Water tank in winter

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mick

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I’ve finished the season with the boat out of the water and a full freshwater tank. Any reason why I can’t just leave it? Freezing is unlikely to be an issue.
 
We live aboard for a week at a time, now and again in the winter, even though the boat is ashore. Each time we leave, I make sure all the pipework is empty, but leave the tanks 3/4 full. It would have to be seriously cold for a long time to freeze the water in the tanks. I hope!
 
mick said:
I’ve finished the season with the boat out of the water and a full freshwater tank. Any reason why I can’t just leave it? Freezing is unlikely to be an issue.
Click to expand...

Even if freezing was impossible (not just unlikely), I would take fall as an opportunity to pump the tank down, clean a little, and pump DRY. In that way it will not be nasty when you come back.

You don't put glasses away dirty in the kitchen. You put them away clean. It's nicer that way. Good sanitation starts with cleanliness, and there is no cleaning or commissioning process that is as good as laying the tank up clean and dry.
 
I am paranoid about this, in 2010/11 on a previous boat we had a really hard winter ashore near Oban. I had drained the system , but didn't drain the calorifier. The water pump, and calorifier were both burst ( even though the boat had heating and dehumidifier running). Whilst the large body of water in the tanks may be safe from a cold snap, the water in taps, pumps and small diameter pipes like calorifiers isn't. So its alcohol or food grade antifreeze in our system ever since as an extra precaution.

I wonder if salt could be used to protect a water system cheaply?
 
stevepick said:
I had drained the system , but didn't drain the calorifier.
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I discovered the hard way that if you just run the taps until the water pump is pumping air, you haven't necessarily drained the calorifier. In fact in my boat, the calorifier will be completely full. I went through two calorifiers before understanding this (easy to forget one mistake of many that you made a year ago).
 
If you have a calorifier, it may still be full when your main tank is dry. I have to crack open the relief valve on the calorifier, attach a hose to the fresh water system and siphon it out. (Not forgetting to prevent air entering by closing the taps at the sinks!)
 
Dull Spark said:
If you have a calorifier, it may still be full when your main tank is dry. I have to crack open the relief valve on the calorifier, attach a hose to the fresh water system and siphon it out. (Not forgetting to prevent air entering by closing the taps at the sinks!)
Click to expand...

If air doesn't get in from somewhere, how's the water going to get out?
 
Air gets in via the cracked open pressure relief valve. (It has a red knob on top that takes a small turn to open it. )
 
macd said:
If air doesn't get in from somewhere, how's the water going to get out?
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I think DS means that if the taps are open air entering through them will break his syphon.
Presumably the reason he cracks open the relief valve is to allow air to enter the calorifier. If he is draining via the cold water system opening a hot tap might save messing with the PRV
 
Having drained the system, the instructions on my boat are to drain the pump as well, so this is what I have always done, by detaching the hoses.
 
I have topped up my water tank - but my boat is on the south coast and I visit it once a week. (I like to make a cup of tea....)
 
neil_s said:
I have topped up my water tank - but my boat is on the south coast and I visit it once a week. (I like to make a cup of tea....)
Click to expand...

You would in any case be very unlikely to get a freeze-up if the boat is in the water, but ashore is a different matter. Unfortunately, my tank is almost full and I am due out next week, so I can foresee a lot of pumping.
 
mick said:
I’ve finished the season with the boat out of the water and a full freshwater tank. Any reason why I can’t just leave it? Freezing is unlikely to be an issue.
Click to expand...
Freezing is the only risk . I assume your boats location is not liable to significant frost.
However I see you say you will drain it down. I think that is probably wise.
On re-filling the tank in the spring I flush most of the first tankful through the pipes . I used to use a sterilising fluid for the spring flush but have given up with that after advice on a forum, possibly this one, suggested a good flush with fresh tap water should be sufficient. The chief officer and I do not drink tank water.
 
You wanna make hot drink in boat in winter - take water with you then. Drain down all water, calorifier also make empty, can just drain into bilge and pump out bilge? Most simple! Take off shower valve and pipes from pump, be certain pump got no water left inside, drain all pipes, pump car anti-freeze in bucket down toilet so not freeze toilet, do same engine in sea-cock filter - turn off sea cock first huh so running through engine from bucket?

Then you go home very happy man, boat safe if very cold not got big problem for vacation time next year.
 
If you don't drink tank water...
a. ...cleaning probably doesn't matter to you, and...
b. ... why comment on how to best treat the system, since you are maintaining your potable water system to a non-potable standard?

Seems weird to me. Can you use the water to cook or wash dishes? I maintain my system to a potable water standard and don't waste plastic or effort hauling bottles. It's not that hard.

http://sail-delmarva.blogspot.com/2014/06/drinking-water-filtration-short-version.html
 
thinwater said:
Even if freezing was impossible (not just unlikely), I would take fall as an opportunity to pump the tank down, clean a little, and pump DRY. In that way it will not be nasty when you come back.

You don't put glasses away dirty in the kitchen. You put them away clean.
Click to expand...

You also put them away dry. You can't dry out the inside of a water tank, so it's a choice between leaving it full of water or leaving it damp and full of air. Would you rather drink out of a glass which had been under water for six months or sitting around damp for six months?
 
I drain my fresh water in to a tub via the shower hose then I put the engine intake hose into this & use it to flush the exhaust etc. I add some extra water to give it a good flush then on the last drop I stick some antifreeze so no water will freeze inside the engine or exhaust.
After that I disconnect the calorifier hose & drain it off from the lowest point.
I threw the relief valve away years ago- waste of time- only drips & the spring broke.
 
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