Transom Cracks - Advice?

[handmeawrench]

Hi everyone. I have a 1987 c-dory 22' Angler, and it has cracks in the fiberglass where the transom meets the gunwale on both sides, right in the curve from horizontal to vertical. I have attached two photos to show you what it looks like.

At a minimum it's a route for water intrusion and must be sealed up. It may also be indicative of some structural issue in need of more serious repair like reinforcement using fiberglass cloth, or worse, cut out and replace.

At this point I'm thinking a couple layers of cloth right there would be a good idea. Or, is it worth looking into an aluminum transom cap? I know some boats have them, and it might protect the top edge of the transom pretty well. (I think most people just use aluminum channel and beat it into shape...can anyone confirm?)

I'm sure these photos are going to spark some memories (probably bad) and a story or two. I'd love to hear the thoughts of you experienced c-brats.

PS...The motors will be coming off the boat anyway due to a complete repowering situation, so removal for repair is certainly in the cards.

Thanks in advance!

[rogerbum]

The absolute first thing to do is to confirm/deny if the core of the transom is solid. Have you used a moisture meter to inspect it? Better yet, I'd probably drill a few test holes or grind out the fiberglass near the cracks to see what I find. It may be that the transom needs a lot more work than just a cap.

[Sunbeam]

From what I can see, I agree with Roger. The later boats (such as mine) have a back plastic transom cap, and from what I have read, things may not be super solid beneath it. I don't mean its weak, but just that for myself, when I remove the main engine at some point to overdrill/fill the mounting holes, I may also remove the cap, and if things aren't to my liking underneath it, I may fiberglass over the top of the transom (and then either reinstall the cap or finish it some other way).

I've seen that on the older boats the top of the transom was gelcoated, like yours.

At any rate, as Roger says, I would first want to ascertain that the transom is or is not dry (yours likely has a wood core). A moisture meter is a good start, but like he says, I usually find that core samples really tell the story, if there is any doubt.

On the cracks, I would want to sand/grind them down to see what you have. Sometimes cracks are "just" cosmetic; other times they go into the laminate. I can never tell without just taking material off so I can really see. Once I got to that point, I'd decide how to proceed based on my findings. I wouldn't be surprised if I decided to wrap the top in fiberglass.

Since you're going to have the engine off, perfect timing.

Sunbeam

[T.R. Bauer]

Who knows unless you dig into it. However, in looking at where the crack is, it appears to at least have started as cosmetic and looks to be opening up due to water intrusion. It could have gotten wet enough to delaminate somewhat based upon my observation.

With that said, I believe if it was a serious structural condition, the transom would be cracking in a completely different fashion. You'd have spider cracks running at oblique angles to the vertical plane of the engine, and where it all is glassed together in the transon where the splashwell and transom meet you would have much deeper cracking somewhat vertically.

Unfortunately, you will never know unless you grind into it or ready some test holes as others have noted.

[rjtangen]

Hello. I'm a friend of Handmeawrench, and the mighty 22' Angler which is the subject of this post happens to be sitting in my driveway right now.

Tonight I took a small screwdriver to that crack - the big one - to see what's in there. Some of the glass was loose, so I popped a chunk out and peeked inside. There was . . . . NOTHING. Void. Just air.

So I dug a bigger hole and looked in there with a light. There is a substance about 1/2" down that is firm and white, but breaks pretty easily. It's not unlike the pressed gypsum you'd find in drywall. Not quite as powdery, and a little firmer, but almost. Definitely not plywood, and definitely not polyester resin or epoxy.

Next I got out a hammer and whacked the screwdriver into that substance, aimed down. A chunk broke off. Still no wood. Did it again, deeper. Still no wood. One more time . . . I haven't found any wood in there yet, but the white substance is getting tougher.

A quick glance from the inside of the transom under the splash well and behind the tanks reveals that the transom plywood never did follow that radius up toward the gunnel. It's straight across on the top - at the same level as the top of the transom. It goes past the splashwell to the sides a few inches (outboard), but does not now, nor did it ever, go upwards inside that radius. My best guess is the white substance is a filler of some sort - maybe a Marine-Tex type product. There is obviously a previous repair there, identifiable by a slightly brighter white than the gelcoat.

It's bone-dry in there. Dusty-dry.

While I'm no expert at fiberglass repair, it seems that maybe we ought to just pump that void full of thickened epoxy, glass over the hole and call 'er good. The transom appears to be completely sound otherwise. No other cracks anywhere - inside or out. Tonight I stood on the foot of the main outboard and bounced my 250 lb. self up and down. That's about 550 lbs combined weight. The boat bounced on the trailer springs, but there was no perceptible movement anywhere in the transom. The knock test with a screwdriver handle reveals a very solid sound all over.

I'm not smart enough to post pictures here, but I'll email them to Handmeawrench and maybe he can make it happen. That void was a surprise to me, and I'd be curious if anyone knows what the heck that white stuff is.

Thanks!
Randy

[Sunbeam]

On my boat there is some white filler inside the splashwell molding. The reason I know this is from drilling out "cores" to overfill with thickened epoxy (prior to re-drilling smaller holes through the epoxy). Basically, if I drill from the outside in on the transom - above the splashwell - I get this:

1) Gelcoat on outside of transom
2) Outer fiberglass skin of transom
3) Balsa core of transom
4) Inner fiberglass skin of transom
5) White filler
6) Fiberglass of splashwell molding
7) Gelcoat of splashwell molding

So I think that - at least on my boat - some white filler was used as "core" where there is a slight gap between the inner skin of the transom and the splashwell molding. Since it's not two parallel skins (the splashwell is "shaped"), the filler was probably used.

I see that you are at the top of the transom, whereas my "core samples" ran perpendicular to the face of the transom, but the filler may be the same idea. Of course a 1987 boat may not be just the same as a later one.

Sunbeam

[handmeawrench]

Here are the photos rjtangen mentioned. Sure looks like some kind of 30 year old foam...

[Sunbeam]

I should have said that the white filler I mentioned is hard and has a slightly grainy texture. Something like if you used talc to thicken resin (not that I expect a 1987 to be constructed the same, but just because I should have described it more thoroughly).

[thataway]

It is fairly common for the C Dory's not to have plywood all of the way to the top of the transom--and in some of the 25"s to not have it go out to the edge of the transom at the level of the motor.

Your bounce test confirms that the transom is not rotten--and your finding of dry material shows that there was no moisture intrusion from the top.

Remember that the hull to deck joint is at the top of the transom, and in many C Dorys there was just a layer or two of mat over this joint, then painted on gel coat--sanded and waxed. In the newer boats there was the black plastic cap. I prefer the plastic cap--bedded in place--with no fasteners.

At this point you might pour a filler in there (Is it possible that in the past someone put Sea Cast transom filler in there?). Be cautions with too much either epoxy or resin, it can be brittle and generate a lot of heat during the curing process. I would wait until the motor is off. then you can route any plywood out 1/4" around the motor mount holes, and seal those with epoxy. At the same time you may get some clues of the rest of the transom build--if someone put Sea Cast in, or if there is wood further up at the center of the boat. I might even put foam in the void areas--if there is adequate structural support for the engine currently. If you are putting in a larger 4 stroke engine, then you may want to strengthen this area--and put in a mixture of resin and microballoons.

Definately rebuild the top of the transom, fron corner to corner, including the areas where the cracks are. I would use epoxy there, with a layer of 1708 cloth and then a couple of layers of 6 oz cloth. I would grind the glass on both sides to a taper and avoid a bulge where this new glass is scarfed in. Sounds like a good winter project. Keep us in the loop.