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Winterizing water tank... vodka or pink stuff?

Dec 30, 2010
188
Pacific Seacraft Orion27 HP: San Diego, M: Anacortes
I am in the PNW, and yes, we do get freezing temps here from time to time... although not what you folks in the NE tend to get. Just this summer a fellow on the same dock mentioned that yeah, there was some thin ice forming on the top of the marina waters at the lowest temps of winter.

I do keep a small circulating heater/blower going in the equally small boat... all winter... only 70 watts. This does little more than keep the boat fresh.

In the past, I did not bother with winterizing the FW tank and system as frankly I kept it dry due to a failing tank cover. I have now re-epoxied the tank, and installed a new cover... I suppose I could just pump it all dry again.

Or winterize it... the choice being either vodka or the pink stuff. I am trying to figure out the ratio of either to water left in the system.

We just reach freezing... so this is not to keep the system good in sub zero temps for weeks... just to keep it from forming ice in the 6 or so days over the entire winter that it just gets to 32F.

So any ideas folks? (meanwhile, I am going to compare the price of cheap vodka to WM pink stuff)
 
Dec 30, 2010
188
Pacific Seacraft Orion27 HP: San Diego, M: Anacortes
Well, pink stuff is vastly cheaper than vodka... GRIN.
 
Jul 7, 2004
5,922
Hunter 30T Cheney, KS
even if you pump it dry, you want to run antifreeze (your choice) thru the lines and pump. We use the pink stuff full strength until it comes out the galley and head faucets..
 
Jan 11, 2014
4,159
Sabre 362 113 Fair Haven, NY
Some water in the tank is not going to be a big problem. It takes a lot of cold to remove all the heat in the tank and the water below the waterline is probably going to stay at or above the freezing mark.

The part that could cause more trouble is water in the lines and the pump. Since the volume of water in these areas is less, they are more susceptible to freezing. Compared to the tank, the water in the lines and pump will be constrained by the plumbing, leaving little or no room for expansion once it freezes, that's what breaks stuff. In the tank, there will be air space for the water to expand into, provided the tank is not filled to the brim.

I never put antifreeze in the water tanks, too hard to remove it later. The tanks are drained, the line from the manifold (I have 2 tanks) is disconnected and compressed air is blown back through the lines to dry them out. I think pump Propylene Glycol (the pink stuff) through the various facets after draining and bypassing the HW tank.
 
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Jul 7, 2004
5,922
Hunter 30T Cheney, KS
BoatUS just put out a video on it. I can't watch it. YouTube is blocked at work:angry:

 
Jun 11, 2011
1,196
Hunter 41 Lewes
I am in the North East and we definitely have freezing temps. I pump the tanks dry using the water pump, then manually drain the water heater tank, then attach an air compressor with the output set at about 60 PSI to the fresh water connector on the stern and open each faucet one at a time and blow the lines dry. This works well. The air compressor can be attached to the water pump output line if you don't have a dock water connection on the boat. You don't need to buy anything.
 
Dec 30, 2010
188
Pacific Seacraft Orion27 HP: San Diego, M: Anacortes
BoatUS just put out a video on it. I can't watch it. YouTube is blocked at work:angry:

It's pretty darn generic... and doesn't talk about ratios of water to pink stuff...
I would kinda like to keep some water in the tank, as when it is empty, the boat heels and freaks out the marina staff. (somehow they don't see the little note in the "window")
 
Dec 30, 2010
188
Pacific Seacraft Orion27 HP: San Diego, M: Anacortes
It's pretty darn generic... and doesn't talk about ratios of water to pink stuff...
I would kinda like to keep some water in the tank, as when it is empty, the boat heels and freaks out the marina staff. (somehow they don't see the little note in the "window")
Of course the solution to this is to pile stuff on top of the water tank to "simulate" weight in the tank... that might be the solution.
 
Oct 29, 2016
1,402
Hunter 41 DS Port Huron
I pump the tanks dry with the onboard pump then disconnect the PEX connection just down stream of the tanks, plug in a short piece of PEX and stick the other end in a jug of pink and start the pump again this time drawing antifreeze to each outlet.
 
Last edited:
Jul 12, 2011
797
Catalina 36 Bay City, MI
First, @Maine Sail has a great write-up on how to do this properly so you won't find damaged stuff in Spring. Go learn from the expert. https://forums.sailboatowners.com/index.php?threads/fresh-water-system-winterizing.102188/

Second, each boat is different so what works for some guy on the internet may not work for yours. As @dlochner said, the damage will occur first in anything hard (fittings, pumps, etc.) where water has no ability to escape. I can drain my tanks at the manifold, like Dlochner, and never put pink stuff in the tank. I flush with pure propylene glycol from that point through all faucets. Then again, I do not have places between tank and manifold where water can pool, so it's dry all winter. If I had a place with a dip in the lines, it may split the hose there. BTW: I've never heard any responsible sailor still using vodka.
 
Dec 30, 2010
188
Pacific Seacraft Orion27 HP: San Diego, M: Anacortes
First, @Maine Sail has a great write-up on how to do this properly so you won't find damaged stuff in Spring. Go learn from the expert. https://forums.sailboatowners.com/index.php?threads/fresh-water-system-winterizing.102188/

Second, each boat is different so what works for some guy on the internet may not work for yours. As @dlochner said, the damage will occur first in anything hard (fittings, pumps, etc.) where water has no ability to escape. I can drain my tanks at the manifold, like Dlochner, and never put pink stuff in the tank. I flush with pure propylene glycol from that point through all faucets. Then again, I do not have places between tank and manifold where water can pool, so it's dry all winter. If I had a place with a dip in the lines, it may split the hose there. BTW: I've never heard any responsible sailor still using vodka.
I am rather irresponsible. GRIN.

Thanks.
 
Dec 2, 1997
7,393
- - LIttle Rock
If the boat stays in the water, you don't need either one unless the water freezes hard to an inch or more..a skim of ice on the surface isn't enough to matter. 'Cuz boat hulls take their temperature off the water they're sitting in, so everything in the boat that's at or below waterline can't get any colder than the hull. So as long as it doesn't get cold enough to make hard ice, no need to winterize the water tank.

It's a good idea to winterize a sea water toilet though...'cuz the bowl is exposed to the air temperature, and water left in the inlet hose and the inlet fitting on the back of the bowl can freeze hard enough to crack the bowl. I lived in Atlanta when I was still in business...and even there, we could get teens-single digit cold spells that lasted several days. And every spring I'd get calls from several people who needed a new toilet bowl.

--Peggie
 
Mar 16, 2010
5,943
Beneteau 411 Oceanis Annapolis
I strongly advise you to NOT put antifreeze OR alcohol in the water tanks. AF is bacteria food, you will start a colony, alcohol eats up gaskets, pump membranes and valve seats. Drain the tank, pull the water supply line off at the manifold or pump and pull PG AF through your potable water system. Bypass your HW heater. Leave the tank supply lines open all winter. Get a refractometer on-line and test your AF for strength. Drain your HW heater and leave it open.

Go here and read up. Then donate to his site, he just saved you a lot of money.
 
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Jun 14, 2010
925
Quorning Dragonfly 1200 home
If the boat stays in the water, you don't need either one unless the water freezes hard to an inch or more..a skim of ice on the surface isn't enough to matter. 'Cuz boat hulls take their temperature off the water they're sitting in, so everything in the boat that's at or below waterline can't get any colder than the hull. So as long as it doesn't get cold enough to make hard ice, no need to winterize the water tank.

It's a good idea to winterize a sea water toilet though...'cuz the bowl is exposed to the air temperature, and water left in the inlet hose and the inlet fitting on the back of the bowl can freeze hard enough to crack the bowl. I lived in Atlanta when I was still in business...and even there, we could get teens-single digit cold spells that lasted several days. And every spring I'd get calls from several people who needed a new toilet bowl.

--Peggie
Peggie, I have the greatest respect and appreciation for the countless pearls of wisdom you share online and have purchased (and read) your book. However, in this case I disagree that the interior of the boat would be sufficiently moderated by the sea water temperature to avoid freezing air temps which can freeze interior freshwater hoses and fittings.
It only takes hours in the high 20’s to cause freeze damage.
 
Jun 14, 2010
925
Quorning Dragonfly 1200 home
Gene, also after you winterize, leave all fresh water valves open so any residual water doesn’t crack the valve fitting if it freezes and expands.
 
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Dec 2, 1997
7,393
- - LIttle Rock
However, in this case I disagree that the interior of the boat would be sufficiently moderated by the sea water temperature to avoid freezing air temps which can freeze interior freshwater hoses and fittings.
I appreciate your comments...but if you read my post again, you'll see that I did not say that temperature in the entire interior boat would be moderated by the sea water temp...that I specifically said anything in the boat below the waterline would be ...and that I specifically recommended winterizing the toilet plumbing because it can have water trapped it and IS exposed to air temps.

Freezing temps alone aren't likely to damage anything. Water expands 10% when it freezes, so any pipes full of water that are exposed to freezing air can be at risk. But it's the water pump that keeps water in the pipes...when it's turned off the water drains to lowest level in the plumbing, almost all of which is below the waterline.

Remember, we're not talking about protecting a boat on the hard for 6 months of winter in Minnesota, just boats in water that doesn't freeze during a few days of freezing weather.
--Peggie
 
Jun 14, 2010
925
Quorning Dragonfly 1200 home
When my pressure pump is off the hoses don’t drain back to the tank. The water stays in the hoses and fittings unless I were to open faucets and disconnect the pump. Even then, water would remain in low points of hoses and fittings unless it was blown out.

PS. @uncledom I think 60psi is more pressure than needed, and likely exceeds the normal range of your water pump pressure switch. (The air pump I use is high volume low pressure intended for dinghy inflation and maxes out at around 15psi. I find it sufficient for blowing out the water hoses.)