You learn all kinds of things when you have a cruising sailboat. You are away from basic services, so you have to be your own electric company, your own water company, your own sewage company, among many other things. Today I am writing about our LEAST favorite utility from that list: sewage disposal.
There is one problem in particular that plagues boats in salt water. Salt water is not compatible with human waste. When you mix the two, a small amount of hard, stony material precipitates. Over time this hard stuff collects on the inside of pipes and tanks, gradually clogging them.
This stuff is called many things by sailors, usually names not printable. But when in polite company, it is usually called “calcium”. Many sailors assume it is calcium carbonate, the material that seashells are made of. It is not. It is a complex mixture of various things, likely mostly calcium oxalate, a primary component of some kinds of kidney stones. The photo on the right is what we found in the hoses in our aft head. Not a disaster–yet. But the diameter of the hose has been reduced by almost 25%, and every narrowing of the hose makes a truly messy clog more likely.
One common myth about this stuff is you can prevent its formation and/or dissolve it away with vinegar. Nope. Doesn’t work. This is one of those things that gets repeated so often people start to believe it. It is told to beginning sailors, and becomes part of what they “know” to be true. “Experts” say it all the time. A simple experiment shows that vinegar has almost no effect at all. After the “Before” picture was taken, we emptied the hoses of all water, and filled them with straight, undiluted vinegar, and left them to soak for six hours, then flushed through with seawater. The result was, as you can see, not worth the trouble. The stuff lining the hose was just as hard, and just as intact as it was before.
The traditional way of cleaning this stuff out is to remove the hoses, take them to the dock, and beat them against a piling until it breaks up into little pebbles and falls out. It is effective, but not exactly a great way to spend your afternoon. It also does not do any good at all for tanks, and piping that you can’t remove.
Trac Ecological Sew Clean to the rescue. While at the Annapolis Boat Show in October we found a product that claims to make this problem go away from a company called Trac Ecological that specialized in this kind of cleaning. I am always skeptical of things that work “like magic,” but given the hassle of the alternative, this stuff looked worth a try. It’s a concentrate that you dilute 5:1, so you don’t need a lot of it.
I am happy to report, it worked, and not just a little, but perfectly. The picture on the right is the same hose after a 6 hour soak in SewClean followed by a saltwater flush. Pretty impressive.
Update: Instead of a long soak, it is much faster if you can recirculate the cleaning solution. The first time we did this I could not figure out a way to do that. Recently, I realized that we can empty the holding tank, close the discharge valve, add the cleaning solution, then extract the cleaning solution from the holding tank deck fitting with our vacuum oil extractor. Empty it back into the toilet. Pump back to the tank. And repeat. Cleaner in a fraction of the time since the cleaning solution is mixing all the time.
Now, there is one thing you have to be careful of. Not all of the hard chips will fully dissolve, especially if you have a really thick layer. It is possible that they can lodge somewhere in your piping and cause a problem. In our case, everything either dissolved or broke up into small enough pieces that it just flushed through. It is best if you can arrange for the cleaning solution to circulate through your system, but there was no way we could figure out to do that, so we had to settle for a simple soak.
We are going to add this to our regular maintenance program and do this soak every 6 months. A gallon of diluted SewClean costs about 8 times as much as a gallon of undiluted white vinegar, but it works 100 times better. The vinegar is staying in the galley–where it belongs.