Dave,
I think I was the one who started the thread you're looking for, I think it was about 2 or 3 years ago, but I don't remember the title.
Just to review, I had three valleys (not just one) which were trapping water, the big one kh3412 is talking about, a smaller one just aft of it, and a larger but shallow one under the aft berth. My goal was to eliminate all standing water and create a smooth runway for any water to run to the bilge. I don't know what kh3412 found, but the valleys in my boat had some pretty nasty stuff in them along with the standing water.
What I did to remedy the situation was after thoroughly cleaning them out I shaped teak blocks to fill the voids then poured West Systems epoxy over them to seal a smooth the area. It worked very well and now there's no where for water to become trapped.
kh3412,
While I think this is a worthwhile thing to do, I'm not sure it rises to the level of a critical update. Maybe if you live in an area that freezes, but mine was like that for decades before I got around to fixing it.