Accessabiltiy
Steve,I have had a similar problem on my O'day 35. Replacing the sanitation hoses helped a lot. You can check them to see if the odors have permeated the hoses before you decide whether or not this job needs to be tackled. (Also replaced the vent hoses for the holding tank, as they had permeated as well.) In spite of this, there is still a low grade odor that is evident, especially when accessing any storage area that opens into the hold areas underneath the settees and berths. Like some of the other responders have mentioned, there are places where water can accumulate and stand, like under one of the settees where there is no weep hole into the bilge. However, I also believe that there are some area that are not accessible without cutting some fiberglass due to the molded floor upon which the holly teak sole is glued. In my boat, the one area where the odor seems to be worse is in and underneath the mid-ship hanging locker. There are weepholes there, but I don't think they go directly to the bilge. I haven't figured out how to get to it, but ideas include dumping a gallon of bilge cleaner in the bottom of the locker, and hope that it gets to the bilge and/or clean out the offending odor source on the way. The other idea is to use some KO, which works great to eliminate odors when you can spray the surface directly. However, I have my doubts when I don't know where it's going. My last resort will be to use a hole saw and cut a bigger drain in the bottom of the locker in hopes that it will open it up enough to see what happening under there, and maybe allow cleaning and treatment.Sorry I didn't offer a solution. Hope you find one and pass it on if you do.Ed Ryan