Leaking holding tank: What would you do?

[Fiddlerman]

Originally Posted by Ocean Girl

Now that's one way to deal with a leaky holding tank.

That is exactly what I was thinking.

[Roy M]

First, you have my sympathy. I've been there, on someone else's boat, and it was awful. Second, It is do-able, you just have to be brave and fearless.

Anything short of complete removal is going to bite you someday, only prolonging the number of times this issue will hurt. So, you have to remove the tank and replace it the way it should have been built in the first place. The key word here is removeable. Murphy's Law has not been, nor ever will be eliminated from the other Laws of Nature.

It's only a pain, it's not about total destruction and perpetual chaos. Remove everything on top of the tank, and, if necessary, any vertical elements. If you do it somewhat neatly, you will be able to cover the damage with trim and no one but you will have any idea of what happened. Then, wash the interior of the tank with detergent, bleach and lots of rinsings. It's still going to be nasty, but it will not be as bad as it could be. Then, chop off the elbow and haul out the tank. Now, let the compartment dry out so you can examine every part of the empty space for rot or other issues. Fix those. Now that the hose is clear, this is the best time to install another one, so do what needs to be done to track the line to its deck fitting and to the macerator pump and overboard discharge. Make sure the macerator pump is functioning perfectly and is accessible for future replacement. These pumps often sit idle for so long that the uric acid crystals and other waste seize up the impeller like concrete. You should "exercise" the pump monthly, even for a couple seconds. Consider replacing the pump now while you are overhauling everything. It will never be cleaner than it is at this point. It's only money, and life should be more than repairing sewage systems.

Next step, a new tank. This time you get to learn from the mistakes of others. The simplest and cheapest solution is to make the tank yourself out of plywood, sealed in epoxy resin, with standard fittings for through hulls. Make the tank slightly smaller at the end where the input and exhaust hoses, and the vent hose, are attached. If you don't have the three hoses at the same end, try to make it happen at this stage. Since you can make the tank any size or shape needed, do so, because there will never be a better time. Most folks never get a chance to make their boats (or sometimes, their lives) better, like this. You should consider this awful endeavor as a blessing in disguise. Future owners of your boat will never know what a great person you are.

Make sure that the top of the compartment is completely removable and quick to open for inspection. You can even build in a cleanout port if you are really insane. I am, and I did.

Lastly, this will be the only time you can make the decision to go with an aerobic digester holding tank. It requires TWO vent hoses, each 1 1/2' in diameter, located at the top of each end of the tank, which then lead to through hulls on each side of the hull. They capture the breeze and exhaust the gases out of the holding tank, allowing you to charge the system with aerobic bacteria which consume the poop and don't smell anywhere as bad as what most folks have right now. It's a fair amount of work, and it's not for every boat, but it should be considered, at least.

If you can relocate the tank to a position above the waterline, that's even better because it allows you to have a self-draining tank without the need for a macerator pump. Here's a picture of my system.

Good luck! The reason I can be so smug is that I built my own boat from scratch, while working on building boats for others. I learned what problems they had, and built so that I could avoid the same problems. So, EVERYTHING in my boat is removable, and has inspection ports or access so that I can put an eyeball and a hand, with the necessary tool room to swing it. I make money working on other people's boats, not my own.

[IdoraKeeper]

Originally Posted by Bash

There's no way your going to solve anything without taking the v-berth apart first. Do it. At that point, it will occur to you that it's just as easy to remove and replace the entire system as it is to find the leak, at which point you'll probably remove and replace the entire system anyway.

When your staggering up the dock in filthy poo covered coveralls wearing a respirator and goggles and big rubber gloves....everyone will run in terror/fear and loathing....you only want to do this once. Bash is utterly correct. Rip it out, rip it all out. Fix it once and for all.

[Sailmonkey]

Did either of you look at the whole thread?

[Fiddlerman]

LOL, It's all my fault for replying to an old thread.

However, I love Roy's tank. Having the pumpout completely on the bottom like that, along with the V shape, is fantastic. Also, so easy for him to inspect. I never thought of making my own tank that way but my time is limited and the plastic tanks are so inexpensive today.
One thing I would have done differently is to invest in better hose though.
I know that it is super pricy but much cheaper if you get a 50' roll. Perhaps the smell permeates through the epoxy too??? No idea.
Roy, is that really a 1-1/2" vent? Wonder what it smells like around the outside of the vent?

[Roy M]

The white 1 1/2" hose is pricey, but you can use it in a variety of places, so I would consider the 50' roll. The epoxy does NOT pass any odors. It's so impermeable that I also used it to build my fuel tank (and several more for my customers). For insurance purposes, it is defined as a cellulose-core, epoxy-graphite sheath composite.

Yes, those are both 1 1/2" hoses, criss-crossing to through hulls port and starboard. It conducts plent of fresh air for those greedy little bacteria that compose the "K.O." holding tank additive made by Raritan. I learned about this system several years ago from Peggie Hall, who is a regular contributor to Cruisers Forum. Most tanks use a mix of formaldehyde, colorant and perfume to disguise that unique scent we call dead poop in preservative. Peggie's system uses a completely different approach, basically the same used in modern septic systems. The poop is populated with anaerobic bacteria from your gut (that means they live without the need for oxygen). When dumped into a soup of aerobic bacteria, needing oxygen to flourish, the bad bacteria are eaten up by the good ones. In the process, the gases produced are much different in smell, more earthy, like a garden or compost heap. In fact, it's the same process that occurs in your vegetable patch. It works! Regular holding tanks always stink.

In places where you can dump your holding tank waste, what comes out is not the poisonous brew that formaldehyde creates, rather, the product of ongoing aerobic decomposition, the same as you find in the ocean. Mine is the only tank that doesn't stink on my dock (and probably the rest of San Diego Bay).

[Fiddlerman]

Great information. Wish I had read this before doing all the work on my new holding tank. A month ago I changed the diesel tank as well.
Thanks Roy.

[Roy M]

Sorry, Fiddlerman. For the future, though, it's really cool to work with epoxy/ply for tankage. I use Baltic birch ply, even though the glue may not be rated for exterior use. Once sealed with epoxy, it is tough and has a beautiful finish. I add white pigment to most stuff, but also use black for the diesel tank. You can make baffles wherever you want them, add inspection/cleaning ports as large as needed, install new fittings whenever you want, and pull the entire tank out when you need to. Here are some pics showing the exterior and interior, as well as the installation.

At the time of the photos, the tank was fifteen years old. I drilled through the top to install an electric fuel level indicator, and the core plywood smelled like "Tinker Toys", an indication of how well it resisted infiltration of diesel odors.

[Fiddlerman]

Very nice. What about for your water tank? That is my next project.

[Roy M]

For water tanks, go polyethylene, period. Remember, water is constantly absorbing any chemicals in contact. Polyethylene is now considered to be the safest material. I will be converting all of my plumbing to poly pipe tubing, as well. Consider using two smaller tanks, joined by a common tube at the bottom, with a shutoff valve. It serves as a baffle, since there are no poly tanks with sufficient baffles inside to soften the "crash" of all that water in a seaway. It also allows you to separate your tanks in case of leakage or fouling. And best, poly tanks aren't that expensive.