Looking for old post on mast step water

Hi folks,

I keep getting 997 or 998 returns when I search for
"mast step" channel water bilge (and anything else I try but "monkey" then I get 11, so search is working).

I know there is a post talking about creating a channel for the water that gathers on top of the mast step into the bilge, but I've looked through pages and pages of these returns without finding it. Wouldn't want to grind a channel on my E38 and then have the mast fall through the hull...

Thanks and my apologies for being a poor searcher.
Terri