Replacing original steel water tank with a flexible tank

[little-wren]

Hi all!

 

Might I draw on your collective wisdom please.

 

So, this is the current state of my water tank in the bow, I have a plastic tank I use in the galley for drinking and cooking.

 

I've bought a flexible tank roughly the same size and my current plan is to fit this into the bow tank space.

 

I was going to dry the tank out fully, then do a wire brush and I have a can of bitumen type paint (specifically for potable water spaces) to apply.

 

I'd love to insulate the space too, I have some underfloor insulation (the silver type) which I thought would help protect the flexi tank too?

 

In terms of attaching to the pump, any tips? The outlet for the flexi tank is 12mm, I'm guessing some blue hose and a clip will be okay?

 

I surely don't mind a bodge but wondered if there was a neat solution to connecting these through the stop, the filter and into the pump?

 

Thanks everyone in advance, all help gratefully received!

 

EDIT: Images do not seem to be rendering correctly, but it's a rusty-ish tank attaching to a shurflo type pump:)

 

 

 

 

 

 

Edited March 31, 2022 by little-wren
images not rendering correctly

[Mad Harold]

I had a plastic bladder type tank in my old narrowboat.

I assume the original water tank had corroded away and a previous owner had replaced it with a plastic one.

The inner wall of the original tank had been cut away and the plastic one inserted into the space.

As most off the peg pillow type plastic tanks are rectangular, the capacity will be reduced (mine held about 20 gallons)

A triangular one would I think have to be made to order.

Fitting one should be easy as they collapse to quite a small size so should go into your tank hatch easily.

[Alan de Enfield]

47 minutes ago, Mad Harold said:

A triangular one would I think have to be made to order.

 

Traingular ones are readily available at Marine Chandleries as this is what yachts and GRP cruisers use in the bow cabin under the 'bunks'.

Whether the sizes would be suitable I've no idea.

 

Plastimo Flexible Fresh Water Tank 120Ltr Triangular - TCS Chandlery Ltd

 

Vetus Flexible Water Tank Triangular 100 litre (Vetus TANKW1003) (vetus-shop.com)

 

 

[BEngo]

A flexible tank really needs to be hung from its upper edges.  If not, as the tank empties and  collapses it tends to fold in the same places every time. This causes creases, which lead to tank failure and leaks.

If it is hung from the top it does not fold up, so it lasts longer.  This is often not easy to do in a retro fit.

 

N

[blackrose]

I can't see the pictures on my phone for some reason, but if you're fitting a flexible tank liner you still need to scurf out the rust and paint the space before fitting insulation to avoid condensation continuing to corrode the steel. My feeling is that by the time you've done all that you may as well just slap some bitumen on, wait for it to dry and fill it with water.

 

Better still paint it with a water potable epoxy.

[blackrose]

2 hours ago, BEngo said:

A flexible tank really needs to be hung from its upper edges.  If not, as the tank empties and  collapses it tends to fold in the same places every time. This causes creases, which lead to tank failure and leaks.

If it is hung from the top it does not fold up, so it lasts longer.  This is often not easy to do in a retro fit.

 

N

 

Yes they do seem to fail within a suboptimal time period.