We have a steadily increasing odor from one of our holding tanks, even though they are both being treated the same, and we try to use the heads equally. After a lot of research, we came to the conclusion that the tank vent is plugged. As the skipper previously wrote, heads, head repairs and the attendant accoutrements are his responsibility, not least because Jack’s sense of smell is marginal at best and I can pick off a piece of fruit one day beyond its sell-by date at fifty paces.
He began by disconnecting the vent hose from under the sink and probing it with a plumber’s snake. Yep. Clogged. There shouldn’t be anything but air in a vent hose, so having waste in it explains the odor, not to mention restricted air flow for the enzymes we use to treat the tanks to be effective.
I read on a blog that sending a stream of water from the outside of the vent can clear the clog with the added benefit that it sends the offending material into the tank and not into my nice clean bilge or anywhere else where I might smell it in perpetuity. The only problem is that our vent is under the boat, a space that’s too low for the dinghy to fit. Five Below to the rescue, where we bought a blow-up pool raft for $2. After hours of trying to blow it up, Jack announced that it wasn’t worth the two bucks.
Finally, with the raft somewhat inflated, we discussed how this would work. Since there’s nothing to hold onto under the boat and there’s always a bit of a current running here in the lake, Jack wanted to first rig a line bow to stern so he could pull himself back and forth and hold himself steady while squirting the vent. I tied a line to the bow, Jack plunged into the water and paddled underneath, I handed him the line and he paddled back to the stern, where I took the line and tied it off.
That done, I handed Jack the hose and he pulled himself back to the vent and tried to clear the clog.
Unfortunately, the vent is so plugged that when Jack took the hose away from the vent all the water he just squirted came right back on him. So mission not accomplished.
What this tells us is that the clog is right at the fitting on top of the holding tank, and that means disconnecting the hose from there, a process that will surely end up in a smelly mess inside the boat.
Not looking forward to that.
Jack looks really thrilled !
Thanks for sharing!!
Sounds like replacing the hose might be the easiest option, if all of it is accessible – or even replacing the upper portion, with a connector and hose clamps, to the existing hose. Use the white sanitation hose that is impermeable to prevent odors.