Rotten Dinghy Transom - Suggestions?

[Bugsy]

This is a ~60 year old fibreglass Albacore dinghy.  It is sailed recreationally.   

The transom appears to be fibreglass over plywood.  The plywood is rotten.   The arch over the opening for the tiller is broken and is only held in place by the traveler.   

Everything still works and the boat is functional but I would like to do something about this.  Easy and low-cost are preferred options.  One option would be to just cut the arch off and glass the transom flush with the aft deck.  I could then install a bridle to support the mainsheet block.   A functional traveler is not required.  

Anyone have any useful ideas or suggestions?  

 

[steele]

I did a similar repair on a rowing dingy. In your case you could cut the deck layer skin off and try to preserve the arch, or as you say just cut the whole thing off flush, either will work for casual use. In my case the transom plywood was rotted amost to the bottom of the hull. Rather than pulling the skin off the outside or inside, I just dug as much as a could out using long screwdrivers and other inappropriate tools and then put a few heat lamps on it. After getting it pretty dry I flooded the space from above with epoxy thickened with microballons, adding bits of new plywood to take up some space in the void to reduce the amount of epoxy needed.  The end result lasted for years, even allowing use of a small outboard on the transom. If you go this route you could sink bolts with a large nut on the end for the bridle mounts while the epoy is wet.

Bridles work fine for lasers, laser 2s and I am sure other dingys, but you may be able to straiten the track you have an bolt it back down.

 

[cyclone]

Granted it’s meant for a powerboat transome but it should give you a basic approach to go by

https://www.epoxyworks.com/index.php/repairing-fiberglass-powerboat-transoms/

 

[See Level]

Take the traveler off completely and use an amsteel bridle.

Fix the rest as desired.

 

[Irrational 14]

You should check how far the transom has rotted down. It’s always where water is trapped for long periods. In this case deck to transom joint but I’d also check hull to transom joint at the bottom.

If it’s all mush, the transom will have to come out and a new one put in. Uninstall your rudder fittings off the transom. If there is moist or black wood particles coming out with the fasteners, it’s gone.

 

[asmo]

I did just like steele described for the little rowing dingy we keep tied to the dock. Cut my hands pretty good scraping ALL the rotten wood out from between the fibreglass inner and outer skin. Made a new plywood transom, and embedded it in thickened epoxy leaving an inch or so of solid epoxy at the top. Four(ish) years and zero maintenance later it’s holding up great. If I had another rotten transom to repair I’d do it exactly the same way.

 

[Bugsy]

Thanks, everyone.  Appreciate all the responses. 

For the bridle, I am thinking of setting a pair of stainless eyebolts in the transom, like below, as I rebuild.  Anyone see any problems with that?

 

[GoldenStreak]

That looks alot like my ancient Whitby Albacore.  Someone had updated my traveler with a harken and used those at the corners because the car had sheaves.  Anyway it looks alot cleaner when people just poke holes with chafe protection and lead the bridle through the holes.  The same holes your going to drill for the eyebolts anyway.  I'll see if I can find a picture of what I'm talking about.

 

[Diamond Jim]

Most likely the entire transom core is mush.

I’d remove the outer skin, ‘cept the edges,  and the mush, clean up the inner skin, and rebuild, using foam core  with hard spots of coosa board or strong epoxy putty for the rudder hardware. 

A bridle traveler will work fine. 

 

[Zonker]

I'd build a brand new foam core/glass transom. Lay it up on a smooth mold table. Trim. Glass to hull and deck (I assume you can get to the inside trandom/hull joint) 

Then you only have to fair the external taping and waste hours scraping out old rotten plywood. 

 

[GoldenStreak]

My Albacore, Whitby 2340, the transom is mostly skin with the plywood part shaped like a "T".  Basically the plywood only supports the traveler over the hole for the tiller out to the corners and in the middle under the tiller hole down to the bottom to support the tiller hardware.  That strip is only like 4 inches wide if memory serves.  Of course someone may have modified mine over its many years.

 

[Grrr...]

I'd build a brand new foam core/glass transom. Lay it up on a smooth mold table. Trim. Glass to hull and deck (I assume you can get to the inside trandom/hull joint) 

Then you only have to fair the external taping and waste hours scraping out old rotten plywood. 

It may be more work than the boat is worth, but this is what I'd do as well.  Just finished it on a S2 7.9 and that will last the rest of the boat's life since it was done right.  Grab a dremel and start cutting back until you hit dry.  Rip out the old core, replace the new.  Use marine ply and cut a piece that makes you happy for that fancy tiller cut out.  Smack some bog and 2 or 3 layers of glass on the whole thing, sand, then paint the whole stern.  It's a week or two job if you're doing it at home.

 

[See Level]

Cut and peel the transom skin off  2 or 3 inches in from the edge, dig out the rotten ply an replace with new core as needed, glue the skin back on.

Probably don't need the arch.

 

[Bugsy]

Update:

Yeah, the transom probably needs a re-build. In the interim I cut off the arch with a Sawzall, installed some hard points attached to the transom with angle brackets, made a bridle out of some old rope and went sailing.

I put down a layer (or 2 or 3) of fibreglass where the arch used to be to protect the wood underneath.

Thanks everyone for the input.

 

[Steam Flyer]

Depending on the extent of the rot, and how perfect the desired result, mulitplied by how hard you want to work, equals a range of answers. Glad to see you got the boat sailing again. Bonus points for a fix that will absolutely get you into the Dreaded Previous Owner Hall Of Fame... personally I try to avoid those, but as I get older the quest for perfection seems more and more like a perverse waste of time in itself.

Molding a new transom is the best, but you will also need to spend considerable time & effort on providing index points on the deck and hull so you can get the new transom positioned perfectly. Then arises the question, do you want it crooked like the old transom undoubtedly is, or PERFECT?!?

Next best would be to remove the skin of the transom, provide a new core, and lay-up a new outer skin. I've done this, it's about as much work as making a perfect new transom on a table and trying to install it.

Here's what I've done, our high school sailing program was donated a bunch of Oday Javelins which are all from the 1970s (older than the kids' parents) and most of which had rotted plywood-inside-fiberglass transoms:

Take a 3/4" (or close) plug cutter that you don't mind ruining. Find the rottenest spot on your transom, cut the skin off with the plug cutter. You will see black oozy crud, don't be alarmed. Now lay out a pattern to cut these holes with about 2~3" between them. Follow that pattern out until you either get to the edge of the transom or the edge of the rot.

2- Now get a small Allen wrench or a dentists pick or some little slightly curved tool you can dig out the soft rotten black mush. A thick guitar string in a drill actually does some good. Put down a drop cloth, this makes a disgusting mess on the shop floor. Be careful with the mush because it will also have fiberglass splinters mixed into it.

4- Now mix up some putty to pack into the transom. I use epoxy with the cheaper low-density filler, mixed with cut strands of fiberglass (I have a bucket of this annoying stuff in my shop). I've mixed in foam beads from cheap foam insulation or blue sawdust from cutting blue insulation board. The goal is to get a mix that is -just- -barely- runny enough to settle in place. Painters masking tape over the lower holes as you fill it up.

3- Before you start packing gap with goop, make up a cross-piece that you can clamp across the transom to keep it flat while your filler goop sets. I have a wavy-transomed Oday Javelin to show why this is desired.

5- Wait for the goop to set HARD, the sand the heck out of the transom and lay on a light (6oz or so) fiberglass skin. It's satisfying to put small patches on each hole but it's a lot more work and not really necessary.

6- Paint to desired finish.

7- Reinstall hardware into newly-strong transom. Beware that any tackle or purchase based into the new transom may pull hardware off another part of the boat, now that it's STRONG and less flexible.

This actually isn't as big a job as it sounds.

 

[nota]

I did an airex transom on an older Bahama popoff of a champion dinky
it was the best 1 piece popoff I have ever seen all cloth on a smooth hull even smooth out side from a male mold
of a 12 1/2 ft racer wood local built for their festival races
some one spent effort on that popoff
but the plywood transom was rotten

simpler access as no deck with rope traveler
but you can pre glass the foam and get a better smooth look on a
bench and just tape the transom in place after doing the flats

likely was too good to be left on a public dock as that one disappeared in a few months even with my crude seats and rail
we learned the art of de- yachting dinks to reduce theft

 

[slug zitski]

Thanks, everyone. Appreciate all the responses.

For the bridle, I am thinking of setting a pair of stainless eyebolts in the transom, like below, as I rebuild. Anyone see any problems with that?

Eyebolts always twist and leak

better to use a pad eye