Metal disk ?

Hello, scraping the hull of my swan 38, I found to starboard, to the birth of the keel rather backward, a metal disk of 10 cm diameter (copper or brass ?). Do you know what it can be used ? Is it-I have to leave this apparent disk or cover it with plastic or paint ? Thank you. (see the pictures)

Dear Cocatrix,

I strongly suggest you leave it in, at least if everything is intact. It is not a disk, it is the famous "bilge drain" or "garboard plug" (or "Pantaenius plug", because if you forget it when launching, you will need to call your insurance).

If it is still functional (i.e., not covered inside, and not welded shut), and once you are on the dry, you can open the center part by turning it anti-clockwise. Then you will have an opening to the deep point of the bilge, so you can spray down the inside of the hull with fresh water, and it will simply run out, taking salt, dirt and small debris with it. When we bought our boat, not knowing this feature, I was slightly worried - after all, it is a submerged opening at the deepest point of the hull. But it is so incredibly useful that I replaced the plug rather than covering it when the threads were worn down some years ago. The part is still available.

Fair wind,

Martin

thank you a lot Martin
I am reassured