Winterizing the water system

May 22, 2017
42
Catalina 310 Lake Carlyle
My first forum question. Boat owners at my lake winterize their water system by pouring about 4 gallons of antifreeze into the water tank after emptying out the water. In spring time they pump out the antifreeze and then fill the tank 2 or 3 times before the final fill.
Sail magazine a few months ago said there is a smart way to do it by only filling the lines from the water pressure pump out to the faucets then no need to do the 3 or 4 tank fills. I sent the editor an email asking if he could explain how to do this but no response.
Maybe someone on the forum knows the smart way and maybe there is no smart way in cold winter areas.
Frank Hines
Lake Carlyle, L.
 
Mar 29, 2011
169
Beneteau 361 Charlotte,Vt
After draining the water tanks. I disconnect the hose from the tank. Stick the hose into a bottle of anti-freeze and turn on the water pump and each faucet until it comes out pink. I also put a by-pass on the hot water tank, and drain the water from the tank. So no anti-freeze goes into the tank. I winterize the engine, water system with about four gallons of antifreeze. The engin is normal winterized while the boat is still in the water, so I can run the engine to get it hot.
 
Aug 13, 2012
533
Catalina 270 Ottawa
what @mcrow33 said. if you want to be extra particular, blow the lines after pushing AF through the lines with compressed air.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
If you open the bilge and look on the starboard side you will find the vinyl water line that goes from the tank to the pump. Cut the line here and install a plastic or brass tee with a valve on the end pointing into the bilge. In the future all you will have to do is open the valve and it will drain the water from the tank into the bilge. We use this to clean the bilge as well.

For the pump and the lines after the pump, we installed this kit to winterize this section. You simply turn the valve to pickup from the hose and then put the hose in a gallon jug of antifreeze and open up the hot and cold side of each faucet (don't forget the swim shower) until you see solid pink come out.

For the water heater we installed this kit to bypass the heater. Once the kit is installed you simply turn the valve to the bypass position, open the heater drain and the pressure relief valve and the heater drains completely. Obviously do this before you pump the system full of antifreeze.

With the above system I could winterize the fresh water with a gallon of antifreeze. I would test the pink water flow with a refractometer. Test the new antifreeze and then test what comes out the faucet (or your engine) and keep pumping antifreeze until it matches the first test.

For the blackwater system, we would pump 2 gallons of antifreeze into the head and then discharge through the masserator pump. I didn't want to test that one. We would fill the tank with fresh water and pump it out several times first.

For the engine, we installed a bronze three way valve on the influent side of the sea strainer. I have a six foot section of hose connected to the three way valve. I can put the hose in a bucket and flush the engine with fresh water and fill it with antifreeze. It can also work as an emergency bilge pump.

Good luck and Fair winds.
 
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Likes: BC Bernie
Dec 2, 1997
8,708
- - LIttle Rock
Or...don't use antifreeze at all. It's not freezing temps that damages pipes and tanks...water expands 10% when it freezes. When it expands more than the available space can hold, the pressure is what cracks the pipe. So you can avoid using antifreeze if you can use a compressor to blow all the air out of the plumbing. That may require installing some quick connects to let any water left in low spots to drain. No water left in the plumbing, no freeze damage.

As the article at the link Rob posted says, never put antifreeze in a water heater...you'll never be able to get it all out. Instead, drain it via the petcock at the bottom of the tank and bypass it. Marine stores sell kits to do that.

In the spring, all you need to do is recommission your fresh water system. You'll find the instructions for doing that in the archives here if you search for "recommission fresh water system"...and also in my books along with a lot more useful information (see link in my signature below).
 
Jan 7, 2011
4,723
Oday 322 East Chicago, IN
On my Hunter 280, the water system was pretty basic, but did include a water heater. After draining the heater and water tanks, I would remove the inlet and outlet hoses on the water heater and used a short nipple to connect the 2 hose ends. This effectively and simply bypasses the water heater.
Then remove the water hose (outlet) from the water tank, and stick the end of the hose in a gallon of pink antifreeze. Turn on each faucet, hot and cold sides until pink flows. Be sure to do every faucet. This should do the trick for the potable water system.

On my current boat, the PO put a few valves and extra pipes on the water heater, so I can then 3 valves to bypass the water heater. Then I follow the process above to winterize.

In the spring, I fill the water tanks and add some bleach and let the tanks sit for a week.
Drain by opening all faucets (hot and cold), fill, drain again, and fill. Water should be clean and bleach free. Reconnect waterheater and then open hot water taps to purge air from water heater and lines. after that, you can turn on water heater electric heating element.

Draining twice sounds like a lot, but I have 2) 30 gallon tanks on my O'Day 322 and did them in a few hours.

Greg
 
Dec 2, 1997
8,708
- - LIttle Rock
For the blackwater system, we would pump 2 gallons of antifreeze into the head and then discharge through the masserator pump. I didn't want to test that one. We would fill the tank with fresh water and pump it out several times first.
WINTERIZING THE SANITATION SYSTEM

HOLDING TANK
1. Pump holding tank out, then rinse thoroughly as follows: put a few gallons of water into the tank via the deck pumpout fitting...'cuz that sends the water into the tank at the bottom to stir up any sludge and hold it in suspension so it can be pumped out...pump that out. Repeat...repeat...till you're pumping out clean water. Now add a few gallons of water one more time and this time run it through the overboard discharge pump to rinse it out. (You might want to do this away from the dock in case someone watching doesn't realize you're only discharging clean water and has a conniption fit about it).

TOILET
2. If your toilet uses onboard pressurized water, all you need to do is put a gallon of antifreeze into the bowl and flush it into the tank...winterizing the fresh water system took care of the rest.

Sea water toilet: Just pouring antifreeze into the bowl and flushing it through won't protect the pump or the channel in the rim of the bowl....To remove water and run antifreeze through the whole system, close toilet intake through-hull, disconnect inlet hose and stick it in a gallon of non-toxic ("the pink stuff") antifreeze. Pump the whole gallon through the system into the holding tank. Do not reconnect head intake hose to the through-hull.

3.Manual toilet: Pump the head enough time to make sure the antifreeze gets all the way through the toilet and into the tank.

4. After the boat comes out of the water, open all the sea cocks to drain any trapped water. (Obviously you won't do this if the boat will remain in the water.)

Do not use antifreeze in a Lectra/San or PuraSan. Follow manufacturers instructions to winterize all Type I and II MSDs. Those instructions are in the owners manuals...if you don't have one, get one...you can download if from the mfrs website.
 
Nov 18, 2013
171
Catalina 310 Campbell River
On Vancouver Island we sail all year so we don't have to worry about it like others out east.
 
Oct 3, 2011
825
Anam Cara Catalina 310 Hull #155 155 Lake Erie/Catawba Island
Thanks Peggy, as always you come through for those of us that only sail, unfortunately, 6 months of the year and HAVE to be sail-less for the rest of the year. You always provide sage advice!
 
Dec 2, 1997
8,708
- - LIttle Rock
I'm always glad to help when I can. But I can't help wondering why we're talking about winterizing in the middle of June??? I know the season is short in the northern latitudes, but most of the boats up there have barely been launched!

I'm reminded of the old joke. Some southerners asked a northern friend what activities they enjoyed during the summer. The answer came back, "If it falls on a weekend, we try to have a picnic."
 
Mar 26, 2011
3,399
Corsair F-24 MK I Deale, MD
The only change I would suggest is to install proper winterizing valves (a Tee, a valve, and a hose). It takes a few hours to install all of this on all of the systems, but the time is paid back the very next winter. I have such valves on my AC, head, fresh water, and engines. Winterizing all of them takes at most, 30 minutes, as well as reducing glycol usage and spillage. Mistakes and breakage are avoided.

Also:
  • Use EG in the head and engine--neoprene parts stiffen in PG.
  • Remove clear strainers--PG causes some of them to craze in just a few seasons.
 

jerry

.
Jun 9, 2004
64
Catalina 320 500 Stockton, Mo.
I use a little grain alcohol. Winterizes, sanitizes, and party in the spring!
 
Mar 26, 2011
3,399
Corsair F-24 MK I Deale, MD
I use a little grain alcohol. Winterizes, sanitizes, and party in the spring!
I'm hoping this was a joke.

a. It needs to be >25% alcohol to sanitize. Otherwise it just ferments. That's over 50% booze, which will be $$$ even with bottom shelf. Just google "sanitize ethanol" and you will learn this is true. Or take 50/50 booze and water and leave it out for a few months. Nasty.
b. Ethanol will shorten the life of he hoses and the head.
c. Corrosion can be an issue, particularly if it ferments.

PG is a much better choice. Cheaper too.

Perhaps the most common mistake is not using enough. Yes, it could freeze, but the larger problem is that it will ferment, go nasty, and you will struggle to get the taste out of the plumbing. This is actually the "chemical" taste folks complain about. The PG (or alcohol) must be >25%.
 
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Likes: njlarry
Aug 13, 2012
533
Catalina 270 Ottawa
For the water heater we installed this kit to bypass the heater. Once the kit is installed you simply turn the valve to the bypass position, open the heater drain and the pressure relief valve and the heater drains completely. Obviously do this before you pump the system full of antifreeze.
This kit is even better (two valves, so the water heater is completely isolated): https://www.amazon.com/Camco-35953-...22&sr=1-1&keywords=rv+water+heater+bypass+kit
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
or the water heater we installed this kit to bypass the heater. Once the kit is installed you simply turn the valve to the bypass position, open the heater drain and the pressure relief valve and the heater drains completely. Obviously do this before you pump the system full of antifreeze.
Jk, read the instructions again. You leave the heater full of of potable with the bypass closed until you finish pushing AF through the plumbing then you open and drain the heater. Avoids having to fill heater with AF.
 
Nov 18, 2010
2,441
Catalina 310 Hingham, MA
Jk, read the instructions again. You leave the heater full of of potable with the bypass closed until you finish pushing AF through the plumbing then you open and drain the heater. Avoids having to fill heater with AF.
Sounds right. I haven't done it in 4 years, so I was typing from memory. Not much need to winterize in the Caribbean :)
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Lucky dog! Been a long cold wet spring up Boston way!
 
Sep 23, 2009
1,475
O'Day 34-At Last Rock Hall, Md
This kit is even better (two valves, so the water heater is completely isolated): https://www.amazon.com/Camco-35953-...22&sr=1-1&keywords=rv+water+heater+bypass+kit
Two BIG cautions.
One, it matters which way the valves are oriented. The instructions on my unit did not mention this and first I only had the loop feeding the heater so the antifreeze would not loop thru the plumbing .
Two, as Gunni points out, the heater still has to be emptied and the by pass kit alone makes no provision for this.