1980 four winns - wet transom

Pics

 

Did you just drill now ? If the drill just goes straight through to the glass, it is rotten at that point. If the outboard leg hits something, or grounds, it will want to pull the bottom bolts through the transom. You will need to ensure some backing, an angle bar of alloy or even a 3x2 where your mount holes are, will stop that, but if there is general rot away from the bottom mounts, the relatively thin outer glass skin will flex with no support behind it, under thrust.

 

No drill doesnt go through easily, feels like going theough wood.

Lateral edges of exposed area is mildly rotted at level of engjne mount holes. Seems loke due to water tracking along length of transom wood

 

Doesn't sound too bad, I can well understand you don't want to gut it, it is basically uneconomic and too much work in a cramped environment. You just need to be safe. What I think I'd do, is use a hole saw, maybe about three inches, and centred on the two bottom mount holes, carefully cut through the ply from the inside, leaving the outside glass undisturbed, Prise the centre out, clean up the surface of the glass and install a replacement cut from the same thickness of waterproof ply, with the same hole saw. Use an epoxy filler to bed it in, that should stop rot spores migrating through to the new piece. Then apply a thick piece of ply to the entire area you have exposed, using thickened epoxy, ensuring first that it has dried out, and been sanded. You should use a few bronze boat screws, into the old transom ply, to hold it is place while it sets up, and leave them there to add some strength to it. You may need longer bottom bolts though. You should then have catered to both tensile and compressive forces.

 

Thanks. Sounds good. I have drilled more holes lateral to this area, along the floor line and the wood looks good on drill bit.

 

OK, I think you have established that it isn't "shot", so a localised repair can be practical. You don't need to use glass to re-encapsulate it, just add the solid ply to the existing, and paint it afterward to seal it.

 

Thanks. Would it be useful to laminate woth biaxial on inside tabbed into floor and bilge area?

 

If you haven't cut away any more of the glass than was shown in the pictures, probably no need. Just make the added ply a big piece cut to the shape you can see, to spread the load. You'll add a little weight, but not enough to be a problem. With the old ply coarse sanded, and the additional piece screwed and epoxied to it, should be strong. But you need something solid to act as a compression sleeve, hence the 3" circular inserts. You can glue the new ply up to the old glass where that remains, don't cut that away any more, just feather the rough edge with a sander.

 

What thickness plywood? Shall I cut a piece that runs out past the area exposed?

shall i continue to run heater at this area for a month or so to dry out?

 

Yep, dry it out, and use as large a piece as you can fit in, at least 3/4 in thick waterproof ply. Be careful you don't set the boat alight with the heater ! Your transom will probably be 1.5" thick, so two thicknesses for the part you drill out around the mount holes, to get it flush before overlaying with the new ply, probably. Use some coarse thread self tapping screws to attach the sheet of ply, and to hold it firmly in place while the epoxy sets up. bronze boat screws would be best. I don't see much point in glassing over it, but if you do, mat would be easier.

 

rather than waste $ on electricity for a heater, you could use some kind of desiccant in that space, there are various kinds that soak up moisture in confined spaces. Put plenty in there and it should dry it out.

 

Do you think that this whole transom will dry out with a few months of heat? In the exposed areas i have noticed significant drying out to depths at least .25” since pulling off the chopper laminate in a weeks time

 

So, on further thought I'm wondering if it makes sense just to replace the transom. I have plans to use this boat out on lake huron again next year (generally just to cruise 25mph, but sometimes in pretty rough wave action), and Im thinking that I ll be worried about this transom if left as is... I could just dump this boat and get another, but getting something used seems to guarantee that another such situation is likely with the next boat. Also, this boat is a nice runner. It handles rough water (had it out in 3-4' seas this summer) well beyond my expectation for a 16 footer (coming from my saftmate 15 it is night and day a better boat).

If you all believe this is the best route, I need to ask why transom repair from outside isnt a good option. To do this from the inside will require pulling the boat cap (cannot see how I have ability to do this at home) or cutting the splashwell component and removing. Id rather have any poor cosmetics of my repair to show on the transom outer skin than on the gunwales of the boat. Would do weigh in on this again?

Thanks alot

 

Transom removal from the outside requires glass tabbing into the neighboring skins which means removing gelcoat; perhaps from the hullsides and bottom if margins are insufficient for say 8" of glass tabbing all around the core replacement margin.

If you simply work on the inside; you can glass the inside with 12 oz biax and epoxy if you want some strength. Say 5 layers after core work. That would be strong and require no finesse and finicky finish work like fairing. Fairing and gelcoat would take longer than the replacement work.

if access is troubling; you can wet out 1208 on a table and bring rolls of it (on cardbord tubes) wetted to the boat and lay them on. Make sure to precoat the ply core and make sure it is flat and filled and sanded flat before laying glass.

Make sure to wrap the neighboring sides and hull bottom and even splashwell or deck if you are able.

it seems easier to work from the outside, but it is about 4 times the hours...

 

Boatworks Today has a great video on an exterior transom repair on a Bertram 25 or 28. I encourage you to watch and remind you that the video is shortened, a lot.

The boat he was working on is not an o/b iirc, so his repair did not wrap beyond the transom plane. And he is a gelcoat/ester expert.

There is a lot of strength in the exterior skin that you have no business messing with for your situation. It would be better to take it to a repair shop if you have issues working inside due to your size or claustrophobia, etc.

If you do the repair inside; you may want an organic vapor mask or you could also run a shop vac blower into the cavity as it will get pretty smelly in there. For that reason and your strength wishes; I'd use epoxy.