Transom Question

[viper123]

So, I have a 97 viper cobra 201D. Had it out a couple weeks ago and thought I noticed slight movement in the transom. Took it by a buddy of mine who's a marine tech. He had me stand on the cavitation plate and when I did, there was very slight movement if I jumped a bit with my weight on it. Not a literal jump, but you get what I mean. He looked at the transom and told me the transom itself looked solid and not rotted, but that the movement was from where the knee braces attach to the transom. Said he didn't think they did a great job putting a lot of glass on it towards the top of the knee brace. I peeked in there and did see a couple stress cracks on both sides of one of the knee braces at the top. Now I have another buddy that does glass work. He said he could add more glass around the knee braces , and how he does it should be plenty strong enough to fix the issue. I'm just wondering if that sounds like the way to go, or a bad idea?

[BILL LO]

I would go by your buddy's suggestions , sounds like both are specialist in the marine industry

[viper123]

Well, the one tech works on motors, not so much transoms. although hes been around the industry for a long time. The fiberglass buddy, I should have said, is in the automotive industry, so isn't an expert on boats. But is a good fiberglass guy. I figured some of the guys on here that are transom specialists, have seen a situation like this and could tell me if just glassing over the knee braces to the transom would be strong enough.

[geobass]

97 Viper Cobra.....I would bet that the transom is rodded out. If you love the boat and it's paid for then I would have transom replaced with a composite transom. Est cost 4-5 thousand depending on how important it is to you to have it match the color and flake on the boat.

[rojoguio]

When I survey a boat for a customer I bring a very small plastic urethane head non-marring hammer. You can tap around the transom and if you tap a soft spot you get a thud. Good transom sections have a sharp crack, it sounds solid, you will know the difference in the sound. Almost every transom job through my shop the owner represented than the transom wasn't that bad. I pull out the hammer, tap around, you can immediately tell how much of the transom is soft. I use a wax pencil to mark the thud spots until I tap over the whole transom. That plastic hammer has exposed more rot in transoms than the owners thought they had. Give it a try.

Soft spots can be cut out and fixed without cutting the whole transom out..........usually I cut the whole thing out since I have to warranty the work.

[viper123]

That's what the tech did when I showed the boat to him. He tapped all around on the outside and inside of the transom and couldn't find any areas that he could see that was rotten. He didn't take any core samples or anything like that. Then he saw the stress cracks on the top of the knee brace and said that it wasn't glassed as good as it should have been. I'm just trying to figure out if re-glassing the braces would help.

[rojoguio]

Pictures help here, that being said properly adding glass to reinforce the braces sound like the normal repair. If the transom sounded out solid reinforcing the braces at the stress area is how I usually attack the problem. You need to stop the movement. Long day today, I miss read your original post.

[viper123]

https://postimg.cc/gallery/ov1n0wla/

[viper123]

Those pictures are of the left and right side of the knee brace that has the issue. The other knee brace had no cracks. You probably have to zoom in to see the stress crack.

[Bassnailer]

Since winter will soon be upon us, if it were mine (actually, I did this two years ago to my own boat) I would remove the motor (you don't have to unrig it, just use an engine hoist to swing it around off to the side so you have room to work) then pull off the jack plate, any transom trim cap plate, rub rail at the back, and remove all the through hull fittings. You will be able to survey the wood in several spots this way and tell for sure that the wood is solid. If the wood has some excess moisture in it but is in good shape, you have a couple of weeks of down time during which you can dry the wood out with heat lamps. If, or once, the wood is dry, then you can have your fiberglass guy beef up your knee braces and while he's at it fiberglass that seem between the cap and hull shut so you don't have to worry about any water in the future. Replace all your through hull fittings (even the drains that are pressed in, I'll even let you borrow my tool to press the new ones in) seal everything with 3m 4200 and bolt the engine back on. You will then have a water tight hull and piece of mine. I had a transom go bad on a different boat, and I felt the one I have now was like a ticking time bomb until I took a couple of weeks in the winter to really seal everything up right. I don't worry anymore, I now know it's good and after a few more years I will repeat the process.

[rojoguio]

The pictures are great. It looks like the reinforcement fabric is all chop mat. The seams are easy to see. Notice the sharpness of the right angles, I don't think on the side cracked it had much fabric there. Certainly not a proper lamination. A hard strike years ago could have cracked the one side allowing it to work a bit. The gelcoat cracked on the other side may not have even cracked if the other brace was solid. Proper prep grinding, all the gelcoat must be removed in the repair area, a fillet mixed with either vinylester & talc or 10X better, West Epoxy & 404 High Density (Milled Fibers) to mayo consistency applied to radius the right angle enough to allow the reinforcement fabric to lay properly, should be applied first. The advice about poor lay up is correct. I personally like using 1708 and epoxy for this type of repair. All the Champions I fixed rotted from the seam on the top. Usually although it looks like the seam between the cap and transom is not attached when the cap is set on adhesive is applied completely bedding the two together. When I pull a cap separating this point is always the worst part. Your transom may be stretching in the center due to lack of anchor from bracing. Pulling drain tubes, jackplates, engines, etc to allow access to the core to check for water is much easier, less invasive, and can be very telling for prevention or repairing. I don't do it since by the time a customer brings me their boat it is for an estimate for repair, the damage is already very obvious. I had a 24ft Champ CC that only had 2 of the 4 bolts visible from the inside. Very easy to see the problems.

[viper123]

Since winter will soon be upon us, if it were mine (actually, I did this two years ago to my own boat) I would remove the motor (you don't have to unrig it, just use an engine hoist to swing it around off to the side so you have room to work) then pull off the jack plate, any transom trim cap plate, rub rail at the back, and remove all the through hull fittings. You will be able to survey the wood in several spots this way and tell for sure that the wood is solid. If the wood has some excess moisture in it but is in good shape, you have a couple of weeks of down time during which you can dry the wood out with heat lamps. If, or once, the wood is dry, then you can have your fiberglass guy beef up your knee braces and while he's at it fiberglass that seem between the cap and hull shut so you don't have to worry about any water in the future. Replace all your through hull fittings (even the drains that are pressed in, I'll even let you borrow my tool to press the new ones in) seal everything with 3m 4200 and bolt the engine back on. You will then have a water tight hull and piece of mine. I had a transom go bad on a different boat, and I felt the one I have now was like a ticking time bomb until I took a couple of weeks in the winter to really seal everything up right. I don't worry anymore, I now know it's good and after a few more years I will repeat the process.

great idea. I have already pulled the splashwell drain tubes and looked in there. Dont see any rotting. Ill see if my buddy has room for me to keep the boat in one of his shop bays for a couple weeks or so. I can pull the plate and such before he does the glass work. Thanks for offer on special tool. Ill check with my other buddy at the marine dealership if I can borrow his first.

[viper123]

The pictures are great. It looks like the reinforcement fabric is all chop mat. The seams are easy to see. Notice the sharpness of the right angles, I don't think on the side cracked it had much fabric there. Certainly not a proper lamination. A hard strike years ago could have cracked the one side allowing it to work a bit. The gelcoat cracked on the other side may not have even cracked if the other brace was solid. Proper prep grinding, all the gelcoat must be removed in the repair area, a fillet mixed with either vinylester & talc or 10X better, West Epoxy & 404 High Density (Milled Fibers) to mayo consistency applied to radius the right angle enough to allow the reinforcement fabric to lay properly, should be applied first. The advice about poor lay up is correct. I personally like using 1708 and epoxy for this type of repair. All the Champions I fixed rotted from the seam on the top. Usually although it looks like the seam between the cap and transom is not attached when the cap is set on adhesive is applied completely bedding the two together. When I pull a cap separating this point is always the worst part. Your transom may be stretching in the center due to lack of anchor from bracing. Pulling drain tubes, jackplates, engines, etc to allow access to the core to check for water is much easier, less invasive, and can be very telling for prevention or repairing. I don't do it since by the time a customer brings me their boat it is for an estimate for repair, the damage is already very obvious. I had a 24ft Champ CC that only had 2 of the 4 bolts visible from the inside. Very easy to see the problems.

Thanks for looking at it and for that info and advice. Very Much appreciated.