And yes - there will be a video about the complete transom replacement project coming soon!

Your video is what I’ve been looking for. It’s not just the money either. The time some folks are spending doing this is weeks after waiting for things to dry. I can change out 2 or 3 over the course of 40 years and still come out way ahead on time spent compared to more expensive options.

I replaced a transom with 3/4 inch marine plywood in 1989. I slathered it some water repellent oil/varnish then discovered I needed another board, but 3/4 was too thick. I went with 1/2 inch plywood slathered it in the same water resistant oil. If I'd known to glue them together, I wouldn't have been able to get the boards in. Fortunately for me my ignorance protected me from wasting time, supplies and money. I fit the marine ply wood board in first then the regular plywood. Clamped them to the transom and drilled through the hole from the prior transom. In 2019 it was looking bad so I replaced it again, only to discover the marine plywood was still in great shape! 30 years is an acceptable life for a transom. Loved the video, I'm doing another transom on a 1982 lowe I just bought.

This was a great breakdown of cost vs. gain benefits. For replacing my own transom this season, I also went with the plywood option because of its low cost and made it water-tight with a few coats of Flex Seal.

I've done a few, transoms on my old mid fifties Lonestar Cruise Master, learning as I went. I used three layers of exterior plywood plus fiberglass mat and resin to support the old "Fat Fifty" Evinrude. That got me about fifteen years...which was probably about five years in sketchy shape. I replaced it again, same old lineup but trying to be better with doing the fiberglass and treating the through hull penetrations. I thought that would last better the second time around. The boat ended up in Oklahoma with my son who never actually took it out, so about fifteen years on the trailer I just picked it back up. As she sat, I had to remove the engine before towing it back to Texas for the next round for fear it would fall off if I didn't. (newer engine, 76 HP) . Turns out if one is not careful, water can find a way in between the fiberglass and you get mush. Looked like someone fiber-glassed paper-mache. (which would not be a good idea either.) So, I am taking a hint from my other old boat, a 67 24' Chrysler Cruiseliner with a shop built marine plywood painted transom with fifteen years on it and still sound as can be. Thinking back, I had a number of small wood boats, all vintage, with original wood transoms after decades of use that were still solid. When I do the replacement for the old LoneStar, it will be marine ply. painted or Coosa if I win a lotto:). I know...mistakes were made, but this time I plan on building a transom that will outlast me. Not unrealistic as I am 71 sooo, I will find a balance between budget and solid construction.

This is a great experiment. I look forward to the results. I think it will hold up. On my 12' aluminum boat I used small pieces of oak just a bit larger than my motor and sealed them with spar urethane. Two years in so far so good.

First off, I really enjoy Wayne's videos. I went through the same research as Wayne to replace the transom on my 1989 Grumman Cartopper 14 that I bought last summer. I also went with exterior grade, non-pressure treated plywood. The cost was low and the labor was also low. I figure I could absolutely do this every few years of I had to. I glued 2 pieces of plywood together and the transom is rock solid now. I also decided to keep my boat in my garage so the weather shouldn't get to the transom too much. Just like Wayne, I paid $500 for the boat so spending several hundred for the transom doesn't make sense.

Good information. I used exterior treated plywood when I replaced my transom wood a couple years ago, in my 1971 Terry jon-boat. I had to double layer 23/32" as the original plywood transom was about 1.5" thick. I glued and screwed the layers together, then once dried, applied sealant to the wood before installation. Since the original painted plywood lasted about 45 years, my replacement will be fine until after I'm long gone. -My understanding of marine grade ply is it is more structurally sound, that is has fewer voids (as you stated) and also the exterior has a much better/smooth finish. This because it's use is for hull/deck construction. Marine grade is not generally as good as exterior ply regarding rot/water issues. It requires much more frequent attention to the surfaces (painting, etc) to protect it's integrity. I did use stainless steel marine bolts, washers, and nuts to replace all the aluminum rivets which had to be removed in order to take out the old wood and brace. That was a messy job, as I also used JB weld as a sealer when installing that hardware.

I had some subfloor plywood left over after a house remodel.. soaked it in oil based paint 3 layers and its holding up great

After getting proper fit I seal all the "end grain" edges with a water proof glue or epoxy. I usually apply two coats or as absorption allows. Sand lightly to "fair in" the edges, apply the coating of choice, let dry and refit to attach. I like your video. Thanks.

I replaced the transom on my 1947 aluminum boat about 10 years ago . I used a cutting board material . It has worked well .

I replaced my transom in 2020 and I used marine grade plywood. A 4'x8' sheet at that time cost me $70. since my transom was 1.5" thick, I used that one sheet to make two pieces and glued them together. I then used penetrating epoxy to seal it and did not use fiberglass. The penetrating epoxy is very thin and I thinned it out even more with some acetone. This allowed it to soak deeper into the fibers of the wood to create a better seal. Before the first coat was dry, I applied a second coat of un-thinned penetrating epoxy to add a little more depth to it. All the edges and both sides were coated. I also used this method for the floor of my boat as well as all the hatches. To give an idea of how tough that penetrating epoxy is, I had a few drops get onto a scrap piece of plywood and another piece of scrap was laid on top of it The next day after the epoxy had cured I was cleaning my shop and came across the two pieces that were no stuck together. When I finally managed to pry them apart, the epoxy didn't break. The wood fibers did. Most of the top ply of one piece came off and was still stuck to the other. So is my transom the best it could possibly be? No. If I ever replace it I will replace it with an aluminum transom. It will be expensive, but I will also never replace it.

I just want to say thanks @Wayne The Boat Guy I am also cheap and I managed to snag a 10 ft jon boat in Southern California for $350 by following your advice in a previous video. Now I can replace the transom with your help!

A really great analysis and breakdown of the decision process. One thing you can do with BCX ply is give it two or three coats of slow-setting epoxy using a foam brush. This stuff is relatively inexpensive, goes on like paint, soaks into the wood, and makes the wood waterproof. Any through-holes you drill in the wood--use a silicone caulk (GE Type II) on the fasteners to prevent water intrusion. Thanks again for lunch!

I know someone that used a 2x12 coated with truck bed liner from a can. You could probably coat it with Flexseal as well. So long as you keep the water from getting to it, it should last.

Here is an idea for you. I had a transom replaced on my boat and the marine installer used synthetic decking boards and aluminum plates on both side. Very strong and will not rot.

I'm gust running a old board that I found laying around and it's still good and it has been in there for about 2 years and it is still holding strong.

Good video for options. I replace transoms as a hobby/side job and most people cheap out

I replaced my transom with scrap semi door material. I laminated two sheets together, cut it out and sealed it with resin. we will see how it holds up.

Coosa is like a foam core with fiberglass strands running through it. It is really only strong once it is laminated. The biggest advantages are light weight and water impermeability.

My parents left me a 1985 red-fin 14' fishing boat that I had to cut out of the woods where it's sat for 25 years. The transom was rotted and a home for an ant Colony. I pulled the rotted transom out by hand, no tools.The aluminum was in a great condition. So I went with the Coosa board, cut to fit and installed it. Looks and works amazing, likely to outlast me. Just be sure to wear gloves when cutting. No regrets on cost.

Hi there. I have a 1975 flat bottom Jon boat. Had to Build-up my transom . I used P v c And plywood..Paint both of them in Flex Seal ..👍 As long you paint the wood 🪵 and sell it... I had no leaks . But I paint the outside bottom of the boat in rhino Lining paint... No scratches on the bottom. 5 years so far. 💪🎣🛠

Extremely useful! Thank you. I am probably buying a $500 Alumacraft 1436 today… it has been out in the weather under a deck for a long while.

I made mine out of 2 sheets of ⅛ inch aluminum and a bunch of scraps left over from other jobs. It's good but needs more refinements because it flexes but only about a millimeter of flex. It's coming out and I'm going to be adding stronger custom aluminum bar stock braces. Not bad for having a predator 670 long tail mud motor on it

Oak plywood is a great option also, with Thompsons "wood sealer". But I used the same as you with the Thompsons; green can.

Enjoy the videos. Most cheap guys are one of two types (most of the time): dumb cheap or smart cheap. You are the latter. Nothing wrong with that! I once bought an 18 ft fiberglass boat for $400 with a soft floor . Tore it all out rebuilt the back deck. Used pine 2x4's for the deck anchoring and 3/4 plywood for the floor. Polyurethane everything and caulked any gaps. All in (with boat) was about $1,200 with carpet and some vinyl. Kept it for 5 years and sold out for $800. Net cost was $400/5 years, or $80 per year. Mrs wanted something a bit newer and bigger. Best net $400 I've ever spent on boating.

Good video Wayne.....I have to replace my transom on my 16' alum. I will be using exterior plywood. Good luck.

Another good video. I’m redoing my transom now. I’m doing a plywood transom (that I got for free on Facebook marketplace) and coating mine in fiberglass and going to glass mine into my boat, which is a 12ft fiberglass v hull. My current rear of my boat is about a good kick away from falling apart. So I’m making my transom about 1.5 thick total. Gonna glass a inch thick and then make the last 1/2 inch bolted in.

For mine with just a trolling or a 7.5hp motor I just replaced mine with a 1x6 that I soaked with oil based paint.I do have a HDPE shaped into sort of a V on the outside of the transom,couldn't find a sheet 6-12" w X 40-44" L at the time for the transom on the inside of the boat.Once dry I went back over it with what lower hull paint I had left.Used regular plywood for my rear deck and did it the same way. all done 4? yrs ago,still good,but I do cover the boat over the PA winter.

After giving it another thought. I feel that exterior plywood that have been primed and painted , would be a more cost-effective alternative...Good luck Wayne..

Try the plastic store on Pulaski highway, near Chaps, for coosa, but for that boat, But that should be coated in fiberglass and gel coat or paint.

I don’t see a problem with it but I thought I’d ask. Can I use a 1inch thick piece of aluminum instead of one of these options? I figured I’d be expensive but last for ever

Totally agree with you It dosen't matter to me if it last forever,

I'm looking at a possible transom replacement and I like your idea of BCX plywood . but I will be fiberglassing each layer and then glassing it to the boat hull.

Looking forward to see how it holds up! Good video!

I use hardwood plywood for all my marine applications, it's also slightly stiffer per thickness, than ordinary softwood plywood. Around the same price. Treat it with sealant varnish & it lasts & lasts.

I think that plywood is fine for that boat. For more labor intensive transom repairs might go with better material.

I plan on doing the same thing. Prime exterior plywood and use an oil based paint.

Nice video. I might be the first lab rat to try out starboard or HDPE cutting board material for the transom on a 16’ canoe. It only needs to be 12”W x 15”L x 1”D and is heavy compared to other materials. My small piece will be 3 pounds but that will be okay on this application. Rigidity will be stiff, they seem very durable and from what I’ve seen on another video, screw retainment is fine when bonding two pieces together. I’m a little worried about splitting so I will use washers. I’m cheap too, spending about $50 on the material including some 3M 5200. Lager pieces obviously cost more.

I replace mine with what I thought was exterior grade plywood, when I got home after a 3 hour run I noticed it had al ready started delaminating. It's only 12x12 so I got a 1 inch thick hdpe cutting board and made one up from that. Haven't had a chance to put it in the water yet though.

Thanks for the help! My transom board is 59” long X 16” deep X 1.5” thick. So I can5 get away with a cheaper 4’ piece…darn it. BCX VS ACX is only a $10 difference in Menards. So I might as well spend the extra $10 for a 3.4” 4x8 sheet. I plan on screwing the two halves together to get an 1.5” thickness. I’m just going to use economy liquid nails heavy duty construction adheisive and 1.4” strainless screws to hold the halves together. Then I’ll put 2 coats of fiberglass resin over itand and inside all the holes I have to drill to bolt it in place. I plan on siliconing the bolts as well.

Im about to do one for a 1436 flat bottom. What I was thinking was to use the 1/2" plywood in 2 layers using titebond III and then afterwards brushing on mutiple coats of cheap urethane to seal the plywood

You can apply wood sealer to it and maybe put wood filler or something across the top so water doesn't soak into it. Probably last another 50 years.

Hey Wayne. There is a liquid option you could use, but you would have to make a mold to pour it in. Midwest Fishing channel did a video and the company is called Carbon Core.

5 years ago I used regular old plywood from lowe's on my pontoon floor still strong and never sealed it

Most wouldn't recommend using actual fiberglass to wrap the plywood. Just use the resin. Bondo sells it for less than $20 per pint, and that's enough for the entire transom.

Coosa should be wrapped in fiberglass also. PVC laminated with fiberglass and wrapped, will be much more stiff. Probably not ideal for a transom because a motor puts a lot of twist force on it, but for stringers, should be a good choice.

Great video. I think you're selling your painted BCX solution short. BCX siding with a good paint job and a little regular maintenance easily lasts 20+ years on houses. There's no reason I can think of that it wouldn't last just as long on a transom.

Wayne, What do I got to lose? An expensive motor?😂 Thanks for the videos.

I need to replace the transom, I have bcx plywood 3/4" I can cut the 2 pieces I need. And seal the edges in paint.

I used BC for 1979 grady white weekender and a 1966 mfg transom and stringers. It will last me the rest of my life if it lasted this long so far. Plus I will do a much better job a fiberglassing than they did

I used solid white oak.

Use the cheap plywood and give it a good coat or two of the stuff that they use for pickup bed's to protect them, about the same price ir not much more than painting. A quart should do the trick for the size you have.

I ordered a 3/4" sheet of Marine from "Blue Box" store. special order, took 4-5 weeks to get it.(May 2022) Big mistake,. My particular piece had several visible voids around all edges and it had biscuit/football shaped plugs/patches on the back. I must admit the face was gorgeous/beautiful, but the rest of it was junk, garbage... Paying I forget 150/200$ and that included 2 sheets luan for shipping. sandwiched between Luan. 1st. thing I did was squeegee epoxy on both sides and poured the voids and epoxied all edges. It's a trophy (NOT) It's just laying around as I have not found a use worthy of cutting it up for. I can take BCX or exterior or even regular ply and with time and epoxy or polyester and make it as good as most marine. (if not,,. Better) Furthermore... if you glue 2-3 pieces together making +1" or 2" material who cares if you get a void or 2, just keep the water out of the voids, and if you pour the edges and sleeve any penetrations you should be golden. So right now I am anti-marine grade, I got a raw deal I feel, I may change my mind at a later date. Cheers.

I will be replacing my transom soon and will use starboard or similar hdpe plastic. May be well worth checking out a youtuber named zoffinger. He uses starboard for various projects. It seems very good when used for the right project.

Completely acceptable it will last a good while with a couple good coats of decent paint.

Personally, I would bite the bullet and go with the Coosa. Think of it as paying it forward. In your case, using the BCX, I would paint the heck out of that with a good oil based primer/sealer like Killz.

They do recommend to cover coosa with a layer of fiberglass.. and it doesn't hold screws the best.. For that small aluminum boat 2x4s would be "good enough". Larger boats should do it right, due to the time investment to have to repair it in a year or two

Hey Wayne...did you ever do a video update on the complete transom??

So helpful!

Wayne, are you doing a video on replacing it?,like to see how u did it

I’ve been wondering how some of this composite decking would work if you could get some in wide enough pieces.

Why not use half inch cedar boards glued and screwed together?

I’m sure somebody else has mentioned this, but you should not just bolt Coosa in. It should be laminated for rigidity.

Who is your supplier for Coosa Board? I will need a 1" think and it was close to $600 for a 4x8!

Hi, I was wondering, how is the transom now a days?

How does it hold si ce you made the video? I wanna go cheap too!!

@Wayne The Boat Guy what do you think of solid wood transom? Something like cedar with several coats of spar varnish?

If it was me I would go down to my local auto parts store and pick up a fiberglas repair kit (quart of resin catalyst and some fiberglass cloth in one package). Glue it up and when cured taper the edges slightly run a strip of cloth around the end grain and up the front and rear faces of the plywood, you only need to use a 6” strip of cloth around the edge centered the rest up on the faces of the ply. Yes I know I just added roughly 30.00 to 40.00 dollars of cost but in all likely hood you will never have to do it again and an extra day or so of work to the job will give you a warm fuzzy feeling when the next owner of said craft drives into the sunset dreaming of his water borne adventures swirling around in his mind. (Who knows it might even be me). Their is nothing wrong with saveing money it’s the only way to get the most for what you have to spend on a hobby (if you got enough resin and cloth left do the exposed face of the ply on the outside rear face) The kits if memory serves me where Qt, and I believe gallon size. It’s kind of cheating for me I have a lot of stuff laying around that not every one else will have handy fiberglass cloth some catalyst I need to buy more resin and also have milled and chopped strand reforged fairing materials. Please at least consider tapeing the exposed end grain of your ply it will go a long way to double or triple the life of your transom.

I used exterior 3/4 plywood to refloor my 1969 Starcraft. The original was 5/8 not painted. I put 2 thick coats of Porch and deck enamel. I think it will outlast me

How likely is it these older aluminum boats original paint is lead paint? I just bought one a bit ago that was built in 84 and I know lead paint was banned in 78 so I'm pretty sure mine is fine but it had me wondering. Wouldn't want to dry sand some lead paint in my yard lol

You're talking about a dingy though. I think this wouldn't be advisable with $60,000 boat as the owner would essentially be devaluing his boat and making it unsafe.

I lost a 15 horsepower Yamaha because of that starboard PVCs stall board and work great and was strong until it got wet and no matter how tight you have the mounts it would start slipping and I forgot about it one day and no more Yamaha

Awww! Put some wood glue and bubble gum to patch the holes. Then bleach it all down. It should be good for other 50 years. 😂. Im joking. Thank you for help! I bought my first 12 foot boat. You gave me some great tips.

Bcx plywood 3M 5600 and flex seal

I used regular 1x12 pine boards in my 14’ v bottom. 1971 model boat. The old plywood lasted a long time but was done for in 2018. Ok pine,,, wow, I can hear all the reasoning against it already but wait, I used two thicknesses to fit snugly in the space. I painted all surfaces of the boards with three costs of oil based enamel prior to glueing them together. Not only are they fitted snugly and securely in the transom but they are bolted with SS hardware in every location where there once was rivets and in addition to that I drilled thru the transom hull and boards and used an aluminum skin about 16” long and 10” wide where the motor clamps on on the inside of the boat and its all sandwiched together with the SS number 12 bolts and nuts and washers. Well it’s only been five years since I did that but there’s absolutely no signs of deterioration. No paint chipped off. There’s no flex that I can see even with a 25 hp motor gouging on the throttle all at once. I think this transom will outlast me even if it is pine.

Coosa board. Buy once cry once.

Has anyone considered a hard wood such as oak or hickory? Or is it cost prohibitive ?

Tiny boat nation makes aluminum transom kits. It's all you need. Do it once do it right.

Anyone have thouhts on using hardwood lumber for the transom?

I would just use marine plywood, seal it really well with something like just the resin, and sandwich it with aluminum. Not much money and will last 2 decades at least.

Don’t make a big deal about it where it’s too much and doesn’t get done. Use what you can get when you can. Little jon boats are fun even to paddle or trolling Don’t let it stop you from enjoying the water, especially if the transom doesn’t have a part in buoyancy. Just remember the plug and sunscreen.

I did the same on my little 12foot

You will be just fine if you take your boat out of water after rides. This will help the excessive moisture to evaporate.

Just a thought. It only has to last as long as you do…"

Hi Wayne, any ideas how to attach a plate to my existing transom to lower it about 2 inches, allowing for use of a short shaft electric outboard?

Why not teak or azak

You totally missed deck lumber treated for ground contact. Cheap, pre-stained, will last (much) longer than you or I will. Available in 5/4 stock as well as nominal 1".

With the fiberglass resin I don’t believe you need to use the fiberglass. Looking at other videos where plywood was used for flooring they just used the resin without the fiberglass cloth just to waterproof the wood which is all you would really need to do with the transom.

You can sell plywood with NEW TITEBOND III 1416 GALLON WATERPROOF ULTIMATE WOOD GLUE for dirt cheap $28/gal.

Wow,you really went cheap BCX is a soft wood pine w non water resistant glue vs Marine grade is (hardwood)and water resistant glue. Also people need to pay attention to what kind of marine because there is a non treated which will warp if soaked, vs TREATED marine which you can use immediately without putting anything on it

If it’s submerged, I wouldn’t trust paint.

I would use a board made of cypress!

Cedar wood

Dont you americans have any good oils for wood? Here in Norway we have an oil called Owatrol. My father used this on the transom plate and the floorplates on our boat in the 80s. I own that boat now, and all the plates are the same. The plates we used are the broen coated plywood they use on scafoldings, boats and trailers. If you use this oil every 3-5 years this plywood or whatever its called lasts forever. My boat, my scafolding system, and trailer stays outdoors all year. On my other boat from the 70s, I changed some supportbords under the seats. The old ones wherere made of oak, but I used regular plywood soaked in fiberglass resin. The ends where dipped in resin about 6-7 times, and the rest got 3 layers. 4 years later they are still newish and shiny.

I would change the cheep plywood every 4-5 years if needed.

No need to use anything other than plywood if it lasts over 30+ years. Also, marine grade plywood is no better than treated plywood. As soon as you use epoxy on plywood it soaks in and becomes marine grade plywood lol. Starboard and PVC is not good since epoxy wont bond well to it. It's important to allow your treated plywood to sit around for a few weeks to dry out before you epoxy it.

1" 1/8 + resin so i could let my grandkids have it after im gone

Cypress boards laminate

Don't ever use pressure treated wood on an aluminum. boat. Pressure treated wood contains copper which reacts with the aluminum. Destroys the aluminum.