Aluminum Transom Skin is SHOT! Looking for advice.

[JohnnyMat]

I have an '82 16' Sylvan Sportster that I just picked up and got into. It needed floors and Transom and now a Transom skin. It looks like the milky way (I'll try posting pics).
I'm looking for any advice on the best way to repair. This is the only area on the boat I have found corrosion and holes. I'd hate to have to scrap it but I'm only into it for $400 and it came with a good running Johnson 75 and a nice Sealion bunk...and paperwork.
That said, I'll can the project if need be, however I'd like to know if this repair is worth it. Any advice would be much appreciated. Thank you for your time.

 

[JohnnyMat]

When I bought it the guy said the skin was in good shape with no holes below the waterline. He had sandwiched the old rotted transom between 2 sheets of 3/4" ply and ran allthreads through the transom and through the front section of the spalshwell. Some real engineering! When I scraped the layers of glass/ply/5200 off, not only did water pour out, but I found the mess in the picture.
I was able to salvage a templatable transom but that is the least of my concerns at this point.
Here's a few more pics.
Having troubles with uploading photos. Will try again in a few.

 

[mickyryan]

holy crap it looked like ya got *** end shot with birdshot lol, id repair the holes from inside tape outside put gelcoat on first then layers of fiberglass it should be fixable there is still some left to work with

 

[JohnnyMat]

No Title

 

[JohnnyMat]

No Title

 

[TruckDrivingFool]

It's a tin boat Micky

It's a mess for sure, You could pay someone to tig all the holes closed but I'd look at just skinning it on the outside with another sheet of aluminum, bonded with 5200 and rivets.

 

[jbcurt00]

holy crap it looked like ya got *** end shot with birdshot lol, id repair the holes from inside tape outside put gelcoat on first then layers of fiberglass it should be fixable there is still some left to work with

Its an aluminum boat, this ^^^ repair isnt going to work.

Good luck Johnny, the guys w the tin boats will be along shortly to lend additional advice, but Trucks suggestion of reskinning it is a good one.

To be clear thought, its a mix of corrosion thru holes and holes the PO drilled?

I'd probably tear the boat down to a bare hull and thoroughly inspect every inch of tin and every single rivet (inside and out) before starting any actual work or rebuilding.

ESP if any of those through holes are from corrosion....

 

[lckstckn2smknbrls]

IIRC someone on here fabricated a new transom skin, removed all of the old rivets and riveted it in.

 

[Bondo]

Ayuh,.... I'd scrap the hull, 'n keep the motor, 'n wagon,....

That hull has been patched every which way, but the right ways,....

 

[Tnstratofam]

I would be on the fence on repair versus scrap. Like jbcurt said do the rest of the tear down an do a thorough inspection of the rest of the hull. If you don't find anymore pitting or corrosion then doing a repir like lckstckn2smknbrls sugested is doable. However if there is more damage I would probably lean more towards scrapping that hull as Bondo has suggested.

If you decide to repair it pull the splashwell, kneebrace, and z channel to make inspection of the rest of the stern easier. Then I would try to locate some aluminum sheet to cut out a new skin. I'm not sure what the thickness of the skin should be. Do some research on the forum on what thickness will work.

 

[JohnnyMat]

The rest of the hull is quite solid. I have a few loose rivets on the bow seat brackets but other than that, I haven't found any others. The only area of any other corrosion is where the trim rubrail brackets attach to the boat. I'm not overly concerned about that though. The transom skin has both corrosion and screw holes from PO. I don't believe there is any electrolysis holes, but I'm no expert on that. When I pulled that mess off the transom water was pouring out from between the layers. The P.O. used PT wood and a white sludge had started to form everywhere. But hey....the transom came out in one (technically 3) piece.

What about having a sheet cut and welded to the back right at the rear seam? I would imagine that I don't have to worry about thickness (within reason). I think I can get my hands on a piece of large 1/4" aluminum diamond plate.

What do these boat weigh roughly...if I'm going to go the scrap route? Aluminum is only running around $0.35 out here.

 

[JohnnyMat]

Ayuh,.... I'd scrap the hull, 'n keep the motor, 'n wagon,....

That hull has been patched every which way, but the right ways,....

I don't know enough about these boats to disagree with you, but where do you see other patch work? in the hull? Am i missing something?

 

[JohnnyMat]

Its an aluminum boat, this ^^^ repair isnt going to work.

Good luck Johnny, the guys w the tin boats will be along shortly to lend additional advice, but Trucks suggestion of reskinning it is a good one.

To be clear thought, its a mix of corrosion thru holes and holes the PO drilled?

I'd probably tear the boat down to a bare hull and thoroughly inspect every inch of tin and every single rivet (inside and out) before starting any actual work or rebuilding.

ESP if any of those through holes are from corrosion....

I believe the hull to be in good shape overall. I couldn't find any other corrosion other than where the trim rub rail brackets attach to the boat.
I think the corrosion on the skin is from the PO using PT plywood to sandwich the transom (see pics).

If you look at the "Starry Night" picture of the transom skin, the holes on the outer perimeter of the thin black line are pretty much all screw holes, not corrosion, The corrosion holes are found within that black line.

 

[Bondo]

What about having a sheet cut and welded to the back right at the rear seam? I would imagine that I don't have to worry about thickness (within reason). I think I can get my hands on a piece of large 1/4" aluminum diamond plate.

Ayuh,.... I imagine the original is .063" or .090",.....

Weldin' is gonna be tough, as the P/T plywood has contaminated the aluminum,....
Aluminum has to be PERFECTLY Clean to weld, as in wirebrushed with a ssteel wheel brush to virgin material,....

 

[JohnnyMat]

I have another question. If I get as far as actually replacing the transom...I see they are made in 3 pieces. I can buy 1 1/2" thick Lam beams built with waterproof glue (ACX ply). I was considering buying a 2" x 14" x 8' Lam beam and either biscuit joining or dowel pegging the top curved sections. It would be much cheaper to do it that way, I think just as strong, and as long as I seal it properly...should be just as water tight. Any thoughts?

I've already priced out ACX, Marine, and MDO board. I'm just looking at a cost and time prohibitive alternative.

What kind of budget should I set on repair/replacement costs of that skin to make it worth it. Spend no more than $ XXX to fix?

 

[JohnnyMat]

Ayuh,.... I imagine the original is .063" or .090",.....

Weldin' is gonna be tough, as the P/T plywood has contaminated the aluminum,....
Aluminum has to be PERFECTLY Clean to weld, as in wirebrushed with a ssteel wheel brush to virgin material,....

Its .090"

 

[Tnstratofam]

Most of us who have done a similar transom have used one piece transoms in place of the three pieces Starcraft originally used. A good exterior grade or marine grade plywood sealed with epoxy, or Old Timers Formula, or Spar varnish will work good.

As to how much is to much to spend that will be dictated by how much you like that particular boat over others that may be in better condition and how many are available in your area.

 

[JohnnyMat]

Most of us who have done a similar transom have used one piece transoms in place of the three pieces Starcraft originally used. A good exterior grade or marine grade plywood sealed with epoxy, or Old Timers Formula, or Spar varnish will work good.

As to how much is to much to spend that will be dictated by how much you like that particular boat over others that may be in better condition and how many are available in your area.

I really do like this style of boat. I think its great for a family cruiser and a fishing boat. Its also a good size and weight to tow around. That said, I have no "emotional attachment" to this particular boat so I'm not afraid to go either direction with it. I've called about the 2 following boats today which I found on CL and am waiting for a return call. There's not much in the way of similar Aluminum boats in my area that are within my price range so either way I'm doing some kind of work.

http://philadelphia.craigslist.org/boa/5644943827.html
http://cnj.craigslist.org/boa/5558378108.html
http://cnj.craigslist.org/boa/5662835045.html

At least give me a few days before anyone sweeps these from under my feet!

 

[Tnstratofam]

The first one you linked looks like it may have similar issues as the one you're working on. The middle one could be a quicker redo, and the last one is hard to tell what potential problems it may have from the side view.

 

[JohnnyMat]

I found an '85 18' Smoker Craft in CT. It's the exact same layout as mine and the guy is willing to sell without the small kicker motor and trailer. He blew the 70HP Johnson last season. He had the floors done 3 years ago and the interior is only 2 years old.
The only issue is he didn't even know these boats have a wooden transom in them. He thought it was all aluminum. He sending me pics from under the splashwell. He might be in for a surprise himself! Either way it's a nice boat and he sounds eager to sell it. I'll see what happens.