Hard Antifoul

[Aege]

I have a moderately used Etap21i. When purchased, it had been antifouled with Hempel hard racing, which I have continued to use for each of the last four years, overpainting the previous years. I've been pretty happy with its performance.

It now has several years worth of layers, but is still in pretty good nick. Do you think I need to antifoul it again this year, or would a quick rub-down with wet and dry be sufficient?

Thanks.

 

[Pasarell]

Almost certainly yes I'm afraid. Hard antifouling works by releasing biocide from a non soluble paint resin matrix. As the paint ages it becomes like a honeycomb structure with the holes resulting from biocide release. The antifouling becomes less effective as the biocide has to work its way up from deeper in the paint film. Overcoating pretty much seals off the previous years material even if there is biocide left in it so you have no cumulative effect from the biocide. Further bad news is that the underlying paint film that you overcoat is severely weakened by the loss of its structure so there will come a time, soon, when it will start to crumble away from the hull surface under the weight of new material painted over the top.

 

[pvb]

As Pasarell has said, you do need to re-antifoul. But there's no need to use hard antifoul on your boat. If you change to an eroding antifoul, there'll be much less paint build-up on the hull in future - putting off the day when you've got to strip it all back to the gelcoat.

 

[Aege]

As Pasarell has said, you do need to re-antifoul. But there's no need to use hard antifoul on your boat. If you change to an eroding antifoul, there'll be much less paint build-up on the hull in future - putting off the day when you've got to strip it all back to the gelcoat.

Thank you chaps - that's really useful (but disappointing!). On the bright side, at least I can use eroding antifoul this year and save a lot of money!

Aege

 

[pagoda]

Thank you chaps - that's really useful (but disappointing!). On the bright side, at least I can use eroding antifoul this year and save a lot of money!

Aege

I inherited a similar set up with our boat. I feel that the harder AF is a thinner layer than the eroding AF i've used in the past. The eroding AF is certainly easier to remove when needed, but it also comes off in clouds if you clean up the waterline during the season. Pluses and minus in all cases.

 

[pvb]

The eroding AF is certainly easier to remove when needed, but it also comes off in clouds if you clean up the waterline during the season.

Always best to do an extra coat around the waterline. I use Micron eroding antifoul, which lasts for 2 years in the water. When I lift the boat to antifoul again, most of the remaining old stuff rubs off easily with a Scotchbrite pad used with a running hose, thereby minimising paint build-up on the hull.

 

[LONG_KEELER]

I have used Hempel Hard Racing for some time now and find it ok for the East Coast.

During the season, I scrub using a Scrubbis regularly from a marina berth which has been a revelation . When I come out, the bottom is invariably clean.

This method works for me but I can appreciate that everybody has different plans of attack.

With the eroding root, I just used to scrub away all the antifouling which is becoming weaker due to the lessening of biocides.