Watertank rusting

[Steve Manc]

Hi

I have a narrowboat built by Coalcraft. The watertank is steel not stainless steel. I empty the tank every September, October when I winterise the boat. In April when I wake the boat up the initial water from the tank shows signs of rust. 

The watertank is under the deck and gas locker at the front of the boat 

Has anyone else experience this?

Has anyone got into the watertank to de-rust it and paint it?

Thanks 

Edited June 19, 2023 by Steve Manc
Grammar

[frangar]

You need to open the access hatch. Clean the tank by removing the old paint and getting rid of the rust..usually by scraping and maybe using vactan. Then repaint using either water potable bitumen or a suitable potable water two pack. It’s not a too bad job if you keep on top of it and do it every few years….if you leave it it’s not as much fun. 

[gatekrash]

We do ours fully, 3 coats of potable bitumen every 3 years, but we also patch it every year if we spot it starting to rust.  But we have really good access to our tank so it's not a terrible job (especially as the Mrs is smaller than me and has to get into it 😁 ).

 

Once you've done it you need to leave it for a couple of weeks to dry off then keep filling and flushing it for a couple of weeks as the water starts smelling of bitumen.

 

Edited June 20, 2023 by gatekrash
Add a bit more

[Steve Manc]

Thanks for your replies

[Bod]

10 hours ago, Steve Manc said:

Hi

I have a narrowboat built by Coalcraft. The watertank is steel not stainless steel. I empty the tank every September, October when I winterise the boat. In April when I wake the boat up the initial water from the tank shows signs of rust. 

The watertank is under the deck and gas locker at the front of the boat 

Has anyone else experience this?

Has anyone got into the watertank to de-rust it and paint it?

Thanks 

Done the self same job on our Colecraft.

The access plate is around the filler hole, the screws may be hidden by filler, the panel is big enough to climb through. 20 brass screws 5/16x18 BSW thread. (replaced with M10 csk stainless steel. Thread re-cut to suit.)

I found hand tools were best inside the tank, kept the dust under a little control, others will suggest power tools for speed.

The potable paint took ages to dry, 10-14 days.

Whilst in there be sure to check the dip pipe for internal rust, ours blocked completely and had to be replaced.

Once the access plate screws are exposed, take time to get the correct sized screwdriver, to avoid wrecking the screwheads, if you have BSW screws replacement may be difficult.

[Lily Rose]

3 hours ago, gatekrash said:

We do ours fully, 3 coats of potable bitumen every 3 years, but we also patch it every year if we spot it starting to rust.  But we have really good access to our tank so it's not a terrible job (especially as the Mrs is smaller than me and has to get into it 😁 ).

 

Once you've done it you need to leave it for a couple of weeks to dry off then keep filling and flushing it for a couple of weeks as the water starts smelling of bitumen.

 

 

Blimey, that looks like me about 5 years ago. Happy memories (not).

 

Mine was in a right state when I first did it about 5 or 6 years ago. I got inside and cleaned and de-rusted as best I could then a coat of Vactan followed by two of Black Jack. Horrible job!

 

Last year I decided enough rust was coming back through to be worth doing something again but it was nowhere near as bad as the first time and as I didn't fancy doing the full horrible job again I just emptied it, dried it and gave it a good brushing plus used a wire brush on the obvious rusty bits. After another rinse and dry I just gave it a coat of Vactan, mostly from the outside with a brush taped to a length of wood. After a couple of days drying I gave it another coat, mainly just in case I'd missed any areas. After a couple more days I rinsed it with a hose and removed the rinsing water with my wet and dry vac. Repeated this a couple more times. 

 

That was a much easier job than the first time and a year on is still looking pretty good. If I can get 3 years out of that before needing to repeat it I'll be happy. Even 2 years would do.

 

I expect the water would be fine to drink but we always carry drinking water separately so would only need to do that if we ran out. Hasn't happened yet.

 

Edited June 20, 2023 by Lily Rose

[Steve Manc]

We carry 5 lts bottles of water for drinking and food.

At the end of summer I will open the hatch which is in  the middle of the deck in front of the front doors. 

Thanks for the information and replies 

[Tracy D'arth]

There are many boats 30 years plus old  with integral water tanks that have never been opened, they seem to survive.