winterizing fwc

[bobtookmm]

do folks with fwc systems drain them for winter or rely on a fresh change of antifreeze?

[joe_db]

I have winterized a ton of FWC boats for customers back in the day and we just ran antifreeze through the raw water side. We did not routinely change out the anti-freeze unless asked. I would check and make sure it was anti-freeze and not water by eye and with an antifreeze tester to check the strength.
For my own boat this winter I never fill it with anything other than premixed 50/50, so I am good to go. No need to drain it or change it.

[toddster]

I have a cheap plastic Tee in the raw water intake, with a hose fitting. Easy to draw up a bucket of antifreeze into the system if a cold snap is coming. Some expensive seacocks have a fitting right on them for that purpose.

That said, I was out of the country during the last (unseasonal, unexpected) cold snap and did nothing. The boat came through just fine. The same cannot be said for my greenhouse and workshop. Still working on some of the damage.

[joe_db]

Good thing about FWC is even a bad freeze would only damage the heat exchanger and maybe the raw water pump.

[BunnyPlanet169]

Good thing about FWC is even a bad freeze would only damage the heat exchanger and maybe the raw water pump.

And the incoming water strainer, and the water lift muffler, or in my case the jacketed exhaust. That's a lot of damage. $

'Bad freeze' in Maine is about November to say May. When the water is that hard, for that long, we ski on it. ;>)

Back to the OP, on my engine (still RWC) it's drain everything as best you can. Block, manifold, pump, strainer, muffler.

In the future, it will be drain and blow out the RWC circuit (strainer, RW pump, RW side of the HX, exhaust) and make sure the block, header tanks, everything on the FWC side look sickly yellow green with antifreeze.

[joe_db]

Forgot about strainers, we had two boats sink at the dock a couple years ago with the bad freeze when the strainers froze and then shattered

[ndutton]

Forgot about strainers, we had two boats sink at the dock a couple years ago with the bad freeze when the strainers froze and then shattered

I'm not a snow belt guy but my immediate thought was Huh? Why weren't their raw water intake valves closed??

[bobtookmm]

thanks again

i really value the shared insights from everyone
bob

[67c&ccorv]

I'm not a snow belt guy but my immediate thought was Huh? Why weren't their raw water intake valves closed??

My thoughts exactly.

[joe_db]

Mine is closed when winterized.
The issue seemed to be that the engine room heater had done fine for many years, but that winter was so cold that the engine room went below freezing when it never had in the past

My thoughts exactly.