Water Tank advice

[David R]

We have a steel water tank on board - there is the usual course strainer on the outlet before the pump and I intend to fit a fine filter on the line to the cold taps. However, although I have used purification tablets, the water is still a bit on the brown side of pleasant! I presume I'm going to need to drain off the tank and then ....???? Can anyone provide some advice on how to clean the tank?

 

Also, is there a better way to drain the tank than running the pump and taps?

 

Thanks very much.

 

David

[DHutch]

I presume this is a integral or otherwise steel tank which is now starting to rust. (if its a plastic or stainless tank, im wrong)

 

In this case, in the long term, what is wants is painting!

 

In the short term, if you run it all out of the taps (may need to do it in sessions, if its a bit tank, because most pumps arnt continuously rated and get hot over time) and re fill it. Your likely to die, and if it still tastes a bit off, you can use a small bottle contrainer to carry secondard 'drinking water' around.

 

But in the lock term, its going to be a case of opening up the tank, draining it, drying it, scraping all the loose crap off, redry, rust converter (vactan et al), dry really well, and several coats of suitable paint. Sod of a job, but the only real fix.

 

Some put rubber liners into steel tanks, which seam to work well. But even then i would start by drying and painting the tank.

 

If you use the search (hides) and put in 'water tank painting' or similar i imagine you should be able to find a fair few threads.

 

 

Daniel

[NB Alnwick]

We have a steel water tank on board - there is the usual course strainer on the outlet before the pump and I intend to fit a fine filter on the line to the cold taps. However, although I have used purification tablets, the water is still a bit on the brown side of pleasant! I presume I'm going to need to drain off the tank and then ....???? Can anyone provide some advice on how to clean the tank?

 

Also, is there a better way to drain the tank than running the pump and taps?

 

Thanks very much.

 

David

 

I am presuming that this is a mild steel tank rather than a stainless steel job. If the water is brackish and stained, it may be that the coating on the inside of your tank has failed. Is there a hatch cover or inspection plate that enables you to access the inside of the tank, clean it out and re-coat it with a waterproof paint?

 

I see that Daniel and I have drawn the same conclusions . . .

[Guest]

I undertsand some people use either Vactan or Fertan (can,t remember which, but at least one is water potable.) Seemingly this seals and converts the rust without the hassle of using bitumen. Never done this personally.

[alan_fincher]

I am presuming that this is a mild steel tank rather than a stainless steel job. If the water is brackish and stained, it may be that the coating on the inside of your tank has failed.

Pedant alert.

 

My understanding of "brackish" is that it has got salt in it, like sea water, (or I think being exact at lower salinity than sea water).

 

I can't see why a steel narrow boat tank would end up with salt in it.

 

I understand some people use either Vactan or Fertan (can't remember which, but at least one is water potable.) Seemingly this seals and converts the rust without the hassle of using bitumen. Never done this personally.

The one people have said they use, (on here at least) is Vactan.

 

Personally when I tried to use Fertan on a hull, and thought I had followed the instructions, it did not do what it said on the bottle, and rust quickly formed on the "Fertaned" surface, so I had to scrap it all, and start again.

 

I wasn't confident of just "Vactanning", despite the advice of others, so went for that first, then over-painted with the potable blacking, (a pig of a job, but nothing compared to trying to de-rust the tank in the first place! )

 

I can't easily get the lid off to see how it's faring, but it has already been massively more successful than when we paid a marina engineer lots of money to (allegedly) clean and re-black the tank. We had rust coming out of the taps within a year, and there wasn't a lot of blacking in there when I did finally climb in and get to work.

[ChrisPy]

the advantage of Vactan is that is has been certified for use in tanks for foodstuffs, etc.

 

I am not convinced it is a total solution either and will be retreating and overpainting it this year.

 

 

Cat, can you recommend a non-toxic potable blacking?

I checked a few (e.g. Aquaseal) and you can't use them in confined spaces without respirators.

Edited April 8, 2010 by ChrisPy

[nb Innisfree]

the advantage of Vactan is that is has been certified for use in tanks for foodstuffs, etc.

 

I am not convinced it is a total solution either and will be retreating and overpainting it this year.

 

 

Cat, can you recommend a non-toxic potable blacking?

I checked a few (e.g. Aquaseal) and you can't use them in confined spaces without respirators.

 

'Intertuf' by International Paints

[casper ghost]

I have 2 25 litre water tubs in the kitchen and pump the water to a tap with a submersible pump, this I use for drinking, it means I get clean, nice drinking water. The front water tank is used for everything else but never for drinking.. I think this system works well and seems suprisingly underused by most. It makes the plumbing easy with no expensive gadgets to fit and no problem with dirty drinking water.

[soldthehouse]

I have 2 25 litre water tubs in the kitchen and pump the water to a tap with a submersible pump, this I use for drinking, it means I get clean, nice drinking water. The front water tank is used for everything else but never for drinking.. I think this system works well and seems suprisingly underused by most. It makes the plumbing easy with no expensive gadgets to fit and no problem with dirty drinking water.

Gold star to Casper

[springy]

Hi

 

As far as emptying the tank goes, assuming you have an access cover, when I needed to do mine

I just temporarily rigged up my spare bilge pump (clean and unused at that time) & chucked it in the

tank to pump the water over the side - saves running the domestic pump for hours & probably does

a much quicker job.

 

repainting the inside of the tank is just one of those evil jobs which has to be done.

 

springy

[David R]

Thanks very much for all the advice!

 

Yes, it is an integral steel tank. No, there is no inspection hatch - just the filler port - the tank sits beneath the well deck and behind the gas locker.

 

David

[NB Alnwick]

Pedant alert.

 

My understanding of "brackish" is that it has got salt in it, like sea water, (or I think being exact at lower salinity than sea water).

 

I can't see why a steel narrow boat tank would end up with salt in it.

 

Salt is used in some water treatment processes, particularly in areas where the water is naturally hard, and, if allowed to build up, it will corrode mild steel.

[Mrs Tawny Owl]

HI I put my experience of our solution to this problem in another thread. Here it is to save me retyping.

 

this thread

 

Hope I got this right, my first attempt at referencing another thread

 

Sue

[alan_fincher]

Yes, it is an integral steel tank. No, there is no inspection hatch - just the filler port - the tank sits beneath the well deck and behind the gas locker.

That would be highly unusual, because the nature of these beast means that someone really does need to get in there every few years.

 

It may sound like a totally daft question, as I don't know your boat, but are you absolutely sure there is nothing buried under some kind of over-painting with deck paint, or the like ?

 

Who built the boat, and how old is it, please ?

 

 

HI I put my experience of our solution to this problem in another thread. Here it is to save me retyping.

 

this thread

 

Hope I got this right, my first attempt at referencing another thread

 

Sue

I'm not sure how you could use a "rubber liner" solution if the water-space genuinely has no removable hatch.

 

I think to be confident of such a solution you would still need to de-rust, treat, and paint the area it was going in to.

 

I shudder to think what pitting might be inside a completely sealed integral tank, if it has never been possible for anyone to get inside it, (if the boat is any age at all, of course, which I'm assuming it is).

[springy]

Thanks very much for all the advice!

 

Yes, it is an integral steel tank. No, there is no inspection hatch - just the filler port - the tank sits beneath the well deck and behind the gas locker.

 

David

 

In that case I guess the first job is out with the angle grinder & cut an access hatch !

 

Make it as big as you reasonably can - it will make climbing in and painting that bit easier.

 

You can either cut carefully & re use the piece you have cut out as the hatch cover, but you

will need to add supports (flat or angle iron) to the underside - probably by welding, this has

the advantage of leaving the upper surface of the deck reasonably flat. Alternatively you can

simply obtain a larger piece of steel which overlaps all around the hole and use this as the

hatch cover, this does result in a slight step in the deck surface (but overall is an easier

method). In either case you can secure the cover using countersunk screws either tapped

directly into the steel of the deck, or (better) using rivnuts, and a bead of suitable sealant.

 

It is tempting to cut almost all of the deck out - leaving approx 2" all around the outside,

and have a new deck plate to overlap the 2" stub - this may be ideal BUT beware it

may be impossible to get the new deck plate into position depending on the angle of the

hull sides & width of the gunnel top. (and pretty heavy & difficult to remove again)

 

springy

[DaveR]

I have just opened, checked and closed the tank on the Bensham.

 

Firstly I lashed out £25 on a pond pump from Screwfix which does 150 litres/minute. First time I haven't run the domestic waterpump to empty the tank. Conclusion, should have bought the pump years ago. Just lash up the float switch to the discherage line so that the pump runs constantly and it takes things down to the last few litres.

 

The tank is 1000 litres and is accessed through a flat hatch under the foredeck / cratch area fixed with 16 machine screws. The hatch is big enough to let me get into the tank for cleaning and painting.

 

For protecting the steel I use 'black' the same as most use on the hull. I do not know which make it is but on the tin, one of the uses is for the protection of drinking water tanks and is approved by the World Health Organisation. Obviously it is used for some of the water projects they do in far off lands.

 

Last did the tank 4 years ago (clean and paint) and after checking this year it looks as if I will be doing it again in about two or three years time. There was a small amount of rust sediment in the bottom of the tank, about a small glass full, coming from three or four large blisters in areas I missed when doing the painting last time.

 

Dave R

[Keeping Up]

Now that IS confusing! I had to look at posts 1 and 16 three times to work out why the OP was answering his own post in this way, before my brain resolved the slight difference in names!

[Grace and Favour]

Now that IS confusing! I had to look at posts 1 and 16 three times to work out why the OP was answering his own post in this way, before my brain resolved the slight difference in names!

:lol: you and I both!

[David R]

That would be highly unusual, because the nature of these beast means that someone really does need to get in there every few years.

 

It may sound like a totally daft question, as I don't know your boat, but are you absolutely sure there is nothing buried under some kind of over-painting with deck paint, or the like ?

 

Who built the boat, and how old is it, please ?

 

 

 

I'm not sure how you could use a "rubber liner" solution if the water-space genuinely has no removable hatch.

 

I think to be confident of such a solution you would still need to de-rust, treat, and paint the area it was going in to.

 

I shudder to think what pitting might be inside a completely sealed integral tank, if it has never been possible for anyone to get inside it, (if the boat is any age at all, of course, which I'm assuming it is).

 

Well she is an old dear - 1982 and you may well be correct - there is any amount of paint layers in the well-deck - I shall look closely! She was built by John South Boats.