View Full Version : outside of the transon needs cleaned

01-07-2011, 06:59 PM
Hi all! newbie here, On the outside of the drain holes on my transom needs to be cleaned,can anyone tell me the best way the clean this rusty colored stain up?Actually my other boat has it too! Might as well do both of them at the same time........any suggestions will be much appreciated...I hope I dont have to repaint it if it can be cleaned up..........attached is a pic

01-08-2011, 05:34 AM
There is a liquid cleaner called CLR (which stands for Calcium, Lime, and Rust) which should do the job. You can find it in most hardware stores. Be sure to re-wax the area after it has been cleaned.

01-08-2011, 05:51 AM
Thanks chawk_man much appreciated,I had a feeling that there must be something to clean it. I have the same thing on mt Larson too. Both boats have been only used in fresh water, never been in salt water, but they have been like this since I have bought them.The one that is in the pic is my 19 ft.Cobalt and I had just bought it and it had been sitting in a farmers old barn for the last 20 years and I am just trying to get it back in shape,I will be doing all the teak wood next. The rest of the outside of the boat is in excellent shape(paint is like new,just need cleaned) no scatches........any way thats for your help

01-08-2011, 06:14 AM
Hope that helps. if not, get back to me. There are other more harsh alternatives.

Can you determine the source of those stains? They look pretty nasty. If the stains are coming from the scupper pipe itself, then consider replacing them with brass.

01-08-2011, 07:49 AM
what is a scupper pipe?when ya tell me what it is I will check. thanks Chuck

01-08-2011, 01:39 PM
There are two holes at the rear of your deck that allow water to drain off the deck out through the transom. These are call scuppers. Usually, the pipes inside the scuppers are plastic or copper. But on some older boats they used galvanized steel or low grade brass. From your picture it looks like those pipes may have been galvanized steel have deteriorated, causeing the stains on your transom. If that is the case, then the pipes can be replaced with copper or a high grade brass.

01-08-2011, 04:20 PM
ok thanks,I am sure your right.........I will replace them what do you suggest using?pvc or copper? oh sorry I seen you told me what to replace it with.copper or high grade brass. is it much of a job? I will do it but just curious what it intells

01-08-2011, 05:09 PM
The first thing to do is get in there and see exactly what you have and the specific source of the rust stain. Then start a new thread on this forum because I'm sure there are some folks that have a lot more experience than I do in replacing those inserts.

There are two ways to replace them. The best repair is to knock out or hone out the old ones and replace them with a high grade brass or copper pipe. If you replace them, you need to be very careful to seal the outside of the pipes very well and completely into the transom, otherwise water will get by them and into the transom and rot it out. Some folks seal them with 2-part epoxy. I've also used 3M 5200 which works very well. The second approach is to thoroughly clean the old scuppers, hone the inside with a brake cylinder hone, seal the metal on the inside, and then insert a tight fitting copper or brass tube. Again, seal the mating services between the old pipe and the new one thoroughly.

After the job is done, you may want to add an anti-reverse flow device to the outside of each scupper. I prefer the ball type as opposed to the rubber flappers.

Look at the following site...


As I said, there are some folks on this forum that are probably far more experienced than I am in doing this repair.

01-08-2011, 07:05 PM
thank you

01-14-2011, 09:29 AM
If the transom is solid thru there (should be), I'd be incline to just remove the metal tube and put a good grade of epoxy back in there to seal the hole. If needed, you can add additional layers to build up the ID of the hole. A touchup with a matching color of marine grade paint and it should never need any more attention.