bilge bile
When I removed the sole of my hunter 28.5, I found plenty of fungi-based horror festering between the stringers aft of the bilge. There are weep holes in each stringer up to but NOT including the engine tray area. However, these weep holes are about 1/4" or more off the hull, so water gets trapped in between the stringers and then you have your black yucky stinky water.The sources for the black water are as the other posters have said - the ice box and the shower drain can contribute especially if the original shower hose is still under there - it probably has developed cracks. Now theoretically, the engine tray water should NOT find it's way into the forward stringers or the bilge because it may contain fuel, oil or both - and pumping that stuff out into the sea is a major no-no. Some water can get into the stringers from where the battery cables run through the stringer to the starter.Also, the fresh water supply to the galley sink runs through one of these stringers and in my case, I had a fresh water tubing leak inside the stringer that contributed to the water accumulating in this area.When I replaced the sole - I cleaned the stringers aft of the bilge as best I could. I also opened the weep holes so they met the hull to maximize the water flow into the bilge. I replaced the shower drain hose, but I did not plumb the ice box. I have had very little water in these rear stringers even though I use the ice box - presumably because I opened the weep holes to meet the hull, allowing for more complete run-off into the bilge. Removing the sole is a ton of work, as you have to disassemble the galley to do this. I agree with the other post that the less labor instensive solution is to add a sole hatch so you can clean/flush regularly. Note there is no access to the inside of the stringers other than the weep holes, so you will never get the inside of the stringers completely goo free.Good luck....PS - to replace the galley plumbing, you do not have to remove the sole since the run through the stringer and are not exposed under the sole.....