How do you know if a transom needs repair or replacement?

[Todd in NY]

My boat is a 1987 Sea Nymph center console 191 with 2 outboards (90hp and 15hp). It has the protected transom/splash well. It seems solid, but given the age of the boat I just wonder about things like that. How do I know when it's time to replace or repair the transom?

[MCF]

I have a 1986 Sea Nymph 19, I had the transom replaced three years ago because it needed it quite badly.  The problem with the Sea Nymph is it is not easy to inspect the wood in the transom because there is no easy access to it.   Knocking on it, particularly on the inner side of the transom was one way I determined there was a problem which was confirmed by taking off the old motor(I was switching motors at the time) and inspecting one of the bolt holes.  My boat prior to my ownership also spent several years out in the weather.  A boat stored inside most of the time is going to delay the weathering/aging process.

 

Send me a PM is you want any further information.

 

Mark        

[Todd in NY]

Yours might be like mine, it has aluminum on both sides (front and back), plus a flat aluminum rail that covers the wood across the top. But that aluminum piece isn't water tight, so when a wave comes in over the short transom it can seep in under that aluminum. In rough water, with the boat slamming onto the next swell, it seems to really pound the motor on the transom. It doesn't look loose, but I worry about it because of the age of the boat. I'd rather be safe than sorry.

[MCF]

That is correct, water constantly is in the well in any type of wave-  that was the area which upon investigation found there was a problem. You can always drill a small hole or two on the inside, enough to get the aluminum clear and see what you have.  If it is bad it will be very brittle and look and feel like a waffle material. 

[Todd in NY]

It looks like the wood can be replaced without removing the aluminum on the front and back. I'm thinking that if every bolt was removed (motors, transducers, etc), then remove the flat aluminum rail/cover, that it might be possible to pull the wood core out. The top rear corner braces might have to come off too, but it seems so much easier than removing the aluminum covering. Is that how your transom was replaced, by just removing the wood core?

[jimski2]

I believe it is possible to reinforce the transom by adding two additional transom plates added to the transom. I saw Coast Guard boats with no wood but triple plated aluminum about three quarter inch thick with double outboard engines mounted on them.

[rolmops]

If your boat is on a trailer, raise the outboards and grab the center outboard and try to jerk it back, forth and sideways. and the same with the kicker. If you feel some give or see the transom bent in and out or sideways then you know  that it is time to replace wood inside. Most transoms have never been painted by the boat maker. that is why they rot.

Replacing one is quite simple ,but time consuming. You will have to remove the engines,everything that is screwed into the transom and all the bolts that hold it. Get yourself a big piece of cardboard (bigger than the transom). Now alone with some winch like thing or with a human winch (friend) work the old transom out of its spot ( a crowbar may come in handy) and ,once removed, lay it on the cardboard. Now you can draw the outline on the cardboard.

As for replacement materials. There is a liquid material on the market that is expensive,but you can just pour it into the transom housing where it will harden and your new transom is ready to go. The other way is to buy 3/4 inch 8 ply plywood and glue and clamp two pieces together in order to make a standard  transom thickness one and a half inch thick piece of plywood. I like to use  the marine grade plywood, but it has to be a good quality material and not pressure treated.Marine plywood is very solid and has very few holes in the ply materials. There is other material on the market that is just as good. Now using your cardboard, draw the transom shape on your plywood and cut it into the measurements you need. Lower it into the transom housing to see if it fits right. Now just take it back out and seal the plywood with   (quite) a few layers of paint or glass it in. If you intend to glass it in you may want to use 5/8 and 3/4 inch plywood. This will give you a bit more play so you can do heavier glassing. I found though that the material tends to soak into wood and does not really increase the thickness,unless you use 3 or 4 coats.

When everything is ready to go back in, lower the by now quite heavy new transom into its place ,but make sure that there is an inch  or two on the bottom that stays open so the bottom of the transom will not constantly sit in the bilge water. Now it is time to drill new holes using the holes in the aluminum frame and screw the whole thing back together. When that is all done ,start taking out some bolts at a time and seal the inside of the newly drilled holes so no water can penetrate into your new transom through those holes.I used m5200 but others glass those holes. When you have finished all that you may look at the bottom of transom and wonder why you did not  do a fix on all those pesky little holes which you drilled in the bottom of the transom for the transducers and whatever else you installed there. I know that I did. But in order to prevent that, you can just buy some aluminum plating , cover it with m5200 and while the transom wood is not yet in place just stick the aluminum plate(s)inside the transom housing to cover those  holes. It helps to take pictures before during and after your project.

Good luck.

[Todd in NY]

I believe it is possible to reinforce the transom by adding two additional transom plates added to the transom. I saw Coast Guard boats with no wood but triple plated aluminum about three quarter inch thick with double outboard engines mounted on them.

Good point about the coast guard boats. I've never seen one up close, so I didn't know they used all-aluminum transoms. Makes perfect sense though.

[Todd in NY]

Thanks for all the great tips and advice Rolmops! I maintain my boats as if I'm going to keep them for a lifetime, so if I ever sell it, the new buyer will get a very reliable, well maintained boat.

[Frogger]

Todd, here's a good sign when needing one, I was taking on some water when out with the water being a reddish color, couldn't figure it out until I took the cap off. Found lots of corrosion spots thought the aluminûm. Ended up using a product called Seacast. Like others have said it's easy but time consuming. I would say if it were me, no water leaks, engines seem solid when you move them, go another year and check again. Mine was a 93 19 GLS. Hope it helps.

[Todd in NY]

Thanks Frogger, I'll look into the Seacast product. I take on a little water during a 6 hour trip on a calm inland lake, but it's never enough to make the bilge pump turn on. But on Lake O, fishing in 4 footers, the water comes in through the 2 rubber boots that I want to replace before next season. I also want to re-caulk that splash well area just in case there is water coming in through the caulked seems.

[jimski2]

Check out the Hull Truth site for trans repairs

[Todd in NY]

Will do! I've looked at a few other forums like I boats and tin boats. I talked to a local boat repair guy who works at a nearby marina. He's a friend of a friend, so I think he would give me a reasonable price if it turns out to be something I don't want to tackle on my own. The job seems pretty straight forward, but only with the proper tools, equipment, work space and time. Either way, it can't happen until April anyway due to our unpredictable weather, and the fact that I don't have a garage that my boat will fit into. That gives me all winter to think about it.