A few places to look
I had a nasty leak in my aft cabin/stern lockers. I found three places where it was coming in. The hatch above the steering quadrant (directly behind the wheel). The port in the aft cabin. And the tricky one, the scuppers were leaking. But they would only start to drip after being soaked for a long period of time. It turns out that the place where the tube of the scuppers meets the bottom of the cockpit there was a bunch of small cracks. It took the water a good twenty minutes to make its way down thru the cracks and finally leak out the bottom of the scupper assembly. I brushed on two coats of epoxy and Bingo, dry aft cabin. Good luck