Water System Winterization

Bob&Jilly

R27-OB Portland OR Lynnsanity II
Joined
Mar 13, 2025
Messages
102
Location
Fargher Lake WA
Fluid Motion Model
R-27 (Outboard)
Hull Identification Number
FMLT2757*818
Vessel Name
Lynnsanity II
It appears that some folks just run thier water tank dry and others blow out the lines with a compressor - not sure which is best or necessary.
Further, when I pump out all the water in the tank the pump will not shut off. If I add some water and try the faucet it will shut off immediately when there is water in the tank. - is that the usual? I am wondering if the pump is just sucking air and may not be able to build up enough pressure to shut off.
Thanks
 
I drain the water tank and use antifreeze, and one at a time run each faucet until they run pink. BUT this is a hassle in the spring due to having to do several flushings.

Next year, I will modify the piping to allow me to use a small battery-powered compressor to blow the lines out.
 
The freshwater piping on the R27 is PEX which can withstand freezing temperatures as long as it's not full of water and under pressure.

I don't use anti-freeze. I don't blow down my freshwater system with compressed air. I also don't waste cheap vodka. I pump the tank empty by simply turning on the water pump and opening all the faucets (head, galley, transom) until water no longer comes out. Then at the hot water heater, I disconnect the hot and cold connections and let it drain to the bilge. I take the transom shower, open the valve to halfway between hot and cold, and open the water shutoff on the nozzle and hold this way above my head to let the water in the metal hose drain out the connections at the hot water heater (which are still disconnected). Once water stops flowing out, I reconnected the hot and cold connections to the hot water heater, and I'm done. I just did this today while we were coming up the river, to Dagmars (we spent the weekend in Edmonds with the RHYC on our Day After Thanksgiving weekend cruise). Then I dry the bilge out with a bilge sponge and a bucket.

That's all I do for the freshwater system. This will be year 6 doing it this way. Boat is stored out of the water, on blocks, same as on a trailer and will freeze to 10degrees for a week to 10 days several times throughout our winter.

This photo illustrates the hot water heater to be the low point in the system.
 
The freshwater piping on the R27 is PEX which can withstand freezing temperatures as long as it's not full of water and under pressure.

I don't use anti-freeze. I don't blow down my freshwater system with compressed air. I also don't waste cheap vodka. I pump the tank empty by simply turning on the water pump and opening all the faucets (head, galley, transom) until water no longer comes out. Then at the hot water heater, I disconnect the hot and cold connections and let it drain to the bilge. I take the transom shower, open the valve to halfway between hot and cold, and open the water shutoff on the nozzle and hold this way above my head to let the water in the metal hose drain out the connections at the hot water heater (which are still disconnected). Once water stops flowing out, I reconnected the hot and cold connections to the hot water heater, and I'm done. I just did this today while we were coming up the river, to Dagmars (we spent the weekend in Edmonds with the RHYC on our Day After Thanksgiving weekend cruise). Then I dry the bilge out with a bilge sponge and a bucket.

That's all I do for the freshwater system. This will be year 6 doing it this way. Boat is stored out of the water, on blocks, same as on a trailer and will freeze to 10degrees for a week to 10 days several times throughout our winter.

This photo illustrates the hot water heater to be the low point in the system.
Thanks so much!
 
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