aluminum transom: anyone built an all aluminum transom no wood. On a larger aluminum vessel like 22’

[the brain]

aluminum transom: anyone built an all aluminum transom no wood. On a larger aluminum vessel like 22’+.

Where I messed up a couple times w/ the plywood.My orginale plywood transom appeared to be 2” thick

It mite have been swollen. I believe Starcraft didn’t use ¾” plywood I think it was 3 layers of 5/8” which is 1 7/8.

The flange this plywood sits in was a tad smaller than 2 “ BTW orginal transom was in pretty good shape it was painted on exposed inside.

1. I actuely had to grind down the thickness around the perimeter of wood to get it to slide into the flanges.

2.The lumber seller didn’t have ½” marine grade plywood. Sold me ½ regular I thought well I’m sealing it anyway this 1/2 failed on star in small section. took 10 years the marine ply is still fine. wronge.

3.glued all 3 plywoods together w/ construction glue, lumber place say it was waterproof wronge.

4. sealed w/ cheap urethane from home depot wronge.

5. I had to cut the transom skin off the vessel to remove the transom. left the star side half exposed used 5200 on the top of this star side wronge.

I sealed top of port side w/ 5200 an fabbed not that great of a cover but keep rain off wood a new aluminum transome skin this port side isn’t rotton.

I’m now wanting to fab complete transom in aluminum.

I have some scaffolding platforms that appear very strong I beam.

this material is a tad short horizontaly for middle piece mite fit into transom flang on lower piece.
middle piece barly reachs to lift rings

will use 1/2" thick aluminium for vertical whalers where though hulls go though engine pod an though lift rings.

will cut a section for the upper transom section.

look close at the platform I believe it's keyed to fit another platform which ties them together.

I did this transom 10 years ago she held up kindof good but w/ the cost of marine plywood I would expect three times 10 years. she be used this season as is. but I want a stronger more durable and definity liter transom bc I'm adding some weight back there. thanks for any advise.

 

[montero]

It will be tricky to manufacture transom out of this panels.You will cut of asymmetrical parts from each panel , weld them together.
T-reinforcements vertically . Thats easy part.
Next is dimensioning and designing the edges of this transom so that it can be cleverly connected to the hull .
What is the thickness of the aluminum on the bottom and freeboard?

Once I did make sandwich ply-herex-ply transom. Small boat , reinforcement at engine clamp was made of aluminium rings.Solid plywood at this area also will work.

 

[montero]

Cut here schafold plateform I beam stronge 1 — Postimages https://i.postimg.cc/nLgDbz6H/schafold-plateform-I-beam-stronge-1.jpg

 

[the brain]

I don't have to use these I/beam panels just thought they would be way stronger than plywood at a fraction of the weight.

where I seroiusly messed up was not covering the star side where the rain started to rot the middle regular ply mainly at the top. also a little rot on inside exposed ply also on star. top an exposed port is uneffected.
for short term I plan to treat the top an exposed rotton ply w/ this. https://www.amazon.com/TotalBoat-Pe...6f7e0ee0265ff7e6af60b34&ref_=as_li_ss_tl&th=1

and of course fab a top cover.

when I get around to redoing the complete transom I'll use 3/4" X 2 is 1 1/2" which should slide into the transom flanges. new marine plywood soaked in the total seal stuff. then use the I/beam panel behind the ply for top pod mount bolts.

what do you think of the total seal.

 

[montero]

I don't have to use these I/beam panels just thought they would be way stronger than plywood at a fraction of the weight.

where I seroiusly messed up was not covering the star side where the rain started to rot the middle regular ply mainly at the top. also a little rot on inside exposed ply also on star. top an exposed port is uneffected.
for short term I plan to treat the top an exposed rotton ply w/ this. https://www.amazon.com/TotalBoat-Penetrating-Epoxy-Quart-Traditional/dp/B00J36WRV2?crid=1Y219QK6YMD0K&keywords=penetrating+epoxy&qid=1675795006&sprefix=penetrating+epoxy,aps,108&sr=8-1-spons&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyODJBWFVUVVkxSjM2JmVuY3J5cHRlZElkPUEwNzM2MTAzMlRJUTdGOTdWTlFLMSZlbmNyeXB0ZWRBZElkPUExMDMyMjA4MklIRllZMTdNWDNZMCZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=&linkCode=sl1&tag=goodviewwoodw-20&linkId=500f5315c6f7e0ee0265ff7e6af60b34&ref_=as_li_ss_tl&th=1

and of course fab a top cover.

when I get around to redoing the complete transom I'll use 3/4" X 2 is 1 1/2" which should slide into the transom flanges. new marine plywood soaked in the total seal stuff. then use the I/beam panel behind the ply for top pod mount bolts.

what do you think of the total seal.

For short term you can cut out the rotten parts and paste new ones using glassfiber fabric . Did you check transom between flanges ?
Total seal is probably good for priming.

 

[the brain]

yes I checked inside the flanges thats where the rot is on both sides mainly on the bottom flange.

remember I messed up making the transom 2" so I had to cut an reduce it's size additionly I may have not treated this cut areas w/ the fiberglass resin purchased at walmart.

the rest of transom is soild minus the star small section propablly 5" across x 5" deep. now I haven't removed engine pod to inspect directly behind knee brace but the bottom of knee brace is solid.

still wanting to avoid complete transom redo plus still undecided on a complete aluminum transom.

.thanks again for advise