20 antifouling paints tested in 13 UK locations: which works best where you keep your boat?
Previous tests have focused solely on one location, but as fouling conditions vary greatly between ports and harbours around the coast, we reasoned it would be of far more use to boat owners around the country if they could draw on some test results closer to home when choosing their antifouling paint from the bewildering range of options out there.
We spent two weeks painting our plywood test panels, in the process consuming 350m of masking tape, 15lt of primer and 40 (cheap) paintbrushes, not to mention the 20 antifouling paints themselves. And now, seven months and 4,400 miles of driving later, here are the results of our round-Britain antifouling test.
How we tested them
We primed our 26 test panels with International’s Interprotect Epoxy Primer before using a tie-coat primer where required and applying each of our antifoulings with the recommended number of coats (two, in most cases). We applied the paints in strips, with an 11mm unpainted strip between each paint, acting as a control surface.
We restricted the test to single-pot eroding paints in blue: these are the most popular antifoulings for cruising boats. With the paint dry, we loaded the boards into a trailer and drove them round the country, installing them facing the sun where possible and aligned with a modest tidal flow to simulate their normal usage as much as possible. We installed the boards in late March, returning in early October to remove them and inspect the results.
There were big differences between paints on the boards in terms of the amount of fouling they retained. What was telling was that even the worst-performing paints showed a massive improvement over the unprotected control surfaces – so even a cheap paint is better than nothing. However, the best performers were in a league of their own: read on to find out which paint you should choose.
Do you need antifouling?
We left the backs of our test boards as bare primer to act as a control. The good news is that without exception, every antifouling paint showed a marked improvement compared to the bare panels. Fouling differed in a big way between each of our 13 locations, from Dunstaffnage, which had minimal growth, to Hamble, which showed by far the worst. Lowestoft and Waldringfield, on the East Coast, were also bad. Whitby and Inverkip had very heavy slime, while Neyland and Caernarfon saw moderate shell and weed growth.
How the panels looked after more than six months at sea…