Clean water tank

[Steve Manc]

Hi.

I have a narrowboat built by  Coal Craft. I am considering opening the water tank with a view of cleaning it out. The tank is built in under the forward deck and gas locker. The access point is a hatch in the deck on the foreward deck. 

 

Has anyone done this?

What challenges did you have?

Did you paint it once cleaned?

What undercoat and paint did you use?

What would you do if you started the task a second time?

 

Thanks 

[system 4-50]

Quite a few threads on here about this.

[Sea Dog]

59 minutes ago, Steve Manc said:

I have a narrowboat built by  Coal Craft.

Is it a black one?

 

[Jen-in-Wellies]

If there is a hatch in to the tank in the front deck, then it is a built in steel tank. Not had a boat with one myself, but the seal around the hatch can leak, leading to gunge getting in. Also the tank needs regularish painting with special paint. Search for built in tank, potable water paint, painting water tank, derusting water tank etc. Should find you the information you need. Sounds a horrible job, curled up inside derusting and painting. I've painted the inside of my gas locker, which is similarly unpleasant.

Jen

[dor]

My last boat had a similar setup.  I didn't open the tank in the seven years we had the boat and doubt it had been opened for some time before, if at all.

Peering into the filler, I could see little rusticles but nothing actually swimming.

 

I had a decent filter on the galley cold tap but didn't use anything else and neither of us suffered.  I think the tanks settle down and a coating of rust on the inside is really just as clean as a coating of bitumen.  This does assume of course that nothing particularly nasty gets into the tank, but we were always careful to make sure the end of the hose was clean and the deck hatch was well sealed. But then the same would apply if you blasted the inside of the tank and re-coated it every year.

[mrsmelly]

Ive done it on a colecraft that I owned. It was old and I know hadnt been touched since new so about twenty years. I got the cover off in the well deck and hung inside ( twenty years ago ) I couldnt do that now lol. It was a bit manky and a bit rusty so I washed it down and left it to dry for a day or two in very hot weather then banged a couple of coats of bog standard black bitumen on it and let it dry. Bit of discloration in the water for a day or so after but was fine and dandy. We always drink from the tank.

Edited May 31, 2020 by mrsmelly

[Machpoint005]

I'm about to start exactly the same project with my Colecraft. We've had nasty discoloured wated for a while now so it's well overdue. I anticipate the first problem will be to remove the screws and break the seal - there will be several coats of paint to chip away. To that end I have provided myself with a set of SDS chipping tools (no pansy battery-operated drills for me!). 

 

 

1 hour ago, Jen-in-Wellies said:

Sounds a horrible job, curled up inside derusting and painting

 

I doubt I'll be able to get in. I'm hoping my arm will be long enough if I can get my head and one shoulder down the hatch. 

[dmr]

Its ColeCraft named after Mr Cole who makes them.

 

It needs doing every few years. Ours was in pretty good condition but still had a few local rust spots throwing up brown rusty things looking like little worm casts, and these had created significant pits in the steel (1.5 to 2 mm). Ours is held down by a lot of fairly big countersunk slotted head screws in stainless steel. I was expecting some trouble but every one came out ok. We have a big 1000l tank and getting inside was ok, a much smaller tank could be difficult and unpleasant.

 

If its a long term boat then bare metal and epoxy is the way to go, otherwise a good scrape and potable blacking. Some people here claim good results with just Vactan.

 

The ideal approach to water tank work is to find somebody else to do it for you. This is not easy. Anybody who has any experience and the ability to do a good job will not want to take on an unpleasant job like this. Search for a good bloke having a short term shortage of money, now might be a good time, or maybe its already too late ?

 

..............Dave

 

 

[BilgePump]

We did it on our nb with built in tank prior to sale a few years ago.  We didn't use it for drinking water but it had started to look quite brown when some hadn't been drawn for a while so it needed derusting and recoating.

Like @Machpoint005 says, the opening bit is the first chore. Quite a few layers of paint been applied since last opened and you'll most probably need an impact driver to shift the screws. We did, (and don't put the driver on the roof or it will sure as eggs is eggs fall in the canal).

Smaller tanks are a pain, you ideally need a young chimney sweep covered in bitumen to twirl around down there! 

[WotEver]

25 minutes ago, Machpoint005 said:

I anticipate the first problem will be to remove the screws and break the seal - there will be several coats of paint to chip away. To that end I have provided myself with a set of SDS chipping tools (no pansy battery-operated drills for me!). 

You might also find an impact driver useful to get the screws out. 

6 minutes ago, BilgePump said:

you'll most probably need an impact driver to shift the screws.

Oh, snap

[system 4-50]

Beware of fumes in confined spaces (if applicable).  

[Machpoint005]

6 hours ago, BilgePump said:

@Machpoint005 you'll most probably need an impact driver to shift the screws.

 

6 hours ago, WotEver said:

You might also find an impact driver useful to get the screws out.

 

I'm thinking my mighty Bosch will do that job, but I'll have my handraulic impact driver too.

 

 

 

Edited May 31, 2020 by Machpoint005

[BilgePump]

2 hours ago, Machpoint005 said:

 

 

I'm thinking my mighty Bosch will do that job, but I'll have my handraulic impact driver too.

 

 

 

You may also want to do it in the middle of nowhere. SDS chisel bits or impact drivers being belted on the top of a half empty water tank makes a heck of noise and on a Sunday afternoon quiet mooring you may be about as popular as the proverbial in the swimming pool.

[David Mack]

On 31/05/2020 at 10:44, WotEver said:

You might also find an impact driver useful to get the screws out. 

Oh, snap

Yes, the screws might do that.

[Machpoint005]

16 hours ago, BilgePump said:

You may also want to do it in the middle of nowhere. SDS chisel bits or impact drivers being belted on the top of a half empty water tank makes a heck of noise and on a Sunday afternoon quiet mooring you may be about as popular as the proverbial in the swimming pool.

 

During the normal working day, on my mooring, and I'll be wearing hearing protection. 

I'll offer E-A-R Plugs to anyone who wants 'em!

[Steve Manc]

Thanks for the replies. I will let you know how I get on when I do it.

[beerbeerbeerbeerbeer]

On 31/05/2020 at 10:22, dmr said:

Its ColeCraft named after Mr Cole who makes them.

 

It needs doing every few years. Ours was in pretty good condition but still had a few local rust spots throwing up brown rusty things looking like little worm casts, and these had created significant pits in the steel (1.5 to 2 mm). Ours is held down by a lot of fairly big countersunk slotted head screws in stainless steel. I was expecting some trouble but every one came out ok. We have a big 1000l tank and getting inside was ok, a much smaller tank could be difficult and unpleasant.

 

If its a long term boat then bare metal and epoxy is the way to go, otherwise a good scrape and potable blacking. Some people here claim good results with just Vactan.

 

The ideal approach to water tank work is to find somebody else to do it for you. This is not easy. Anybody who has any experience and the ability to do a good job will not want to take on an unpleasant job like this. Search for a good bloke having a short term shortage of money, now might be a good time, or maybe its already too late ?

 

..............Dave

 

 

I once climbed inside a gas locker and spent a long sunny day sitting cross legged grinding back to bare metal for someone once. ? 

Nice chap, very nice chap, rewarded me with a lot of beer money. 



 

 

 

[Opener]

Been there, seen it, done it!

Tank access hatch may be bedded down on a gasket - decide what you need and source replacement early in the job. God bless the mechanic who fitted my hex-head bolts 17 yrs ago with suitable lubrication - all came out without a murmer. Be prepared to also do this yourself. Have a good look up ? the water pick up tube - not unknown for it to be partially blocked. Take lots of newspaper to sit on ( In the tank) or soak up damp. How are you going to get residual water out - ?? sponge + bucket. Good torch - it's gonna be dark in there. Have fun - I did?.

 

[dmr]

26 minutes ago, Goliath said:

I once climbed inside a gas locker and spent a long sunny day sitting cross legged grinding back to bare metal for someone once. ? 

Nice chap, very nice chap, rewarded me with a lot of beer money. 



 

 

 

But would you ever do it again? ?

 

The bloke who did our gas locker did a pretty good job, I had a good look in there last week as the BSS is due, and its still perfect.

 

..................Dave

[dmr]

4 minutes ago, Opener said:

Been there, seen it, done it!

Tank access hatch may be bedded down on a gasket - decide what you need and source replacement early in the job. God bless the mechanic who fitted my hex-head bolts 17 yrs ago with suitable lubrication - all came out without a murmer. Be prepared to also do this yourself. Have a good look up ? the water pick up tube - not unknown for it to be partially blocked. Take lots of newspaper to sit on ( In the tank) or soak up damp. How are you going to get residual water out - ?? sponge + bucket. Good torch - it's gonna be dark in there. Have fun - I did?.

 

 

Suck the water out with the spare water pump that you carry, then mop with a sponge. Do it on a warm day and it will be dry in no time. Take lots of paper towel in to mop up your sweat ?. Its quite a big hatch on  a Colecraft, and in the well deck, so lots of light inside the tank.

 

.................Dave

[Bod]

Having done this very job on a Colecraft hull, there are a few tips to pass on.

1. Do not use a powered wire brush inside the tank.  Think black and white minstral impression when you come out!

2. Do this job in hot dry weather, the tank paint is very slow to dry, but be aware of heat stroke.

3. Have a way of continuing the water supply, to the rest of the boat.  You will need a shower at the end!

4 .My boat, the tank lid was held down by 5/16x18 BSW Brass countersink screws, yours may be different.  Mine ended up with M10 s/steel replacements.

5. The seal will need replacement, also the filler cap gasket.

6. Check the water pick up pipe, they have a tendency to rust up to blockage levels internally.

7. Take time to get a properly fitting screwdriver before making any attempt to undo any screws, brass is quite soft and chews up easily.

 

Bod.

[beerbeerbeerbeerbeer]

58 minutes ago, dmr said:

But would you ever do it again? ?

 

The bloke who did our gas locker did a pretty good job, I had a good look in there last week as the BSS is due, and its still perfect.

 

..................Dave

Yes please. 
Always need beer. 
 

But I think the perfection is down to your painty skills. 

Just now, Goliath said:

Yes please. 
Always need beer. 
 

But I think the perfection is down to your painty skills. 

So yes, great way to isolate when working

[Bobbybass]

On 31/05/2020 at 10:22, dmr said:

 

 

If its a long term boat then bare metal and epoxy is the way to go, otherwise a good scrape and potable blacking. Some people here claim good results with just Vactan.

 

 

 

 

My pot of Vactan specifically says...not for potable water tanks.

 

Beware of making sure it is for potable tanks. Some of the bitumen compound is very dangerous.

I ordered a tin for drinking tanks and the supplier substituted a different one,,.which was dangerous.

 

Last year I crawled into my little tank. Very nasty. I spent several days curled up in there taking it back to bare metal.

My idea of just reaching in....didn't work by a long chalk.

I made sure my wife was there making sure I was conscious.

 

When it was ultra dry...I applied two coats of a Thomson product that said it was for drinking water tanks.

I allowed it uber-time to dry...over a week.

 

This year...my tank is just as bad or worse than it was before !

[dmr]

2 hours ago, Bobbybass said:

My pot of Vactan specifically says...not for potable water tanks.

 

Beware of making sure it is for potable tanks. Some of the bitumen compound is very dangerous.

I ordered a tin for drinking tanks and the supplier substituted a different one,,.which was dangerous.

 

Last year I crawled into my little tank. Very nasty. I spent several days curled up in there taking it back to bare metal.

My idea of just reaching in....didn't work by a long chalk.

I made sure my wife was there making sure I was conscious.

 

When it was ultra dry...I applied two coats of a Thomson product that said it was for drinking water tanks.

I allowed it uber-time to dry...over a week.

 

This year...my tank is just as bad or worse than it was before !

I assume the Thompson stuff is not an epoxy, so after all the effort you put in going to bare metal why did you not use an epoxy?

 

Mine was done about 6 years ago, I really must have a look inside soon, its a job I keep putting off.

 

............Dave

[Bobbybass]

8 hours ago, dmr said:

I assume the Thompson stuff is not an epoxy, so after all the effort you put in going to bare metal why did you not use an epoxy?

 

Mine was done about 6 years ago, I really must have a look inside soon, its a job I keep putting off.

 

............Dave

 

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