Is there a way to identify the manufacturer of a plastic tank, or more specifically what the tank is made of? I just removed the holding tank from the v-berth of our 1983 Oday 34, and I am here to tell you that the tank itself stinks. I believe it is the original tank fitted when the boat was new, and it has a capacity of about 12 gallons. I cannot find any markings anywhere on the tank. Some case history, - we bought the boat about this time last year, and over the course of the winter, I made several trips to where the boat was to prepare it to sail to our home port. One of the things we did was replace ALL the hoses for the waste system, including vents, as well as the head itself. The boat had a fairly noticeable head odor inside. After bringing the boat home, this spring I ordered a large quantity of KO and removed all the cushions and their covers from the boat, spraying the covers and the foam, leaving it all outside for several days of sunny weather per Peggie's recommendation. I also sprayed the entire bilge area, all the way to the front of the boat - including the entire underside of the v-berth area. I also sprayed all the fabric lining the inside of the hull, and aired the boat for several days. Over the course of the summer, I have cleaned the bilge (which is never really dirty, but does get some water when it rains) a couple of times with Simple Green, and removed any standing water. The existing holding tank had a vent fitting at the front and at the rear, but they both came together at a T fitting which exited the starboard side up under the rub rail. After buying Peggie's book, I learned this is not ideal since it was more than 45 degrees inclined from the tank. I removed the T fitting, and vented the front of the tank to a new vent under the rub rail near the bow - again, there was no way to avoid the incline, but with two separate vents, one facing forward and the other facing rearward, and since we are on a mooring always facing the wind, I hoped that would be sufficient to keep air circulating through the tank. While all these steps improved the situation, the boat continued to have a faint odor. The boat is now on the hard for winter, and since we have had some mild weather, I have been working on a few projects. Since the smell is always most prominent under the v-berth, I decided yesterday to remove the tank, on the chance that there was a small leak underneath, perhaps keeping the wood platform it sits on wet. In the process of removing the tank, which only had a gallon or so of antifreeze and a small amount of sewage that the pumpout did not remove, I spilled perhaps a cup or so of the vile contents into the bilge. I brought the tank home, and flushed it out several times in the basement sink, so that there was nothing left inside. Today, I visited the tank again in our basement (which is now filled with malodorous air). I applied the sniff test to the tank, and I can say unequivocally that the plastic itself stinks. The top, bottom and sides all smell like sewage, and it is definitely not just coming from the openings in the tank, it is the tank itself. I have always been told that plastic tanks cannot become permeated, but that appears to me to be exactly what has happened in this case. Upon visiting the boat today, I was greeted with the smell of KO, but no head odor, in fact, even the area under the v-berth has no head odor whatsoever. I should also mention that I found NO indications of ANY leaks around the tank, or any of the hoses. My question at this point is, are there perhaps different types of plastic tanks, some that are permeable, and some that are not? I plan on ordering a new Ronco tank, and I trust I won't have the same problem, at least not soon enough that I care, but in looking through their catalogue, I am wondering what the difference in the marine and rv tanks are? Also, what is the difference in their holding tanks vs water tanks? I have called them several times in the last couple days, but have not been able to get through while they are open. Lastly, what is the best solution when you cannot get a horizontal vent?? Even with my vents located up at the rubrail we managed to fill the tank with lakewater while running close hauled into a moderate chop for a couple of hours one time. Thanks, Scott Fuller O34 Dawn Treader Wauwatosa, WI
