Bottom paint on rubber

I finally got around to painting the bottom. It's futile in SW Fl to wait on a cool day! I get to the boat at the crack of dawn and I'm good until noon. (the latest)

I have a question for those DYI dudes out there. My scuppers were coated with growth. I scrapped them off and I will go back with a scuffy pad to get them cleaner. Why not paint the scuppers? Is it a no=no to paint a rubber surface?

While it's out, I want to do whatever I can that can't be done in the water. It would be very simple to throw a few coats of paint on those barnacle coated scuppers.

Sure paint it, why not? People paint everything underwater with bottom paint, except anodes. I have 2 hard rubber underwater exhaust extensions painted with antifoul. These are real old, from the late 1960's and are in good condition.

The purpose is to send exhaust gasses underwater, make less exhaust smell.
They do modify the exhaust sound, although I dont know how many have any such thing anymore.
I suppose they also help a little when backing up, less water forced up the exhaust.
The bottom edge is right at level with boat bottom, so they can not catch on anything in the water.

They look like they are in great condition. The 1960's, WOW. Almost as old as me!
Thanks. I'm gonna paint them. The paint will either stick or not.

If you’ve got scuppers below the waterline, you’ve got problems bigger than paint!

Scuppers is probably the wrong word. They are exhaust scuppers and prevent water from going the wrong way up the exhaust.

Molly said:

Scuppers is probably the wrong word. They are exhaust scuppers and prevent water from going the wrong way up the exhaust.

Click to expand...

If you mean those rubber flappers .... they are not "scuppers". "Scuppers" are a different thing altogether.

Better questions = better answers

Scuppers drain water off the deck. Flappers prevent backflow in exhaust. If they are rubber then petro based paint might soften the rubber. Safest to use water based transducer paint. (But if I had a half empty can of Tri 33 spray paint I'd probably use it.)
They are inexpensive to replace if externally mounted.