just rebuilt transom question

[slvrwolf1]

I just put a new transom on my 1973 ensign and I was told 2 pieces of 3/4 plywood but mine would only take a 3/4 piece and a 1/4 piece is that going to be ok. also I was ready to epoxy these together and I was told I needed to put fiber mat in between the 2 and not epoxy them together. will it work if I dont fiber mat in between the 2 plywoods. I was able to pick up the entire back of the boat off of the trailer by pushing on transom so it seems strong.

 

[sdunt]

Re: just rebuilt transom question

Well, W/o pictures we're kind of at a loss. Generally yes, transoms are 1 1/2 thick. Now if this a 10 ft jon boat with a 9.9 hp outboard, then 1 1/2 inches for the transom is a little much.

What was in the boat originally?

As for laminating the two layers of plywood, the statement about mat is correct because there are just enough flaws and imperfections in the wood that you'll never get the two pieces to fit together tightly. You need a filler in your epoxy glue. You can thicken the epoxy or use a fiberglass reinforcement. PS. Off the shelf mat is not compatible with Epoxy. It has a glue in it that holds the fibers together and the mat flat. This glue will only dissolve in Styrene, the solvent in Polyester resin.

There are specialty 'epoxy mats" look at the last item on this page: http://www.uscomposites.com/mat.html

Fiberglass clothe and epoxy are no problem and you can use clothe instead of the mat to laminate the two layers of wood together.

I applaud your tests by pushing on the transom, but can you develop as much horse power as your OB does and what about the force your 250 LBS brother in law on the end of the ski tow rope puts on the transom?

 

[slvrwolf1]

Re: just rebuilt transom question

thanks for your reply. this is my first transom so I have no idea about what I am doing it seems like the hard part was getting the old wood out. I have no pics taken of the transom but the boat is the one in the avatr pic. it is a 73 ensign 16 foot with a 75 hp evinrude. Thanks to you I understand why the fiberglass needs to be in between. No one explained it to me like that. I measured the cap and it was about 1 1/14 but the 1 inch I have in there is a real tight fit. I got the boat, motor, and trailer for $400 so I figured I can put some money and time into it and still be ahead. I keep just looking forward to all the fun I will have when it is finished. my first boat was a aluminum v bottom 13 foot with a 1956 10 hp and I had fun with that, but that just got me wanting more of a boat lol. thanks for the help

 

[slvrwolf1]

Re: just rebuilt transom question

I got home yesterday and went and got the fiberglass mat and some cloth and started with the fiberglassing. First time I have done that before too but it wasnt bad. I think after a few times I may be able to do it and make it look real good. I may take the boat out this evening and go easy on it just to see how it reacts. If I have to make it stronger than the 1" I was wandering if I put an alluminum plate in there if that would work?

 

[sdunt]

Re: just rebuilt transom question

If I have to make it stronger than the 1" I was wandering if I put an alluminum plate in there if that would work?

Need to get us some pictures. You can 'blog' your project for FREE at www.shareaproject.com and its also a great way to store pictures to link with forum posts.

Keep in mind that the job of the transom is to transfer the force of the outboard to the rest of the boat, via the stringers,the floor and the hull. Putting a metal plate in the center of the transom does not accomplish this task. So you either need knee braces http://www.shareaproject.com/pages/imageDetail,p,148,i,3028,00.html

Or to increase the thickness of the transom all the way across the boat. Some people have tried to patch transoms with stainless plates, etc. I think some of these are even available commercially, but those also go all the way across the boat again to transfer the loads.

If you absolutely must, and this can get ugly, you can reinforce the transom on the outside. The typical redneck way to do that is to just screw another layer of plywood on to the outside of the fiberglass.

If necessary you can do it right and make it look decent, by glassing over the reinforcement and blending it into the boat.