here goes nothing...i'm gonna try replacing the back of my starcraft

[sublimebass]

i'm gonna try it and see i went to two shops they told me it was junk and another said 1000-1500$ just to fix the bottom that's not dealing with the corrosion on the transom...i think not..so i'm going to take all the rivets out(what's the best way??)then take the old piece into a fab. shop and get them to make me a new one then..rivets it back on(where does one get the rivets and a seal..in canada)..i'll try and post some pic's...

 

[sublimebass]

Re: here goes nothing...i'm gonna try replacing the back of my starcraft

isn't that always the case...you convince yourself your gonna do something then you see a post that changes your mind.i seen a boat worst off then mine..1 last fab shop says they can weld a new peice over the back of the transom alum. then under the hull at the back to patch a hole..now will that weaken the alum. thats there..it's very corr. i want to gulvit the old alum. first..but i'll have to get the corr. out of the pits ...is there a easy way..i'm using easy-off and a wire brush...when i put the new transom wood in i'm suppost to epoxy it?? thats just the epoxy without the hardner right??i got the last can of gluvit in alberta i think... how much do i need??? for a 16ft starcraft?

 

[Bob_VT]

Re: here goes nothing...i'm gonna try replacing the back of my starcraft

PLEASE do not detach the transom until you post more photo's. A 16 footer even with a bad transom is repairable.

Where is the corrosion? I imagine that the transom is fairly sound and strong near the rivets...... do not break that bond.

Gluvit goes a long way since it is not absorbed by the aluminum.

My suggestion is a possible sheet of aluminum to cover 99% of the transom mounted with a layer of gluvit and attached with closed end rivets.

 

[sublimebass]

Re: here goes nothing...i'm gonna try replacing the back of my starcraft

heres my only problem...i wanted to just rivet a piece to the back but the bottom is worn right out.under where the transom brace is riveted to the hull about a 1in hole and rotten to fix the hole the new ppiece has to wrap around the rivited joint right on the bottom i don.t think rivets would hold a good seal around from the hull to the transom...the transom alum. is pitted badly all across where the transom wood was.of course the whole transom and bottom are spotless now...it was so badly corrodid under the transom brace i have to get a new one made i can break pieces off the brace...oh ya i found a aa bat. under the brace rotten

 

[sublimebass]

Re: here goes nothing...i'm gonna try replacing the back of my starcraft

 

[reelfishin]

Re: here goes nothing...i'm gonna try replacing the back of my starcraft

There are several things to consider with this type of repair, the first is that there is a sealer in between that multi-riveted seam around the transom, second, is that you will most likely not be able to duplicate that original bond working by hand.
With the hole being so close to the edge, your concern will be in how much damage a repair will do to the rivet seam.
If it were mine, I'd probably opt for a welded patch over that area, then once the support is reattached and the hole patched, then deal with any possible heat damage to the seam with a few good heavy coats of gluvit and several coats of paint to protect the repair.

If the hole didn't involve an inner brace and the proximity of the rivet seam, I'd consider an epoxy repair but that inner knee brace is what tranfers engine torque to the hull and supports the transom, so any repair there must be pretty durable.

Once the repair is made and proven watertight, you could then make the outer transom more cosmetically correct with some marine filler and paint if you so choose.

 

[Gnarly]

Re: here goes nothing...i'm gonna try replacing the back of my starcraft

I would definetly rivet a doubler with gluvit or proseal 870 between the sheets with closed 5052 aluminum mandrel rivets rather than try to match the countours of a replacement transom sheet, It could be done by using a plywood form the same way most homebuilders build aircraft wing ribs and shrink the corners with pliers or a shrinker stretcher. I'd go right over it after I was sure I had the corrosion stopped with some vinegar/water and a brush followed up with some zinc chromate.

 

[sschefer]

Re: here goes nothing...i'm gonna try replacing the back of my starcraft

One of the biggest warnings I ever got was after I told a pro boat builder that I was going to remove my transom skin. His warning was stout and made a lot of sense. The whole boat is under tension, that's what gives it it's strength. Removing the transom skin is like removing a keystone everything depends on it to stay in alignment.

If there is no way to fix the current problems with Marine-Tex, you need to apply a new layer of skin to the transom. The problem is that it will be hard to keep sealed and will eventually trap water. Welding is not an option because the original aluminum is hardend and will crack unless done under very controlled circumstances (expensive).

My recommendation is to cosmetically patch and fill with Marine-Tex, sand smooth with 80 grit paper and apply a generous coat of thoroughly mixed Gluvit to the inside.

Then, replace the transom board with 2 layers of Super Ply or Marine Ply and a Carbon Fiber layer in between. Laminate it using the correct resin and you'll have a super strong transom to bolt you knee braces to.

If needed you can make a plate to cover the area where the engine mounts and the knee braces bolt through. Use 3M 5200 to seal it to the transom and then use Truss Head machine screws to pull it tight and flush.

 

[joblo33]

Re: here goes nothing...i'm gonna try replacing the back of my starcraft

I've rebuilt two aluminium transoms that looked as bad or worse than that. Both times I just sandwiched the transom with thick sheets of aluminium with zinc chromate and sealant between the layers before attaching them. I was pretty overkill with the Starcraft Offshore transom, but that's because I mounted twins on it. Here are some pics of what I did.

Aroliner Debonaire:

Starcraft Offshore: