[C320-list] Water System Winterization Using the Bilge Pump!

[Robert E. Sloat]

I have hull 894 which is a 2002 320 and can recommend a winterization procedure for the fresh water system used in the Chicago area with cold winters which does not require a compressor, shop vac or many gallons of RV antifreeze.

Hull 894 has a noisy bilge pump that sucks.  I mean that in the most positive way.  It is a diaphragm type that can draw a pretty good head.  This probably won't work with most bilge pumps that cannot draw a head.  You basically suck out water from the system and suck air in clearing all lines using the bilge pump which is connected to the hot water tank drain with an air tight hose.  

The trick is to get around 8 feet of flexible plastic hose with an OD that matches the ID for the intake hose for the bilge pump.  This will connect the hot water heater drain to the bilge pump. For my hull, Catalina has a hose roughly 3/4" ID as the bilge pump pick up which sits at the bottom of the bilge.  I used flexible plastic hose with 5/8" ID and 3/4" OD and a fitting that will attach this hose to the water heater drain valve which is a standard garden hose spigot.  This is available at most hardware stores.

Drain each water tank by just running the water pump and opening a faucet.  A little water will remain in the tank which will be dealt with later.  

Then hook up the hose to the hot water heater so it is tight with no air leaks.  Stick the other end of the hose inside the bilge pump inlet hose to get a tight seal.  On my boat the 3/4" hose fits very snuggly into the bilge intake hose.  Temporarily tape this joint if necessary to eliminate suction leaks.

Make sure the water pressure pump is off, open a faucet the farthest from the hot water tank (I opened the cockpit shower hot water valve)  open the water tank drain valve and then turn on the bilge pump and watch the water get sucked out of the water tank.  My bilge pump will also suck air in the open faucet clearing water out of the line.  When it looks like most of the water is out of the hot water tank start opening just one faucet at a time until all of them and connected lines are empty.  At the end, close all the faucets and disconnect the Whale rigid plastic pipe from the discharge side of the fresh water pump and turn on the bilge.  This will clear out any water in this line connecting the pump to the rest of the water system.  The system is now drained except for a little water that remains in the water tank.  For the last few seasons I have just left it there without any problems.

I followed up with my compressor to blow out the system to see if any additional water could be blown out and the finding was negative.  No more lugging this to the dock.

Now for the winterizing the lines that connect the water tanks to the water pump.  The pump is located under the main berth on the port side.  Get a short piece of Whale 15 mm OD rigid plastic water pipe.  This is the type used in most Catalina's of recent ilk.  I used a 6 " piece.  Attach it to a flexible plastic hose with a 5/8 " ID and then insert the pipe into the Whale fitting on the discharge side of the water pump.  I used the same plastic hose that was used for draining the hot water tank.  The 15 mm OD Whale pipe fits snuggly into a 5/8 " ID hose.  Pour a little (about 1/3 gallon) of RV antifreeze into one of the empty water tanks, open the valve that connects it to the pump making sure the valve to the other tank is closed, stick the end of the hose into a gallon bottle, turn on the water pump and run it until antifreeze comes out.  My tanks when drained empty using the water pump have about 8 oz of water remaining in each of them when empty.  If yours have more, adjust the amount of antifreeze used.  Do the same thing with the other tank.  Leave the hose connected to the water pump so in the spring you just flush out the water tanks by draining to the bilge with a few gallons of water by passing the hot water heater.  Then hook up the pump to the Whale line and you are ready to fill the hot water tank.  And no lingering antifreeze smell or taste in the fresh water.

You still need to winterize the manual bilge pump, the regular bilge pump, the refirgerator drain, shower sump and the head with antifreeze.

Bob Sloat
Savannah Hull 894