Transom replacement

[rebars1]

I'm retoring a 1959 14' Wizard runabout with a 35hp Johnson. I've removed the old rotted transom from the inside, leaving the outer skin. The old transom was 3/4" plywood full depth with the upper 8" (from the splashwell up) doubled up. The glass on the inside (under the splashwell) only came up about 10" on the inside face of the wood. I want to install a full double layer 3/4"plywood transom. Questions: 1)what glass should I use between the plywood and outer skin or the boat? 2)What glass should I use to sandwich the two layers of plywood together, and do I screw them together also? 3)I've kept 1" fin of the original glass at the inside bottom of the transom to form a slot for one layer plywood. What glass should I use to attach the bottom of the boat to the new tramson?<br /><br />Sorry for all the questions, but this is my first boat restoration project. Thank you.

 

[jheron]

Re: Transom replacement

Well I am no expert by any means as I am also on my first boat restoration but I will tell ya what my research led me to... I am going to use 6oz cloth and sytem3 epoxy inbetween transome and stearn I will apply the cloth with unthickend epoxy and fill the weave with thickend epoxy using cabosil as the thixotropic agent. I have read mixed opinions about the use of cloth inbetween the 2 layers of ply so I think just to be safe I will use the 6oz cloth and thickened epoxy to glue the 2 pieces (or 4 in my case ) together.<br /> For the final glass I was told to use one layer of 6oz then a layer of 24oz roving with a final layer of 6 oz to finish it off. Now I went and purchased this stuff and I can tell ya that the 24oz roving looks like its going to be a real treat to wet out!! Not sure if I realy need that heavy a cloth or not but thats what I have hope that helps ya a bit!<br />Regards Jon

 

[petrolhead]

Re: Transom replacement

No point using glasscloth between 2 layers of 3/4" ply, it won't achieve anything, just glue with epoxy. Due to the size of the panels you'll probably need to use screws to clamp them, at least in the middle. Drill clearance holes in one sheet and use self tapping screws through the holes and into the other sheet. You have two options here, use expensive S/S screws and leave them in, or use cheap steel screws and take them out and fill the holes. The screws won't really add any strength if you leave them in though.<br />Bond the new transom in with thickened epoxy resin, and use woven glass tape and epoxy on the inside corners. You don't need to cover the inside with glasscloth, just a couple of coats of resin then paint if you're painting the inside of the boat.

 

[jheron]

Re: Transom replacement

Well thanks again petrolhead So you dont think it will add much for strength to use the 24oz roving over the transome? Just tab in the edges? with the 24oz roving? Is there anything I should coat my screws with to make them come out easeyer? If they dont add any strenght I would just as soon take them out to avoid any future mounting problems?<br />thanks Jon

 

[petrolhead]

Re: Transom replacement

Glass may add significant strength to thinner ply, but not as much weight for weight as just using thicker ply! It's most useful to give a hard dent resistant waterproof surface for plywood.<br />You shouldn't need to coat your screws with anything, just take them out before the epoxy is fully cured, once the resin starts to gel give it another 10-15 minutes then remove the screws.<br />If one does get stuck heat the head with a large soldering iron, that will soften the glue and allow it to come out easily.

 

[rebars1]

Re: Transom replacement

You guys are great! Good information. <br /><br />How rough do I need to make the inside surface of the boat skin to adhere to the epoxy/plywood transom? <br /><br />Is it better to laminate the two layers of transom plywood first, or progressively lay them up in-place?

 

[emckelvy]

Re: Transom replacement

Check out the Seacast method of repairing transoms:<br /><br /> http://www.transomrepair.com/

 

[rebars1]

Re: Transom replacement

EdMc: Thanks for the tip. I had considered using that product until I removed the splash well and found that the inner layer of glass against te transom only came up a few inches onto the plywood. With Seacast, it looks like you need to have full height glass both faces to create the form to pour the material into.

 

[petrolhead]

Re: Transom replacement

How rough do I need to make the inside surface of the boat skin to adhere to the epoxy/plywood transom?

The rougher the better really, but cleanliness is more important, make sure it's as clean as possible and thoroughly degreased with acetone (wear gloves!).<br /><br />

Is it better to laminate the two layers of transom plywood first, or progressively lay them up in-place?

Whatever's easier for you, it shouldn't make much difference.<br /><br />For both gluing in the new transom and laminating the two pieces you'll need to thicken the resin with colloidal silica. When you glue it in use plenty of thickened resin to make sure you get no voids, any excess that oozes out can be scraped off and spread around the inside so it won't be wasted.<br />I'd suggest priming the wood before gluing too, mix a batch of resin (slow hardener to give yourself time, and mix in a wide mouth container) and brush some over the wood before you thicken it so that it soaks well in, then thicken the remainder and use this as your glue. You'll want it about the consistency of mayonnaise, so that it no longer runs and a large blob will support itself.

 

[qaztwo]

Re: Transom replacement

Hey jheron a little off topic, but I also used 24oz cloth and mat for my stringers and transom. The best way I found to do it was to place the piece of cloth on a piece of plastic, I used some sheets of plastic that painters use to protect floors with, place the fiberglass on the plastic. If you want to do 2,3 or any amount go ahead and place them on top of each other, then I applied the epoxy to the middle of the cloth and worked out. Then I covered the top with more plastic and used a razor to cut the plastic to the same shap of the cloth. Then simply wet the wood and peel of little by little of the plastic and and continue to lay down the cloth. Once all down go back with your brush or squeegee and on the side that still has the plastic on it work the cloth down. You can actually see the air bubbles being forced out. When finished peel off the other piece of plastic and go back through and brush down any ends that might of ben pulled up. Sounds like a lot of work, but only took me about 20 minutes to do a stringer.

 

[G DANE]

Re: Transom replacement

Smart trick - I will definately try that - I did a couple of small repairs, using wax paper or baking paper.

 

[jheron]

Re: Transom replacement

Ya thanks for the tip I will try that also I was also using wax paper for forming up a hole in the back of the boat.<br />Jon

 

[rmacdonald]

Re: Transom replacement

Slightly off topic. Thought Id keep this discussion in particular within the transom subject. <br /><br />Im new to boat repair and have kept a keen eye on the discussions on iboat in an attempt to gain a better understanding of the process when replacing a transom. The candidate is a small powerboat that needs replacement stringers, deck and transom.<br /><br />Q: Is it absolutely necessary to remove the top half of the shell from the hull to gain access to replace the transom? I wouldnt want to go to the extreme if its not entirely necessary.

 

[jheron]

Re: Transom replacement

It all depends on your boat with my boat the work involved in seperating it was way to much so I cut out the splash well and made a 4 piece transome <br />Jon

 

[qaztwo]

Re: Transom replacement

Hey Ronald I have a i/o, and I did not remove the outer shelf or top. That being said it was a very and I do mean very tight squeeze to get the new transom back in place. Also I had to make some clamps up using 2x4's and thread rod. I have some more pics to upload to my site. There is a link to it in a past post of mine called it has began