Aluminum Boat Transom Repair

[Packerjim]

Hi, I am new to iboats, but this looks like a great community and I am hoping I could get some assistance. I was given a 12? aluminum boat, and would like to use it to take my kids fishing. The problem, as you can see in the pics, is the wood on the back of the transom is rotted, and the boat leaks (no surprise). I have been reading in the forum here, and I think I know how to replace it, but am hoping for some clarification.

I plan to replace the wood with marine grade plywood. There is an aluminum transom, so the wood, I believe, is for added strength. I do not plan to reuse or replace the green vinyl, or whatever it is, cover that you can see folding over. From what I have read, I then need to coat with epoxy and paint it for UV protection, and replace the hardware with stainless steel, coated with a sealant. Am I close, or is there another way to go?

The depth of the ?pocket? that the wood would fit in on the back of the boat is 7/8 inch. Should I use 3/4 or 1 inch plywood, which would stick out a little?

Do I need to seal the seam between the edge of the wood and the boat, or concentrate on the seams inside the boat? If so, what kind of sealant should I use?

Thank you for any feedback you can provide.

 

[jigngrub]

Re: Aluminum Boat Transom Repair

Can we see some pics of the inside of the boat at the transom?

I've never seen a tinny with the transom wood on the outside covered with whatever that is that is covering it.

As for the seam sealing, you should use Gluvit or Coat-it on the inside of the boat on the seams. Both of these are epoxy mixes as well and will need to be painted over for UV protection.

As for the plywood, recheck the dimension after you remove the rotten wood. More than likely the wood was 3/4" plywood and has swollen due to water absorbtion.

 

[jasoutside]

Re: Aluminum Boat Transom Repair

Wow, this is a new and different challenge!

Yah, like grub mentioned, a shot of what ya got on the inside would be really helpful.

Welcome to iboats

 

[Pmccraney]

Re: Aluminum Boat Transom Repair

Holy backwards transom, batman...

Yeah, what they said^^^^ not used to seeing the wood on the outside of the boat . However, with a little elbow grease and creativity, I am sure we can get you back on the water...

 

[kfa4303]

Re: Aluminum Boat Transom Repair

+1. That is a funky set up. Thankfully, repairing/replacing a transom is a pretty simple job on an aluminum boat (aka "tin boat"). You'll need to start by removing all of the hardware holding the old transom in place. Don't be surprised if you have to hack, chop, scrape and drill the old bolts and rivets out. Once all of the old material is removed, thoroughly clean the raw aluminum with a some scotch brite and a bit of acetone. That should leave you with a nice, clean surface to work with. You'll then want to make a template for the new transom out of cardboard, or by using the old transom itself. Assuming it came out in one piece. Once you have the dimensions, you'll want to transfer the pattern to 2 pieces, 3/4" NON-PRESSURE TREATED exterior grade plywood and laminate them together using construction adhesive. Once the 2 layers have fully bonded you can dry fit the transom into the boat. If all is well, you can now pre-drill the holes for the mounting hardware. After the holes are drilled, you'll now want to seal the wood. There are a variety of methods including spreadable 2-part epoxies and/or fiberglass mat & resin, but for your purposes I would keep it simple and use 3-4 coats of SPAR URETHANE, which you should be able to get at any hardware store. After all of the layers of sealant cure, you can now install the transom using STAINLESS STEEL hardware (bolts and fender washers) dipped in 3M 5200 marine caulk/adhesive. That's all there is to it. You can paint the transom, if you like, but the Spar Urethane is UV proof, so there's no need to do so. Good luck. Keep us posted.

 

[Packerjim]

Re: Aluminum Boat Transom Repair

Thank you for the feedback and warm welcome everyone. I will get some pics uploaded of the inside of the boat. I will also remeasure the depth of the pocket that the wood will fit in. Fortunately, the green vinyl cover should come off in one piece, which I should be able to use as a template.

 

[Georgesalmon]

Re: Aluminum Boat Transom Repair

From the picture it looks like the transom aluminum part is actually sheared off of the angled part that fits inside and is riveted on. If thats the case you have bigger problems than the wood. I can see the edge of the lip that is riveted to the hull. The transom is a one piece stamped piece that had a lip that goes onto the hull where it is riveted with a piece of seam sealing tape between the hull and the transom. I hate to say it but I think you need a whole new aluminum transom or some very creative welding that cannot be done while the transom is on the boat. The rivets will need to be drilled out and then the welding done because welding in place will destroy the seam sealing tape. Looks like the metal is sheared off on the port side too. Need more pictures of the outside, some close ups of the edge where the transom is attached to the hull. IMHO, I would not buy any wood yet. What brand of boat is this?

 

[Packerjim]

Re: Aluminum Boat Transom Repair

I have posted a picture of the inside of the boat, below. Sorry for the delay in getting this uploaded, and thanks again for all the suggestions.

As you can see, there is an aluminum transom. I think the exterior wood is mainly for strength, but I am no expert. The large piece of aluminum where the motor sits was a repair I had done this spring. There was a crack on the top edge of the boat. I had it welded and they made this "bracket", which is really quite strong and well constructed.

If I do need to reseal the inside edge, that bottom plate is going to be problematic as it is riveted in place.

If this project becomes more hassle and expense, I may just look for a new boat. The trailer and motor are great. I've done some looking, and it doesn't appear many people sell just the boat w/o a trailer or motor.

Thanks again everyone!

 

[jasoutside]

Re: Aluminum Boat Transom Repair

Wow, I am so confused right now! So yah, your transom wood is on the outside??

Oh man, I think I'll come back in the morning and look at it again. Maybe it'll move to the inside of the boat while I'm sleeping:redface:

 

[Bob_VT]

Re: Aluminum Boat Transom Repair

Holy modification Batman!!!!

Based on the pop rivets I see ......... there are multiple modifications there. It is salvageable but I see some work in your future. I would remove that large plate and take more pictures. The wood belongs inside the transom and someone made an interesting modification.

I would install wood back inside and leave the exterior w/o wood and only aluminum..... maybe a piece of 3/8" plywood outside to mount the motor against.

Yes, my opinion is remove the large plate (which would require cutting some welds I see .....take pictures and we will guide you from there.

 

[kfa4303]

Re: Aluminum Boat Transom Repair

+1. It's an inside out transom! The wood "should" be on the inside with an aluminum skin out the outside using stainless steel hardware to mount it all in place. It's salvageable, but do have some work ahead of you. You'll have to decide if it's worth the time and expense. Keep us posted.

 

[jasoutside]

Re: Aluminum Boat Transom Repair

Ok, well, it's been like a full day of me stewing on it and yup, that transom is still on the outside.

Not a biggie, she's totally fixable!

Yah, I'm with Bob and KFA there. I'd pull the wood off, take that upper plate off (leave the lower one though), pull the bolts n' stuff off, and then post up some photos.

I can't help but think that somebody decided it was a good idea to put the transom wood on the outside (full size) and cover it with that vinyl.

Factory?? Uh, man, maybe. That would just be strange if it was though.

Cheers

 

[oldsub86]

Re: Aluminum Boat Transom Repair

We had a similar boat at one time. Ours had a smaller plywood part on the outside and a plywood part on the inside as well.