Need to winterize but holding tank half full

[Rohan]

Short version:

I have a raw water flushing head and a 35 gallon holding tank.

I need to winterize the boat, but due to boat repairs that took longer than expected, I missed the season cutoff to do a pump out, and my holding tank is nearly half full. The nearest option to pump out is a long way away. I really don't want to do that, and it's far enough that if I go there, I'll probably have to use the head on the way back.

So what to do? I guess I'll pump some antifreeze through the head like usual, but then dump a gallon of antifreeze directly into the waste tank. Kind of gross, but it should be good. Does anyone foresee problems with this?

Possibly relevant - I keep my boat on the Potomac, where the water is brackish, but nearly fresh water. It's rare for us to get a prolonged hard freeze that could cause damage, but it does happen once every few years.

And no, dumping the waste in the river is just not an option.

[rslifkin]

If you want to get enough antifreeze concentration in the holding tank to do anything useful, you'll need to get some pretty strong antifreeze (at least the -100* stuff) and just about fill the tank. Unfortunately, you really, really need to find a way to get that tank emptied before winter layup. Letting it sit half full isn't going to do you any favors in terms of forming sludge in the bottom of the tank.

[leecea]

I saw this: https://www.westmarine.com/star-brit...-14823355.html

If you get a pump out and have to use the head on the way back, that would seem better than a half full tank.

In Rock Hall there is a company that will come to the boat with a portable pump out. It's expensive but if such a thing is available in your area it could be an option.

Sorry you got stuck like this!

[MGRodems]

I had a similar problem last winter in the Norther Chsapeake. I put a gallon of the pink stuff into the head and flushed it into the tank. Some was also added into the tank deck fill. Smaller tank, but it was almost full. Everything was fine in the spring when I pumped out.

[Mike OReilly]

Couple of thoughts:

• Given your climate, latitude, and in-water location, it's unlikely your tank will experience a hard freeze. Unlikely -- but not impossible. So... how lucky are you feeling? If you can get any heat into the boat, even periodically, you would lower the risk significantly.


• Adding a lot of antifreeze is a good idea, but I wouldn't fill it completely. Ice does damage when it has nowhere to expand. Leaving expansion space is a good idea, but make sure your vent is clear and working. I'd find a way to leave the deck empty cap open (without exposing it to water ingress). If you have an access hatch, I'd open that as well. And rslifkin's suggestion is a good one: use the most concentrated antifreeze you can find.

• While this is unpleasant, it's not hard to pump your tank out yourself. Any decent pump will do the trick, although you'll likely never want to use it for anything else afterwards . Pump it out into jerry cans or olive barrel -- as long as it is solid and sealable. Then carry it to a sewage disposal site.

[SailingHarmonie]

Don't forget that there is water trapped inside the closed valve under the tank. If you don't get it emptied, you WELL have problems if it freezes...

[Rohan]

Originally Posted by SailingHarmonie

Don't forget that there is water trapped inside the closed valve under the tank. If you don't get it emptied, you WELL have problems if it freezes...

That's a good point. If I mascerate it, it should mix it around enough that some antifreeze will get down there too. Here's hoping.

[S/V Illusion]

Originally Posted by SailingHarmonie

Don't forget that there is water trapped inside the closed valve under the tank. If you don't get it emptied, you WELL have problems if it freezes...

The above is the bigger problem. A half full tank has room for expansion of its content should it freeze. The liquid in the hoses, fittings and macerated does not.

The problem will be with the latter components and no amount of “pink stuff” will mitigate that. The pink antifreeze is useless when mixed with water. And running a macerated to a closed thruhull won’t mix anything anyway; it will just make noise and give a false sense of accomplishing something.

As a last resort, pump out the holding tank if only to evacuate the plumbing system regardless of how nasty it might seem or you’ll have a more nasty problem later.

[peghall]

Just putting antifreeze down the toilet into the tank doesn't protect the toilet pump and bowl...we used to replace several toilet bowls every spring that had cracked because there was water in the channel in the rim. To do it right, disconnect the toilet intake line from the thru-hull (close the seacock first!!!) and stick it into a jug of antifreeze. Pump the entire jug full all the way into the tank.


As for your half full tank...freezing conditions aren't what causes damage. Liquids expand about 10% when they freeze, so as long as there's plenty of room for the contents to expand, a couple of gallons of antifreeze should be enough to prevent any damage.


--Peggie

[5BTM]

Call a Port-A-Potty business in your area, maybe they can help.

My club has a portable pumpout setup as well

[Kettlewell]

Pumpout boat? At least in New England just about every decent-sized harbor has a pumpout boat sometimes run by the harbormaster. Or, how about a short trip to someplace like Annapolis that may have a functioning marina dock with pumpout? There are portable pumpout systems, and I don't see why you couldn't rig up a bilge pump and hose to suck out the stuff via your usual pumpout port.

[Rohan]

Originally Posted by Kettlewell

Pumpout boat? At least in New England just about every decent-sized harbor has a pumpout boat sometimes run by the harbormaster. Or, how about a short trip to someplace like Annapolis that may have a functioning marina dock with pumpout? There are portable pumpout systems, and I don't see why you couldn't rig up a bilge pump and hose to suck out the stuff via your usual pumpout port.

The nearest place I could go for a pumpout is six hours away - there and back a 12 hour trip just to pump out my waste tank? Not a fun thought.

[rwidman]

When I had a trailer boat with a head and holding tank, I rigged up a standard macerator pump (the threads fit the deck fill on the boat), a cable with a cigar lighter plug on the end, and a hose so I could do pumpouts at home.

You could do this and pump into a tank large bucket, etc. I actually plumbed into my house sewer system so I could just stick the hose into a pipe, plug it in and watch the poop go away.

[Tedd]

Originally Posted by rwidman

...so I could do pumpouts at home.

That's a fantastic idea!

Are you on any of the trailer sailer forums? I'll bet people there would love to read about your system.

[Goodxcharly]

1/2 full is 17.5 gallons. I would purchase or borrow 4 5 gallon Jerry cans and pump it out. Easy fix.
I wouldn’t leave it through the winter as the smell will leech through the lines.