Painting a narrowboat water-tank

Painting a narrowboat water-tank

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** Update 27th July, 2018.**

After coating with Vactan
After coating with Vactan

During last summer, the heat of the sun on the hull and the cool of the interior of the water-tank caused a lot of the coating, previously discussed in this post, to flake off.

This left flakes of toxic residue in my water and made it unsuitable as a potable water source.

As an alternative to climbing into the water-tank and getting myself covered in toxic bitumen water-tank paint in the blazing hot summer sun, I decided to try another suggested solution for the coating of watertanks on narrowboats, that would be VACTAN.


A water based product. Instead of bitumen, it applies a latex anti-corrosive coat to the watertank.

The advantages of VACTAN vs Rylards Water-tank coating

Preparation Remove lose materials and residues Remove lose materials and residues
Number of coats 1 2
Time between coats 1hr 8hr
Drying time 1hr 7days
Type Water based Bitumen based
Datasheet Datasheet

Below, there are 5 steps to coating your water-tank.

To amend that.

  1. Strip the loose and decayed metal (#1)
  2. Apply VACTAN (#4)
  3. Flush the residue (#5)

If you decide to use one of the other coatings, then you need to take the steps below.

I’ve made a short video about my experience in applying VACTAN and some of the practical observations about using the product.

Painting a narrowboat water-tank, old version

This little story is about how to paint a narrowboat water-tank:

There’s 5 steps

  1. Strip the loose and decayed metal
  2. Work surfaces down to bare metal or non-corroded paint
  3. Apply Iron Oxide paint to areas still rusting
  4. Apply bitumen blacking paint
  5. Remove paint residue


Stripping and prepping (rusty tank) – 2days
Painting (1 primer and 1 top) – 2 days

Total – 4-5 Days

*This is doing it fast. If you want to paint the tank in two halves it’s going to add a day.


Paint – £15-£20
Brushes – £15 -£20

Total – £40

Step #1:Strip loose and decayed metal


Shave-hook – Triangular headed scraper

Triangular headed scraper
Triangular headed scraper

Water pump

rule il280p pump
rule il280p pump


Narrowboat watertank rust
Removed a few shovel-fulls of rust.

Located right at the front of the boat, the water-tank has been rusting for a while. The paint has come off over time leading to corrosion and a build up of sediment at the bottom of the tank.

Using the triangular headed scraper, or shave-hook, (as it’s officially known), I stripped the inner tank of any of this loose material.

There was perhaps 3kg.

I also had to DRY THE TANK OUT and remove ALL OF THE WATER.

This I did with some sponges, then left it to dry.

Rusted narrowboat water tank
A rusty water-tank

Step #2: Work surfaces down to bare metal or non-corroded paint

Narrowboat watertank
Preparing watertank for painting


Small wire brushes

Small wire brushes
Small wire brushes

Bosch PSB 680 Compact Drill

Bosch PSB 680 compact drill

Crimped wire brushes

Crimped wire brush
Crimped wire brush

Mask + Goggles + Plugs


Actually getting down into the tank.

Ensuring that all the rust is removed from the seems, where the welds are made.

All areas where the paint has come off is reduced to bare metal.

This took a period of about 9 hours in total.

It’s no small job.

You will find you and your tools are covered in sticky grime, I would recommend covering up, I’ve featured the bare minimum of PPE you’re going to require.

Step #3: Apply Iron Oxide paint to areas still rusting

Red oxide coating watertank
Red oxide coating watertank


Iron oxide paint

Iron oxide primer
Iron oxide primer

Getting back into the tank.

Vacuum out with a small handheld 12v Bosch vac, I also wiped the walls down with a damp cloth.

The red oxide is essential to prevent further corrosion. Don’t use any other type of primer.

Priming the area where metal is showing.

Takes about 2-3 hours.

Step #4: Apply bitumen blacking paint

Blacking narrowboat watertank
Blacking narrowboat watertank


Rylard watertank coating.

The regulations concerning water-tank paint coating have changed…

Into the future, all bitumen based coatings are to be phased out.

If you have bitumen ALREADY in your tank, this is the only coating you can apply under current EU health regulations.

Narrowboat watertank coating
Rylard watertank coating

Climbing into the  tank with a large 4″ paintbrush.

I actually poured the paint into an old Fray Bentos pie tin, something you may or may not have lying around….

Initially, I would have said 1-2 hours, but to get full coverage. Working into all the pits and seems. Takes about 4 hours.

I’ve applied two coats.

The best way, if you’re not able to do it in one go,which will involve some physically demanding work, would be to paint one half, leave to dry, then paint the other.

You need two coats. One will not do.

Step #5: Clean residue.

This isn’t one I expected.

There is, however, a fair amount of small paint particles and residue that need to be removed before the water is drinkable.

Simply a case of filling the water tank, mopping down all the sides with a clean mop.

Emptying leaves the particles on the side of the tank which can then be wiped off with a damp towel.

You can use Milton solution.

You may have to do this routinely, if you want to use your water tank for potable water.

Leaving the milton solution to soak for the recommended period, 4 hours, then emptying the tank after flushing round your system thoroughly.

Job done….


10 thoughts on “Painting a narrowboat water-tank

  1. Oh my you have been busy. The water tank look a million times better…..very pleased g. I guess they managed to fix the disel leak in the pipe when they serviced her.
    We’ll done

  2. Wow…..impressive you will have an excellent water tank good for years…..good piece of work….

  3. I have just caught up with your blog.

    This entry looks good, and the tanks itself certainly did, yesterday. I only glimpsed into the gas compartment when you showed me it a couple of weeks back, but that looks an interesting challenge, with it being so much smaller.

  4. After our chat about painting yesterday I had a bit of a read around. Just out of interest, then, here are three pages (probably of many) that might help us all get our thoughts together before August. And I see that there are quite a few courses on painting narrowbaots, would you believe!
    see Bondi Blue –

    Did my Trip Advisor entry on the Middle Bell just now.

  5. I am worried by your use of what you call “Iron Oxide” paint. Red Lead is NOT Iron Oxide – it is Lead Oxide and very definitely should not be used in a potable water tank.

    1. It’s a good job I can read then David, ‘cos it pretty clearly says ‘Iron Oxide’ on the label. Not lead Oxide.
      Thanks for taking the time to comment.

  6. Thanks for you useful guide.
    Very helpful for us. We’ve just bought our 1st narrow boat and the 1st job is the water tank. What a gruelling job.

  7. Thanks very much for pointing me at Vactan. I paid to have the lid removed (it was seized solid) tank cleaned and loose rust removed, expensive job but no doubt very messy, so well worth it. Then I painted the inside of the tank with Vactan and it seems really good. How well it will wear, I don’t know but at least I can remove the lid and have a look in a year or two.

    1. John. I don’t think it lasts forever. I didn’t remove the previous coat of bitumen based rubbish, and it’s this that appears to be coming lose. It’s getting on for 18 months. I will give it another coat when the weather improves.

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