Ok, here is the thread I remember, it has some pictures that are helpful, and is worth reading in its entirety:
http://forums.sailboatowners.com/in...ter-31-persistent-leak-near-fuel-tank.181234/
Take a look at the picture in post #1 of that thread. (I suggest opening it in another browser window, so you can bounce back and forth.) It shows the "trim piece" I am talking about, running fore and aft along the quarterberth ceiling, covering up the run of the steering cables. I don't have this piece in my boat. In other words, my quarterberth ceiling is flat, all the way from the port hull to the dividing wall amidships. Unfortunately, I do have the screwholes left from the attachment points of that trim piece.
Then take a look at the nicely labeled last picture in post #7. Glenn has removed the trim piece, and you can see the steering cable access point. If you expose this access point, you can put your fingers on the top side of the quarterberth ceiling over a limited area. The fiberglass is rough though, be careful if you do this.
Yes, I did follow that post and I checked out all those possibilities but did not find anything. I cleaned that water out of the tank today and it turned out not to be as much as I thought, maybe a bit less than a litre. I am wondering if perhaps it was just the water that was in the suction hose which I transferred from a five gallon container in the aft laz to the suction fitting on the tank. I did not cut the hose down to size, just left the excess in that vacant space inboard of the tank so there could have been a fair bit in the hose. I spread newspaper all around the quarterberth today so we'll see what happens next time it rains. On my boat, when you get down into the stbd laz and try to look between the cockpit sole and the liner there is virtually no space at all. I put the garden hose in the cockpit for a half hour and no leak appeared anyplace. I do think I may have a leak at the stbd toerail around the stbd laz but that one can wait as it won't hurt anything.
One more thing. I can see a fair bit of the top side of the quarterberth ceiling from inside the starboard laz, below the cockpit floor. Put your back to the starboard hull, and look across the boat to the port side. The "airspace" we've been talking about is widest on my boat just abeam the forward edge of the fuel tank. A flashlight will let you see all the way across the quarterberth ceiling to the scupper, where it penetrates both the cockpit sole and the ceiling of the berth. I sat and watched that dusty space for about 10 minutes while the admiral put a hose in the cockpit. Sure enough, a line of water began flowing slowly across the ceiling, easily visible because it was dark against the lighter fiberglass. It confirmed my scupper was the issue. The water accumulates at the lowest point, which for me is just above the fuel tank. When enough water accumulates, it spills over the edge and goes from there. Hope this helps.