Transom Replacement Question

[trailblazer2]

The 1"x8" board in the transom of my 15' Lowe boat (1982 model) rotted out. I removed the rotted board and the cover on one side of the foam floatation to figure a way to install a new board. I read several threads on this and it appeared that the "remove the bottom bracket, drop the old board out, install the new one...." would work. NOT SO! no way to get a solid new board in without removing all the flotation foam on both sides to remove the lower angle bracket OR cut off the corner cap braces and cut the back plate of the transom off and re-weld it all back together. Also have to remove the amgled support brace that is attached to the bottom and the lower halv of the transom.

Question: Is it critical the baord extends to the outer edges of the boat sides for strength and lateral structural support? Or, can I slde in a "short board"? Alternatively, can I slide 2 pieces in that are cut in the middle, but extend to the edges? neither sounds like a good idea.

Anybody got any ideas?

 

[ezmobee]

Re: Transom Replacement Question

I think we're going to need some pictures.

 

[oops!]

Re: Transom Replacement Question

yep....we need pics......and its nothing to remove the foam.......the knees will have to come out

 

[trailblazer2]

Re: Transom Replacement Question

After researching foam, I concluded that is not a significant issue.... can be easily replaced at not too much expense.. have ordered some.... any tips/special precautions on application? Should I cut out only the amount necessary to remove the angle brace (not talking about the knee brace) or just knock it all out and put in all new? That is, will the new foam "seal" with the cut face of the original foam?

I need advice on how to drill holes in new board to get the new holes to line up with the existing holes in the back plate and angle braces... I'm thinking I will probably need to fill the old holes and drill all new ones next to the old ones... any suggestions??

Attached are 3 pics to show what I am dealing with

 

[ezmobee]

Re: Transom Replacement Question

Man what a terrible design. I can see the mess you're dealing with. I really wish I had a good suggestion on how to get the new wood in there.

As for the foam, I'd ditch all the old stuff and replace it with layered cut sheets of the pink or blue sheet foam from Lowe's/Home Depot. It does not absorb water unlike the old expanding stuff can.

 

[trailblazer2]

Re: Transom Replacement Question

Man what a terrible design. I can see the mess you're dealing with. I really wish I had a good suggestion on how to get the new wood in there.

As for the foam, I'd ditch all the old stuff and replace it with layered cut sheets of the pink or blue sheet foam from Lowe's/Home Depot. It does not absorb water unlike the old expanding stuff can.

So, you are saying the 2#/gal pourable closed cell foam is "not good" to use?

 

[jasoutside]

Re: Transom Replacement Question

Wow, looks like they started with a board and wrapped an aluminum boat transom skin around it. What a pain. I wish I were standing there next to you to see the big picture on how to get good wood back it there.

From where I'm sitting...

removing all the flotation foam on both sides to remove the lower angle bracket

that might be as good as it gets. Sorry I can't be more helpful.

 

[jasoutside]

Re: Transom Replacement Question

So, you are saying the 2#/gal pourable closed cell foam is "not good" to use?

Pour in foam traps water against the hull unless you have some trickery to get it to drain properly. Over time the foam may become waterlogged.

 

[oops!]

Re: Transom Replacement Question

couple of things....

the pour in foam is good to use......but for the reasons above.....home builders on this site are tending to go with the foam boards in a non structural foam situation. foam in a tinny is non structural.

after removing the angle brace,i would cut the lower flange.... and either re rivet it back on after the installation... or just attach it to the angle iron when re placing. it is not a major concern with that big angle there. most of your forward transom pressure is taken by that brace.
re riveting in a tinny is also no big deal,

as far as aligning the new holes for the motor......after the new transom is in.......just re drill from the out side.....the holes thru the skin will still be there.
epoxy coat all holes you drill in the new transom.

 

[trailblazer2]

Re: Transom Replacement Question

Attached are pics showing work completed and "challenges/questions" remaining. As can be seen, knee brace and what I will call the "Z-angle support" have been detached from the boat by drilling out the rivets. It was necessary to cut away some of the flotation foam to remove the "Z-angle" and allow for inserting the new transom board. I cleaned off some of the surface "debris" with a wire wheel brush that exposed quite a bit of corrosion. I still have to remove the 2" angle brackets under the triangle corner brackets to allow inserting the new board.

I am still trying to decide on how to "re-install" the new transom board.{Because I cannot find a rental rivet set, I plan to use stainless bolts with self-locking nuts to reinstall the parts.} The original board was "attached" with a total of 18 rivets that were 1-1/2" long that went through the rear skin, through the board and then through either the 2" angle bracket or the "Z-angle".[see the pic with the 2 drill bits] In addition there are other "extra" holes for numerous other purposes [some known and some unknown] resulting in about 25 total holes in the skin of the transom. The only rivets that appear to ME to provide any structural support are the 4 in the "U" at the top and the 4 that attach to the top of the knee brace. That would eliminate some of my concern about how to drill the holes through the new board and encounter the existing hole in either the skin or the brackets.

QUESTIONS
1.Assuming there is no need to use more than 8 long bolts that must go through the new board, what is the "standard procedure" [or "best practice"]for filling all those other unnecessary holes? What about the corrosion holes?

2.Assuming that I DO need to anchor the board to the rear skin and the 2" angle braces attached to each side of the boat (to keep the rear of the boat hull from "spreading"), could one use 1/4" X 1" SS wood screws instead of the bolts??? [I an certain the "flimsy" "Z-angle" provides no structural support from lateral flexing.]

3.Regarding the 2 cracks in the transom top, will JB Weld work here or need to have welded?

Any suggestions/experience will be greatly appreciated!

 

[trailblazer2]

Re: Transom Replacement Question

Attached are more pics to go with my earlier reply

 

[ezmobee]

Re: Transom Replacement Question

I filled my extra transom holes with JB Weld and used little squares of cut aluminum flashing as "backers". That seems to have worked well and prevented the plugs from "popping". Those cracks don't look like deal breakers to me. They probably were caused by the failed transom.

 

[trailblazer2]

Re: Transom Replacement Question

does the JB-Weld also serve as the adhesive to hold the "backers" to the skin of the boat/transom??? Please elaborate on your recommended procedure on filling both the extra bolt holes as well as the holes caused by corrosion.

Ideas from multiple "experts" will be appreciated... and thanks to all who have responded so far.

 

[ezmobee]

Re: Transom Replacement Question

does the JB-Weld also serve as the adhesive to hold the "backers" to the skin of the boat/transom???

Yes.

The backers help hold some JB in place on the back side of the hole. Otherwise, once you sand it flush on the outside the only thing the JB has left to grip is the inside edges of the hole. This will eventually pop (been there done that).

 

[jasoutside]

Re: Transom Replacement Question

I have used JB like EZ there sans the alum flashing backer. I just schmeered on a thick layer and sanded smooth on the outside. You can take a look at the Jet Star thread in my signature round about post #464.

Cheers!

 

[jasoutside]

Re: Transom Replacement Question

I do think that EZ's method of adding an extra piece of flashing is good insurance.

 

[trailblazer2]

Re: Transom Replacement Question

Thanks for your input! Will use ss thru bolts. Have filled all unnecessary drilled & corrosion holes with epoxy putty and now ready to attach epoxy coated and painted transom board. Used some aluminum mesh I found at Ace instead of thin flashing.... seemed to work well.

Had a "brain storm" on how to seal the new bolt holes and prevent future corrosion due to dissimilar metals.... I am thinking of filling the newly drilled (drilled oversized??) holes in the wood transom with epoxy putty ( JB-Weld or equivalent) before inserting the bolts and making sure there is a layer between the washer and the outside of the aluminum skin. Will this procedure accomplish my objectives?? What "negatiives" am I overlooking? I feel this new board and hull repairs will last as long as the rest of this 1982 will

Apologize for "double posting" this question... it is also on my other thread about bolts

 

[barbosam]

You can use a plastic or fiber washer between the stainless washer and the aluminum. This is the same procedure recommended by armstrong when installing aluminum outboard brackets with stainless bolts.

Sent from my myTouch_4G_Slide using Tapatalk

 

[trailblazer2]

Re: Transom Replacement Question

I have drilled all the holes in the new transom board and bought my ss bolts and rubber washers to re-install.... turned out to not be that hard to hit the old holes on the opposite side... I have used up all my Gluvit coating on this and another board for my Porta-bote and none left to seal the holes in the board and the bolt heads at the skin. Now what??????

What is the best alternate material to seal the holes in the board?? I want to apply the sealant right before I insert the bolts. that is, I don't want fill the holes, let the sealant set and then redrill the holes.

Regarding the protective painting of the the epoxy (Gluvit) coated transom board, do I need to apply a primer first or just spray some Rustoleum paint directly onto the lightly sanded surface? [plan to paint the board, brackets and knee brace gray or silver]

 

[jasoutside]

Re: Transom Replacement Question

You used Gluvit to seal up your wood?

The best stuff to use in order to seal up fasteners is 3M 5200 (or 4200).

Primer is almost always a good idea.