Achilles Rotten Transom

[albe]

Hi there,

I got a 12' achiles rib last year and have only powered it with an old johnson 15 for a few trips.I assumed the boat would have had composite or plastic transom "guts". Upon inspection I found out the transom was rotten(no cracks or anything tough).

Recently I decided to cut the cap off to verify its state and I could spoon out the plywood...

I did loads of googling on how to fix it but what I found mostly pertains to non-inflatable boats.

I am currently thinking to continue to hollow out the transom from the top then I could custom cut a couple peices of plywood, coat them in epoxy then slide them in from the top. Does this sound like a reasonable approach?

--My only concern and my principle reason for posting on this RIB forum is that; My friend mentioned that there might be mounting tabs for the tubes inside the transom? Should I watch out for these if gutting the transom from above. Or anyone with rib-transom-fixin' experience have any wisdom to share;like- just remove an inside fiberglass piece from the transom and replace the plywood that way?

Thanks,

[ribber]

If you can manage to scrape out whatever is in the void (plywood), why not just pour this type of product into the gap. Allow it to expand, cut a neat line across the top when set and cap off with a decent stainless steel 'u' channel. Allowing enough depth of channel down the transom each side, so you can bolt through the engine bolts.

https://www.youtube.com/watch?v=5DlQNgIsuj4

[albe]

thanks ribber,


I was thinking of using one of those pour-able transom compounds (like seacast or arjay etc,) That was first time I saw the foam. - I will look into it.


I was just wondering if I have to watch out for mounting tabs for the tubes in the guts of the transom? or are they simply held on by that 4" wide hypalon tape that goes on halfway on the tubes and transom and floor on the exterior?

[Nasher]

Originally Posted by albe

I was just wondering if I have to watch out for mounting tabs for the tubes in the guts of the transom? or are they simply held on by that 4" wide hypalon tape that goes on halfway on the tubes and transom and floor on the exterior?

The tubes will be fixed to the transom exactly as you suggest with the strips of Hypalon.

Nasher.

[GuyC]

With foam cores, you have to be careful about failure due the shearing in the core. When the transom bends, the inside of the transom is in compression and the outside is in tension. The core has to resist this and foam cores aren't that resistant.

It may work but ply is much more resistant to shear.

[ribber]

Good point about flexibility, perhaps add a layer of ply on the inside face. I guess only smallish engine, so not massive torque involved.

[beamishken]

Usual method of repair is remove the glued strips holding the tubes to the transom then cut the inner skin of glass away and replace the ply then reglass the inner & restick tubes
Plenty of refurb threads on here to give more details
Dont be tempted to shortcut you will probably regret it later