f79r - something written under water ???

[oshfdk]

You have to remember that these are hard marks under paint or paint that would leave a mark that used paint for intention there is word there and that word is Konr.

I think it's more likely there is some drawing there and not a word. However, could be a painting instruction too, but I don't think it's possible to read any shapes there except the sideways ^ (which is the r in your interpretation)