Well, after 9 years the boat was beginning to gain a heady aroma. The head hoses were permeated and an inquiring nose could tell. So, changed out all hoses in the aft (most used) head .
Look at the picture of the hose from the y valve to the holding tank. It is the one that holds stuff due to the holding tank being high.
It weighed significantly more than the others upon removal. Now i see why. Probably would have clogged shut during some dark and stormy night, or at the most beautiful anchorage. Only about a half to three quarter inch opening remained.
Thanks for the photo. Our boat is also 9 years old but so far so good, no smells. My question for you is;
Are you using seawater or, on board fresh-water ( from tank) for flushing?
We installed a Jabsco fresh water flush system on our boat upon delivery and whenever I change joker valves I look/check hoses, so far, as far as I can see, they look clear and flush time seems consistent. We were lead to believe the smelling/blocking of lines is cause by deceased microbiological sea critter buildup in lines, not human waste. I have not checked the line from the Y valve to date. Additionally, if its human waste block up I would think clearing the lines might be a possibility since human waste should break up/dissolve fairly easily?
James, we use saltwater when offshore. Otherwise we use a freshwater flush. The design is such that whatever is in the line sits between the top of the holding tank and the joker valve. Over time, stuff builds up. Amazed at what a human can produce! Calcified urine, etc.
Sam, wow that's some serious blockage. Like James we too flush with fresh water. And like James haven't had any issues with hose blockage (that we know of) or odor. Actually we find our biggest source of odor in the heads come from the sink/shower sump. We flush them on a regular basis or when they begin to stink. It's amazing the gunk that sticks to the inside of that drain hose and the odor it creates.