Kerry and Fraser Buchanan install a UV light water filtration system to make the tank water stored on their Barbican 33 more palatable

Bought in 2018, Barberry is our 1984 Maurice Griffith-designed Barbican 33 and we’re only her third owners.

When she came to us she was in beautiful condition and had been lovingly maintained by her previous owners, who’d sailed her for 18 years.

However, she’d been out of the water for three or more years, and her systems were all quite dated.

A boat moored net to a pontoon

Barberry is bound for the Mediterranean. Credit: Kerry Buchanan

Since we bought her we’ve been gradually updating her and adding some extra creature comforts, as we intend to sail her from her home port in Bangor, County Down, to the Mediterranean via the French inland waterways.

We’ve been dreaming of this trip for decades, and Barberry, with her 1.2m draught long keel, should be well suited for both the open water and inland waterways elements of the voyage.

The challenge

Fraser has increased our water storage from 100lt to close to 300lt, not counting any barrels we might choose to carry on deck, but the water from the taps still tasted unpleasant, despite new tanks, filters, and renewing all the water pipes.

On our shorter cruises, we have tended to use bottled water for drinking and only used our onboard water for the kettle, washing up, etc.

However, we hate the plastic waste this creates, and challenges faced when disposing of plastic, so we have been looking for an alternative.

The obvious answer was a watermaker, but at around £3,000-£5,000 that would be out of our budget.

Plus, the extra power consumption would mean we’d have to bump up our solar systems and maybe look at a generator, for which we have neither the budget nor the space.

A man drinking from a green glass

Fraser braves a treated tank water taste test. Credit: Kerry Buchanan

And watermakers do take up a fair amount of space, even the compact models.

Barberry is old-school. She’s of slim build for her length (unlike me), and doesn’t have the capacious stowage of a modern day cruising boat.

I should mention here that Fraser gets quite stressed by plumbing, whether it’s household plumbing or boat related.

He goes a bit wobbly at the thought of electrics too, and I’m little use to him due to my arthritic joints, so we’re always looking for a solution to a problem that can be fitted by a grumpy amateur without too much cussing.

Making water drinkable

After some online research, we decided on the Acuva ArrowMAX 2.0 disinfection system or UV light water treatment system, which inactivates 99.999% of E. coli bacteria.

It comes with an advanced pre-filter, removing 99% of chlorine and lead, plus volatile organic compounds (VOCs) and unpleasant odours.

When it came to ordering the UV unit, I could only find three options: direct from the manufacturers in the US, with high postage costs and a long wait, not to mention unpredictable customs tax fees on arrival in the UK; the second company was a well-known online UK chandler, which is what we opted for, and the third was another UK company that seemed to be selling it for almost double the price.

A sink on a yacht

The sink before installation of the new Acuva tap. Credit: Kerry Buchanan

The kit comes with an advanced filter that can apparently handle up to 5,678 litres before needing to be changed, according to the manufacturer (a round number of 1,500 US gallons!).

There is also the UV unit, which is a neat gold-coloured box measuring approximately 25cm x 10.5cm x 4.75cm.

The Smart Tap has a self-cleaning facility, and there are various clips, sections of hose, power supply and wiring, etc.

The rather fancy looking brushed nickel tap lights up blue to show when bugs are being zapped as they pass through the UV light.

The whole thing reminded me of a garden pond setup we’d had many years ago, but much neater and higher tech.

Cost comparison

 Katadyn Power Survivor 40E watermaker

The Katadyn Power Survivor 40E was another option

The Katadyn Power Survivor 40E is a watermaker model we considered for our 32ft 8in boat and the manufacturers claim it’s the smallest one around.

  • A new unit costs approximately £4,000
  • Output is 6 litres per hour
  • Power consumption is 4A per hour
  • It measures 44.5 x 40.5 x 15.2 cm plus a prefilter which measures 30 x 15 cm
  • Manufacturer’s manual states that with reasonable care and maintenance, it can be expected to provide ‘years of useful service’

Acuva ArrowMAX 2.0

Acuva ArrowMAX 2.0 diagram

Acuva ArrowMAX 2.0 diagram

  • The unit costs £599 (£610.90 including delivery to Northern Ireland)
  • Output is 120 litres per hour (at least until the water tanks are empty).
  • Power consumption is 9W when active (0.1W on standby), equating to an almost negligible 0.75A per hour in use when run on 12V DC. This doesn’t include the power used to run the boat’s actual water pump, a Jabsco ParMax 2, but the water maker also requires the same pump to be run to get at your lovely, clean drinking water, so no power savings to be made there.
  • The dimensions are:
  • 25 x 10.5 x 4.75 cm (UV unit)
  • 28cm tall with an additional 11cm beneath the counter for tap, with a 12cm reach for pouring.
  • 25cm x 5cm for the filter cartridge
  • Manufacturers claim a life expectancy of 7+ years.

Buying bottled water

Bottled water

Reducing the amount of plastic waste is a benefit. Credit: Angela Bragato/Alamy

If we drink 2lt each every day (more in hot climates or when hungover), and the current supermarket price of bottled still water is approximately 40p per litre, based on a six pack of 1.5lt bottles from a UK supermarket chain, then costs are:

  • For one year, approximately £584, roughly the cost of the Acuva UV unit. Over seven years, just over £4,000, roughly the cost of the watermaker.
  • Power consumption is measured slightly differently from the above. In sweaty man/woman hours lugging dozens of bottles along decaying jetties, wrangling them aboard, manhandling them down the companionway, and finally stuffing them into every nook and cranny we can find in the low down bits of the boat (because who wants all that weight high up?), the power drain equates to at least one expensive bottle of wine and a large bar of chocolate per trip to the local shop.
  • Dimensionally, bottled water takes up far more space in the boat than either a watermaker or a UV steriliser. Factor in the curses as a floorboard clatters onto your toe as your try to extract the last bottle, the one that rolled to fingertip reach in the bilges, and the case for the defence of bottled water will metaphorically wash its hands and walk away. And don’t forget the added smugness that comes from not adding to the environmental problem of plastic waste. The downside is that we’ll still be limited by the amount of water we can carry in our tanks and on deck, so we’ll have to find water supplies more frequently than those cruisers lucky enough to own a watermaker, but this seems a good first step towards self-sufficiency.

The downside of a UV light water filtration system

Replacement filters for the Acuva don’t seem easy to find, and I’m a little concerned that we might end up having to order them directly from the manufacturer, unless other compatible filters can be used instead.

They cost $50 (around £47) from Acuva, plus shipping costs.

Materials and tools used

Two short sections of PE-X pipe to act as hose tails for the T-piece Hose clips x4 to secure the blue water piping over the hose tails New T-piece as US fittings didn’t play well with UK pipes

  • Cordless drill with bits for drilling smaller holes for electrical wiring, and also core drill and bits to create the hole for the tap
  • Two short sections of PE-X pipe to act as hose tails for the T-piece
  • Hose clips x4 to secure the blue water piping over the hose tails
  • New T-piece as US fittings didn’t play well with UK pipes
  • Old towels to soak up the inevitable spillages
  • Plastic pipe cutter

Fitting the UV light water filtration system

Under the sink on a yacht

Credit: Kerry Buchanan

1. We emptied the under-sink cupboard so Fraser could decide the best place to mount the UV unit and filter, and where to run the plumbing and electrics.

At the same time, we decided where to site the tap.

contents from under a sink

Credit: Kerry Buchanan

Part of that decision was influenced by the shape of our galley sink (round), meaning the tap had to be in a position where its curved spout would pour water into the sink and not over the very limited work surface.

A sink on a yacht

Credit: Kerry Buchanan

2. We decided to keep the existing hand-pump, which delivers filtered water that doesn’t taste very nice, as a back-up means of getting at our water supply in case of electrical failure or pump failure.

Fraser drilled a pilot hole for the Smart Faucet next to it.

a small hole drilled next to a tap on a sink

Credit: Kerry Buchanan

After drilling the pilot hole and then core-drilling a ¾in hole, the tap was dry fitted to make sure everything worked and that we could still use the existing taps.

A filter on a boat for a UV light water filtration unit

Credit: Kerry Buchanan

3. The filter is the only part that will need to be changed so it had to be accessible.

Fraser fitted it low down at the front of the cupboard for easy access, but left enough room for connection to the T-piece fitting that would be inserted into our cold-water piping.

This has an on/off valve, so that also needed to be accessible.

The filter connected to a UV light water filtration system

Credit: Kerry Buchanan

A point to note when fitting one of these is that even after you’ve drained your system some water is likely to remain in the pipework.

The instructions warn that this will happen, so don’t be too surprised if you get wet feet.

A UV light water filtration unit installed on a boat

Credit: Kerry Buchanan

4. The UV unit should never really need to be touched, and as that’s probably the expensive bit, Fraser sited it high up at the back of the cupboard where it’s less likely to get knocked when we stuff everything back inside.


A UV light water filtration system in place on a boat

Credit: Kerry Buchanan

There are also two electrical wires that plug into this unit, so Fraser made sure they were secured to the bulkhead to prevent them from being accidentally tugged free.

A man cutting tubing on a boat

Credit: Kerry Buchanan

5. Cut the ¼in white tubing provided to the correct length to fit between the filter and the UV unit, and then a shorter piece to fit between the filter and the T-piece.

These are all push-fittings, and easily locked in. It can take considerable force to lock these fittings into place securely as you push the pipe past the O-ring.

Then more tubing was cut to length to join the underside of the tap to the UV unit via the flow restrictor.

Again, these are easy push fittings, but can be a potential source of a leak if you’re trying to do this in a restricted space, as Fraser was.

Make sure they’re pushed firmly all the way home.

Wiring being run from a sink to a UV light water filtration system

6. Running the wiring was surprisingly trouble-free, and Fraser was able to run the DC power supply wire across the back of the engine bay to the negative bus bar and the fused switch panel.

The only hitch was that the length of wire provided was a little short, so he had to extend it.

Barberry is only 10m in length, so bigger boats might find the wires need considerable extension to fit.

The other short section of wire runs from the tap to a connector on the UV unit – we assume this only functions to make the tap glow blue every time it’s used, but that could be an over-simplification.

A t-piece fitting on a boat

Credit: Kerry Buchanan

7. Leak testing reminded Fraser why he hates plumbing so much.

The T-piece fitting leaked because it turns out that 15mm is slightly less than ½in.

The US kit supplied was measured in inches, but the tubing and pipework on the boat is all metric, and they’re not directly compatible.

It might have been possible to use two beefier O-rings inside the T-piece, but instead, Fraser decided to order a new one that can cope with the UK pipe diameter without throwing a hissy fit.

He’d have preferred to find a T-piece with hose tails for a more elegant and secure fit, but wasn’t able to source one.

The one he bought has 15mm inlet and outlet (the arms of the T) with a ¼in push-fit outlet to attach to the filter tubing (the stalk of the T).

T-pieces and piping for fitting a UV light water filtration system

Credit: Kerry Buchanan

8. Finally, everything was fitted together and a second leak test was carried out.

This time, the leak came from the push fitting on the flow regulator.

When he was fitting this, Fraser had pushed it into place firmly, but it was in an awkward place to reach (boat yoga), and he’d not quite pushed it past the O-ring.

Once that was sorted, the tap worked perfectly.

A tap lit up as part of a UV light water filtration system

Credit: Kerry Buchanan

9. The tap lit up as expected, telling us that bugs were being zapped and chemicals were being removed from our drinking water.

Now it was time to test the water.

Was it going to taste better than the water from our hand-pumped tap that only went through a normal water filter?

It was a success. The water was running from the post-winter dregs of our mostly-drained tanks, yet it still tasted great.

No plasticky flavours, nothing to object to.

It was a huge relief to know that we haven’t wasted all that money, not to mention the time and effort to fit the thing.

Tail ends

Most boat systems use flexible pipe for their water supply, unlike the more rigid pipes used in domestic settings.

The stiff piping is more easily compatible with push-fit fittings like those provided, but it doesn’t really work for the flexible hoses we have on Barberry, hence the Heath Robinson hose-tails made from stiff domestic tubing (inset photo above).

If you have stiffer piping on your boat, this need not be an issue.

  • Before finding a work-around for the metric/US differences, Fraser tried buying ½in hose end fittings from a well-known online retailer, but they didn’t fit our pipes for some reason. He also tried taking the fittings along to a respected plumbing supplier for advice, but the knowledgeable man behind the counter said he’d never seen fittings like it in his life and was unable to offer a solution.
  • The only other question left to us at the end of this boat job was, where on earth was the little round washer supposed to go? This was the only bit left of the supplied parts that came with the unit, but wasn’t mentioned anywhere in the instructions and the system works perfectly without it. We’d be keen to hear from anyone else who has fitted one of these, if they can answer that question for us!

End note

Unable to source another Jabsco pump, we purchased a Whale Watermaster automatic pump as a spare.

It’s now several months since we fitted the UV light water filtration system, and it has more than paid for itself in terms of safe, delicious water.

Continues below…

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We’re currently near the south of France and have been drinking boat water from the fancy blue tap for almost three months of extended cruising.

The water has remained excellent quality, and we’ve watched other boaters struggling along jetties with carrier bags full of bottled water with relief, only tinged by a little smugness.

The Acuva ArrowMax 2.0 has so far performed exactly as we hoped.

Enjoyed reading Fitting a UV light water filtration system?

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