Winterising the water tanks

[charles_reed]

I find it takes a long time to get the taste of sodium hypochlorite out of the system, so avoid it like the plague.
Here in the Aegean, below zero temperatures are not sufficient a risk to drain the tank and associated pipework, though it's probably adisable on the UK east coast.
The big problem with any water left in pipework or tank is the development of anaerobic bacterial infection (H2S - rotten egg small). I've found sodium hypochlorite relatively ineffective for prevention. However, for the last 10 years I've found that one of the silver chelate compounds, put into the tank and pumped into the pipework works admirably in preventing this infection. Protection is claimed to work for 6 months, though I've found that after 2-3 months of use with ordinary water the infection recurs.
The compound I use (I've only been able to find it outside the UK) is AquaClean by Yachticon G Nagel. €12 for sufficient to treat 1.2 tonnes of water - the liquid is far better than the solid form.
When you come back to the boat you just use the water normally - silver nitrate is a very effective, but harmless to humans, bactericide - in use for over 150 years.

 

[jimbaerselman]

I find it takes a long time to get the taste of sodium hypochlorite out of the system, so avoid it like the plague.

An acid flush does the trick. Diluted vinegar will do 1/10. See item 5 on this link

 

[Mistroma]

I find it takes a long time to get the taste of sodium hypochlorite out of the system, so avoid it like the plague.
Here in the Aegean, below zero temperatures are not sufficient a risk to drain the tank and associated pipework, though it's probably adisable on the UK east coast.
The big problem with any water left in pipework or tank is the development of anaerobic bacterial infection (H2S - rotten egg small). I've found sodium hypochlorite relatively ineffective for prevention. However, for the last 10 years I've found that one of the silver chelate compounds, put into the tank and pumped into the pipework works admirably in preventing this infection. Protection is claimed to work for 6 months, though I've found that after 2-3 months of use with ordinary water the infection recurs.
The compound I use (I've only been able to find it outside the UK) is AquaClean by Yachticon G Nagel. €12 for sufficient to treat 1.2 tonnes of water - the liquid is far better than the solid form.
When you come back to the boat you just use the water normally - silver nitrate is a very effective, but harmless to humans, bactericide - in use for over 150 years.

Alternatives based on Silver will be very effective. However, if you ever find yourself stuck and short of other options then you can use bleach and get rid of the taste quite easily. See post #19.

 

[JumbleDuck]

Many thanks. All I need now is to find a sodium metabisulphite shop!

Home brewing suppliers generally have it.

When you come back to the boat you just use the water normally - silver nitrate is a very effective, but harmless to humans, bactericide - in use for over 150 years.

It's only harmless in very low concentrations, and even then there are possible cumulative effects. See https://en.wikipedia.org/wiki/Silver_nitrate#Safety. Still, this could make an interesting use for "Smelly Decky".

 

[JumbleDuck]

Many thanks. All I need now is to find a sodium metabisulphite shop!

Home brewing suppliers generally have it.

When you come back to the boat you just use the water normally - silver nitrate is a very effective, but harmless to humans, bactericide - in use for over 150 years.

It's only harmless in very low concentrations, and even then there are possible cumulative effects. See https://en.wikipedia.org/wiki/Silver_nitrate#Safety. Still, this could make an interesting use for "Smelly Decky".

 

[charles_reed]

Home brewing suppliers generally have it.



It's only harmless in very low concentrations, and even then there are possible cumulative effects. See https://en.wikipedia.org/wiki/Silver_nitrate#Safety. Still, this could make an interesting use for "Smelly Decky".

Anything in excessively high concentrations is dangerous - you can kill yourself by drinking too much water.
The concentration is about 0.00005% ie 5ml to 100 litres.
One should beware swallowing Wikepedia without filtration

 

[demonboy]

It's rare we're away from the boat for more than a few weeks at a time but this summer I was in the UK for two months and had to leave water in the tanks for my cat who was being looked after by a neighbour. There wasn't much water in the tanks and it wasn't chlorinated water either, it was filtered local water (our watermaker is currently decommissioned). After two months when I returned to the boat I noticed the water smelt a bit stale, I guess because there was no constant movement of water in the tanks, either from sailing or from filling them up. We're also in the tropics, which has to make a difference.

When I have left the boat I always empty the tanks. I was taught: diesel tanks full, water tanks empty. When I return to the boat I pour a few splashes of household bleach into the feeder pipes, add enough water to cover the bottom of the tanks (30 litres per tank at a guess), run the water through so the tanks are empty or until the water has stopped smelling, then fill up. I do this every season as a rule.

I normally filter the water if I'm taking it from a marina because a) I dislike the taste of chlorinated water and b) you shouldn't be flushing the watermaker with chlorinated water, even though the watermaker as a carbon filter in-line. In this case, however, I purposely used the chlorinated marina water to sit in the tanks for a night to kill off any possible nasties.

 

[JumbleDuck]

One should beware swallowing Wikepedia without filtration

As one should beware before swallowing claims of miraculous powers for anything, whether cider vinegar or silver nitrate.

 

[charles_reed]

As one should beware before swallowing claims of miraculous powers for anything, whether cider vinegar or silver nitrate.

How sad that one so young should be so cynical.

Having used silver chelate compounds for 12 years I know they work.

- and I'm sure you're not calling me a liar? Because that would make you ill-mannered as well as cynical.

 

[JumbleDuck]

How sad that one so young should be so cynical.

Having used silver chelate compounds for 12 years I know they work.

- and I'm sure you're not calling me a liar? Because that would make you ill-mannered as well as cynical.

People who fall for miracle cures are gullible, not dishonest, unlike the people who sell them.

Here's an interesting article debunking the claims made for silver: https://www.sciencebasedmedicine.org/hi-ho-silver/. The good news is that, like most placebos, it probably won't do much harm.

 

[RichardS]

Here's an interesting article debunking the claims made for silver: https://www.sciencebasedmedicine.org/hi-ho-silver/. The good news is that, like most placebos, it probably won't do much harm.

I must say I've never heard those claims for silver. If anyone suggested to me that ingesting silver was a good idea I would suggest a visit from the men in white coats!

Using silver and certain silver compounds as an external bactericide is well-known and well-documented and standard practice in many applications such as water sterilisation.

Richard

 

[JumbleDuck]

Using silver and certain silver compounds as an external bactericide is well-known and well-documented and standard practice in many applications such as water sterilisation.

Of course, but the "alternative medicine" (ie "not actually medicine") world takes it to extremes. Water's great for washing your car, but homeopaths claim it cures cancer too ...