Dumb Question; How Much Damage Does Hand Scrubbing Do To Antifoul?

[charliehows]

I get in the water pretty regularly to clean up the prop, but so far I've been a bit reluctant to use the scrubbing broom on the scum on hull areas for fear of scraping off the antifoul and giving them damn crustaceans a better purchase on the hull afterwards - generally the hull areas away from prop/rudder etc are pretty clear of nasties at haulout but everytime i get in the water i want to have at the scum on the hull - whats the thinking on this?

[Stu Jackson]

What kind of paint? Ablative or hard? Divers clean bottoms all the time. You should be able to do so. Too.

[sapient sue]

As Stu said it all depends on the paint. If you scrub ablative paint you won't have much left to keep the critters at bay. That is the way ablative paint works as it it wears away a new surface is exposed. Hard antifoul on the other hand can be scrubbed fairly vigorously. It also depends on where you are located, cooler water versus the tropics and length of time between haul outs as to how hard to scrub. So how long is a piece of string?

Sapient Sue

[MarkJ]

At $330 per gallon for ablative its not a dumb question at all!

I see folks scrubbing away in a cloud of blue or red water. Its crazy unless you want to haul each season and are racing.

Keep the prop clean as you do and let the goobies build up on you antifoul but knock off any barnacles.

Divers clean boat all the time, they are contracted to CLEAN the bottom, they are not contracted to save your antifouling.

My boat takes 3 gallons at $330 per gallon with the idea I have a few extra coats on the leading edges. Thats a lot of money to go rub off with a $1 green kitchen scourer.

[fstbttms]

Less dependent on paint type and more dependent on how foul you've let the bottom become and what you use to remove the fouling growth. People who claim that cleaning your hull is bad for the paint don't know what they are talking about. Sure, if you wail away at the bottom with a scraper or abrasive scrubber, you will damage or remove paint. But gentle cleaning with the proper tools will actually extend the life of your anti fouling paint, not shorten it. Clean your bottom while it can still be done with carpet or a white pad. Don't wait until you have to literally scrape the growth off. In the Bay Area for instance, a quality paint cleaned 6 times per year will perform well for 3+ years and stay relatively clean between services (meaning better performance under both power and sail) to boot.

[a64pilot]

I was under the impression you wanted to clean ablative paint, that that was what kept it working, removing the old paint layer and exposing a fresh one? Of course eventually you have nothing left if you keep removing it

[fstbttms]

Originally Posted by a64pilot

I was under the impression you wanted to clean ablative paint, that that was what kept it working, removing the old paint layer and exposing a fresh one? Of course eventually you have nothing left if you keep removing it

If your bottom gets foul, it needs to be cleaned regardless of what type of anti fouling is on it. Ablatives are no exception.

[a64pilot]

OK stupid question, but if hard paint worked well, then it would last for years, as in much longer than abalative?
I only have experience with ablative

[fstbttms]

Ablatives do tend to be somewhat shorter-lived than hard paints. This is due to the way they work, which is by "ablating" away (much like a bar of soap) as the boat moves thru the water. That said, with any paint, once the biocide is depleted, the paint becomes ineffective. This typically occurs after 2-3 years, depending on biocide leach rate etc.

[charliehows]

ablative. temperate zone. I get barnacles in the area around the skeg,prop and rudder but relatively few elsewhere - my main concern is, yes, wiping off the $100's of antifoul that i so laboriously applied at haulout.

[MarkJ]

Originally Posted by charliehows

I get barnacles in the area around the skeg,prop and rudder but relatively few elsewhere - .

Yeah, I'd just gently tap them off.

Any slime is going to come off when you go for a sail as the paint ablates, or its not going to slow you down much anyway. Slime may even speed you up


If you are racing its maybe a different story, but for cruising the slime wont hurt but the barnacles may slow you a bit. Coral will slow you a lot so when you start getting that you know its time for a haulout.