TRIED & TESTED


No need to repaint: Pixie was returned to the water after a spray-off


‘It took less than five minutes to pressure wash the hull, which would normally take 20 minutes’


– but it wasn’t. There was a light covering of green-brown slime in places, as usual. However, comparing


photographs, I found that there was a clear reduction in the amount of slime around her hull, rudder, prop shaft and bow compared to the previous year. Last year, there was a thick covering of slime. This year, it was much lighter and appeared to lack adhesion, easily removed by wiping a finger or sponge across the hull. ‘This is just what we expect,’ explained Nick Griffin from Ultrasonic Antifouling. Once I got over the initial appearance, I could see Nick’s point. It took less than five minutes to pressure wash the whole hull, which would normally take about 20 minutes. Yes, there was slime, but not a great deal and it washed off easily.


Antifoul paint I had deliberately left exposed


patches of old antifouling paint when I applied the fresh coat back in March, and these were no more heavily fouled than the rest of the hull. However, a test patch of topside paint on Pixie’s keel revealed a thin layer of green weed that was harder to remove. So although Ultrasonic Antifouling doesn’t do away with the need for antifoul paint, it does seem to remove the need to apply a fresh coat every year. There was some weed growth on the top of the rudder and on


Test conditions The difference is clear – but is it all down to Ultrasonic Antifouling?


Pixie’s hefty skeg, but this came off with little effort. Unlike the previous year, her prop was now free of barnacles and weed, but we motored a lot more this season. Like most yachts in her marina,


Pixie grew a short green beard of weed at the waterline, but hers could be removed with a swipe of a finger. Watching other boats being hauled out, it was clear that


Pixie had suffered less fouling than most, but as the hoist operator observed, ‘every boat is different’. We sailed far more than usual


in 2010 and cruised much further afield, so I can’t be completely sure that the perceived reduction in fouling was entirely down to Ultrasonic Antifouling. I don’t see it as a replacement for traditional antifouling paint, but it seems to have improved the paint’s performance. The difference seems impressive, and not having to spend the first 10 minutes of every trip lying upside-down in the forecabin cleaning the log impeller is a big bonus. W


Most weed and slime came off easily, with a swipe of a finger


The Ultra DC 10 unit, as tested, costs £949 (inc 17.5% VAT, ex- installation). Tel: 01202 606185, www.ultrasonic-antifouling.com


The performance of any antifouling system will vary from port to port and from year to year. Variables such as sunshine and tidal flow also have an effect, so it’s nigh-on impossible to conduct a rigorous, conclusive, scientific test on a real boat in the real world. The following factors may have affected our results: In 2009, Pixie had a marina berth in Portsmouth Harbour. We sailed mostly at weekends and logged about 1,000 miles, cruising the English Channel. In 2010, we took a sabbatical from work and sailed 1,600 miles: west from the Solent, up the Irish Sea, round the top of Scotland and back through the Caledonian Canal to a marina on the Clyde. In 2009, Pixie was


antifouled with Blakes Tiger Xtra. In 2010, we used Hempel Tiger Xtra and Ultrasonic Antifoul.


Why you still need antifoul paint Ultrasonic Antifouling’s director, David Sothcott, says: ‘Traditional antifoul is still a good idea. First, a dark colour on the hull helps to reduce light, which helps to reduce growth. Secondly, an unpainted hull will very quickly stain with all the pollutants in the water.’


Antifoul paint only


Antifoul paint + ultrasonic


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