tannins that repeal insects. Typically plywood is made from inferior grades of wood, ply's can be full of voids, and the glue could delaminate when wet. In order to get a white oak comparible grade of plywood, you need void free, water resistant species wood, and water resistant glue. Read big bucks and your typical home improvement store doesnt carry it. Finally, when you compare costs, you will find White Oak will be more cost effective. Now if you rarely use the boat, store it inside and under cover, plywood may be your best option. 

https://www.gazela.org/ships/gazela/hullplanks.html

Pretty sure Christopher Columbus crossed the ocean on wooden ships, and there wasn't an ounce of plywood in any of them.
https://www.pjstar.com/news/x909199815/Replicas-of-Nina-and-Pinta-arrive

What can I say, the replicas stopped in my town this weekend.


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