[Putershark]

I had the same problem with my old 210. but I have a fix for you.... Take out that drain cover and right at the lowest points in the cover (where your fingers would rest when you would be twisting it off) I drilled all the way though the cover with a drill bit about the size of a large pencil

By doing it here, it creates a slight siphon effect, and will pull out most of the water that gets in there into the bilge to get pumped overboard... Simple fix even if you never find the reason why it gets there in the first place