Transom rebuild

So I am finally attacking this rotten transom seen in the pic below. This is off of my 1965 14' semi V. I have a couple of questions centered on beefing this transom up. Right now it is at 1 inch. I mistakenly thought it was a 2 incher when I went to Lowes to pick up a board. The 2 inch board will of course not fit in the lip of the transom frame. I thought what the heck,...If I get a bigger motor later, it might give me more support if I mount the thicker board.

1. Do you guys see any issues with flattening this lip out to allow the 2 inch board? I will also have to flatten out what seems to be a thick aluminum or steel plate bracket.

2. Will the thicker board cause any out of the ordinary pressure on the lower half of the transom that is not supported by a board?

When I replaced my transom I made it the same as the factory 1" thick . I then added an oak 1"x6"x48" glued and screwed together. I run a 25hp motor on my 14x36 jon.

Did you get plywood or a solid board? The ideal is to use plywood. My transom is 2 3/4 inch sheets glued together to get to 1 1/2 inch thick transom.

I did see one flattened out to accept a 2x12 - not sure how well it worked though. Seems like a solid board would flex a lot more than plywood.

Also, as to your motor, you probably don't want to exceed the manufactur's max hp rating. It can be bad for your health

"Also, as to your motor, you probably don't want to exceed the manufactur's max hp rating. It can be bad for your health"

Also could be real bad for your wallet if anything bad were to happen....insurance would deny any claims....if you could even get insurance....

you'll be fine. I just did the same to mine but i also add'd a L bracket on each side twards the bottom to help tie the board to the sides of the boat

You should be fine. I have seen both plywood and 2x's used. Both work just fine.

I may decide to go back to Lowes and get another board that fits the factory settings and then add an extra board on top for support.


wasilvers, back to your comment about a solid board....I don't really know a lot about wood (plywood vs. solid board)...Thx for the info....My instincts tell me that a thinner plyboard would flex more than solid board? Why would solid board flex more?

Loggerhead Mike, do you happen to have a picture of your transom with the L Brackets? And I am assuming you used solid board instead of ply...If so, what thickness?

Thanks for the info. guys...much appreciated!

As an avid woodworker, I can tell you with great confidence that the ply would out last the solid wood. Wood expands and contracts with the temperature. Solid wood's grain runs all in one direction, meaning the wood is apt to shift and twist. With ply, they run each ply's grain in a different direction. This makes it stable and less apt to twist, bow, bend, and though it may not seem it, Stronger. Just laminate two pieces of quality grade ply together, and wala. Most home centers offer cutoff's at a bargain price. If you can, use some ply that has at least 9 ply's to it.

I did my transom out of 2 layers of 1/2" plywood. I bought a 2'x8' piece that was damaged.

Loggerhead Mike, do you happen to have a picture of your transom with the L Brackets? And I am assuming you used solid board instead of ply...If so, what thickness?

Click to expand...

I can have them this weekend for ya. Im still waiting on my welding supply's to get here to fix acouple cracks in the transom and to weld the braces on. Stuff should be at the house today or tomarrow, i hope.

yes i used solid pine 1" thick for both boards. they are saw mill cut so nothing to pretty but they're solid as a rock rite now. I know you shouldnt use a soft wood but the boards have been sitting in our barn for years so i said what the heck its free, it will still be over a year or 2 if they do get soft on me. If my stuff gets here today ill have pics for ya tomarrow

The hardness of a species of wood is NOT determined by soft woods or hard woods. Though this is often beleived by about 90% of the population. Hard woods and soft woods differ from one another by the type of seeds that it produces. Hardwood trees produce seeds with cover, like walnut trees produce seeds inside of a shell. Softwoods produce naked seeds like conifers.Look it up if you want. And as far as pine goes... the longer it sits and dries, the harder that stuff gets. Problem is it is not a stable wood, and is very pron to warping. As far as it lasting a couple years of service, it will with proper coatings of protection.

I can not tell you how many transom's I have replaced. I do it for a living. The ply wood you have will work fine. You can get the smaller one and it will be fine also. You could also use a 2X board and that also would work. Plywood is by far stronger. A piece of plywood with fiberglass wrapped around it would make it last a long time and make it very strong.

OK I think you guys sold me on plywood. I am going to go buy a piece from Lowes. Is there a recommended wood type of plywood that I should get? I don't want to have to replace this transom for a long time. I had also planned on coating it with Thompson water seal and then deck stain. Do you think this is OK or should I find some fibergalss coating and if so what kind should I get at Lowes? Thanks to everyone for educating me on this. I knew nothing of this before.

Unless your confident in your skills, I'd just stick to the thompsons. I do fiberglass daily and it would last a long time. But it is expensive unless you can get it on large quantities. The amount that you would probably be able to buy at the local hardware/automotive store would be very expensive. Then you would have to buy the hardner and the mat. If you were inclined to do that I could walk you through it. In that case I would buy treated plywood, and since your putting a layer of fiberglass over it it will not react or corrode the aluminum.

Otherwise I would just get a piece of plywood NOT TREATED and apply the thompson's water seal.

The hardness of a species of wood is NOT determined by soft woods or hard woods. Though this is often beleived by about 90% of the population. Hard woods and soft woods differ from one another by the type of seeds that it produces. Hardwood trees produce seeds with cover, like walnut trees produce seeds inside of a shell. Softwoods produce naked seeds like conifers.Look it up if you want. And as far as pine goes... the longer it sits and dries, the harder that stuff gets. Problem is it is not a stable wood, and is very pron to warping. As far as it lasting a couple years of service, it will with proper coatings of protection.

Click to expand...

thanks brother!

If you get some ply scrap's at the local home center, look for any dense ply, don't matter what species. Although usually oak, and mohagany are pretty darn good ply's. I usually won't even buy plywood unless it has at least 9 ply's.when you use the plywood method, and don't use fiberglass, its a good idea to also use a waterproof outdoor use wood glue to seal up all edges. Just goop a bead on and use your finger to smear it good all over, let it tack up a lil and wipe off excess with a rag. Then thompson's it.

I dropped by Lowes today to look for a piece of ply that was 1 in. thick and could not find one. I guess this is the reason why some of you took two pieces and glued them together.

1. What kind of glue did you use to glue them together?

2. Did you glue them and then cut both at the same time to fit your transom?

3. Also, I am assuming that I am basically going to have to buy 2 big (whole) sheets of 1/2 in. ply unless Lowes has some cutoff available...correct?

Thanks guys,

I used Gorilla glue but Tite bond III will work. My transom started out as 2 pieces of 1/2" plywood 12"x48". I glued them together then cut to the final shape. Then I added the 1"x6"x48" oak board glued and screwed to the plywood.

Man your transom must be huge? I would think you could get away with one piece of 1/2" ply, cut in half and glued together. Either way, when you go to glue the two pieces together use a cheap paint brush and goop on the glue, then brush it around so that you have an even coat of glue on both surfaces to be stuck together. As far as what brand glue, I would go with the Titebond lll, Gorilla glue is good but unless they changed something ( maybe, have not even looked at that stuff in over 2 years) their glue is not for outdooor use. Titebond lll should be green and say for outdoor use. I did our patio set a couple of years ago and did two of the chairs with gorilla glue cuz I was out of titebond. Those chairs eventually needed to be torn down and reglued. I believe that titebond is less expensive also. But just check, I'm sure Gorilla glue has something now that is for outdoor use. Good luck and keep us posted.

So I went to Lowes and purchased some Oak Boards and am working to replace the transom. It is harder than I thought to cut based on the template. I have a curvature in my transom that was harder to cut than I thought. My Question is, "I have some left over wood and my current wood piece for the transom only extends alittle over half way down the back end aluminum piece of transom. Is there any value in adding a second piece of wood (connected to the main transom piece) which will allow a full coverage of the back end with wood? You may see what I am talking about by looking at the first picture.