When does weed stop growing....

[Mark-1]

I dried the boat out early June and pressure washed it off. Sadly taking large chunks of AF completely off and seemingly reducing the usefulness of the remaining AF.

6 weeks later there is thick weed grown and a substantial covering of barnacles. Far worse than before.

So it certainly needs a second mid season spray off.

HOWEVER, it seems clear I need to apply primer this time - the AF didn't stick well without. Which means I can't just slap a coat of AF on when I next spray it down or I'll be painting primer over badly stuck AF in three months time. (No, I won't be sanding it back to gel coat over winter - life's too short, I'll be trusting that any remaining old AF is secure and priming over the lot. Don't judge me. ?)

So I seem to have got myself in a position where I have a boat that's effectively not antifouled with 3 months of the season left to go.

So:

If I spray it off in a couple of weeks time will I already be out of prime weed/barnacle growth season, to the extent that I can leave it until liftout in Nov?

Do barnacles even have a season where they no longer start to grow? The barnacles bother me more then the weed cos I fear a point where the pressure washer won't shift them and they become time consuming.

Can I apply primer between tides then apply AF the following day between tides?

Should I suck it up and spray it twice in the next three months?

Any other suggestions?

 

[James_Calvert]

If you're using an ablative antifouling, don't pressure wash.

Wipe the fouling off with a sponge. That leaves most of the the antifouling still there to do its work.

 

[Mark-1]

If you're using an ablative antifouling, don't pressure wash.

Wipe the fouling off with a sponge. That leaves most of the the antifouling still there to do its work.

Yes, I've learned three lessons and that is one of them, but that ship has sailed.

The weed and barnacles have to come off and a sponge isn't going to touch it.

 

[James_Calvert]

Yes, I've learned three lessons and that is one of them, but that ship has sailed.

The weed and barnacles have to come off and a sponge isn't going to touch it.

I have a hard boot top, which I try to keep clean during the season with a sponge, maybe using the green scourer side occasionally. We generally lift out in late October by which time it's most likely been left untouched for a month or so. And it generally has a nice beard growing there by then, along with the odd barnacle. So I'd say fouling keeps growing until at least then.

 

[Mister E]

Try scraping the weed and barnacles off rather than pressure washing.

 

[LittleSister]

I've read that it's in the spring and early summer that the 'seeds' of fouling attach to the hull, and also then grow fastest (I can't remember whether that was weed or creatures).

That said I have launched in mid-summer before, and it didn't stop me getting some fouling, but not as bad as a whole season, or even half a whole season.

I've also found that anti-fouling reduces, but doesn't stop fouling.

So, in answer to your question, I would say yes, just pressure wash off now and that will see you through until November if you can tolerate a moderate amount of fouling.

 

[mainsail1]

Coppercoat is the answer. 10+ years of bliss.

 

[Mark-1]

Thanks for the comments so far.

Maybe a slight tangent but there seems no clear idea of when the barnacle larval settlement/recruitment period is. (I know the terminology now!) Some sources say year round, some sources refer to a 'season' but don't state when it is.

Seems that they chuck larvae out in the winter which suggests the things are ready to latch on mainly in summer but nowhere can I find anything explicitly stating that.

Incredible that so little is known about such an abundant creature.

 

[cherod]

and how about the anti fouling between tides, can it be done , is there such an ant foul ? ( my only experience is when the boat is up the slip )

 

[Mark-1]

and how about the anti fouling between tides, can it be done

Yeah, I've done that a lot. Primer on the other hand... I have my doubts.

 

[LouisBrowne]

You might try using a Scrubbis (a buoyant semi hard scraper on on the end of a bent pole). I use hard antifouling and have a go with the Scrubbis once a month or so and I find it quick and effective. Even though you have lost patches of antifouling it might help you to keep growth under control until you lift the boat out for the winter.

 

[jac]

IIRC Growth is related to water temperature - it peaks in August in UK and won't drop too low for growth until at least late October

 

[Mark-1]

Thanks all. Decision made: I'm gonna spray it off, put a coat of AF on without primer and see what happens.

Best case it's fine, worst case is still tolerable.

Would it be immoral to sand the AF off a nearby boat as a control for comparison in autumn?

 

[cherod]

Yeah, I've done that a lot. Primer on the other hand... I have my doubts.

thank you mark ,, any brands / makes / types that you can recommend ?

 

[Daydream believer]

Coppercoat is the answer. 10+ years of bliss.

Yes, I agree. That way you only need to get the boat out every 3 months, jetwash the extensive weed growth & muddy film off & put the boat back without bothering to apply any antifould paint.
Pretty useless otherwise, so you do need to scrape thewaterline weed off every 2 months once it get to 8 inches long.
11 weeks:-

 

[neil_s]

I've just scraped copious barnacles off the bottom of my boat despite upgrading the A/F this season. I favour nosing onto a convenient beach an hour or so before high water and getting over the side in a wetsuit, I have a long handled scraper that saves you having to hold your breath (mostly!)

 

[Mark-1]

thank you mark ,, any brands / makes / types that you can recommend ?

I just buy the cheapest. Flag from F4 the last few years. And no, I don't recommend it. Modern antifoul just doesn't work as well as old-fashioned AF, full stop. ?

 

[Mark-1]

I've just scraped copious barnacles off the bottom of my boat despite upgrading the A/F this season. I favour nosing onto a convenient beach an hour or so before high water and getting over the side in a wetsuit, I have a long handled scraper that saves you having to hold your breath (mostly!)

I have access to a drying beach/hose/pressure washer 100m away from my mooring so it's no drama to wash it off and the kids love the pressure washer as much as they love sailing. I'm less enthusiastic about painting new AF on, but such is life.

 

[cherod]

I just buy the cheapest. Flag from F4 the last few years. And no, I don't recommend it. Modern antifoul just doesn't work as well as old-fashioned AF, full stop. ?

thank you ,, i dont mind doing it every year if it keeps it clean ,,, ( also have jet wash handy etc ) last time i used industrial stuff , it lasted one and a bit years and cost £ 100 ( two hulls )

 

[mainsail1]

Yes, I agree. That way you only need to get the boat out every 3 months, jetwash the extensive weed growth & muddy film off & put the boat back without bothering to apply any antifould paint.
Pretty useless otherwise, so you do need to scrape thewaterline weed off every 2 months once it get to 8 inches long.
11 weeks:-
View attachment 120539

I wonder if you have thoroughly burnished the surface after application has dried to activate the copper coat. I did not do it very well the first time and had the problem you mention.