How Long Does Antifouling Lasts

[Andrewcook]

How long does Antifoul last underneath Boats is it every Two Years or Five Years if and when does that needs to be done? And what type of Antifoul the best one to use for the Job? 

[Vaughan]

Depends if it is a hard or soft antifouling.  If your boat spends most of the time on a mooring then choose a soft one, but it will need re-painting more often.

How often?  A matter of forum opinion!

I suggest not more than 3 years, and change the anodes at the same time.

[ExSurveyor]

I go five years and combine it with a survey. I don't have any anodes, they have never been fitted from new, no sign of problems on the last 3 surveys. I do moor on the river frontage.

[Smoggy]

It largely depends where you moor as well, different water chemistry supports different growth, for well inland with mostly fresh water a quick coat around the waterline where the light gets (mostly for aesthetics) will probably suffice, if on salty water growth can be a bit more determined to hang on, change area often enough and a lot will die and drop off as it can't cope with the different water conditions.

I just chucked a quick coat under mine which was last done in early 2019 and after a pressure wash it was fairly clean, I didn't see it when it was lifted so can't comment, I use a cheapy claimed up to 40 knots antifoul (semi-hard, https://premiermarinepaints.co.uk/antifouling/semi-hard-antifouling-paint) with next to no preparation (wire brush off loose bits and slop it on), I know a guy who spent a fortune on fancy stuff with all the primers from bare gelcoat and it fell off in sheets first time he opened it up in the wash..

In short, how long is a piece of string?

[annv]

Hi I use Jotans and recon on four years when i used Blakes only one years BUT i did have it lifted, pressure washed and chocked on the bank every year it was cheaper and easier to apply. John

[Cal]

We used the Premier Paints semi hard antifoul on our last boat and it was always fairly good. That said they did hike the price up a few years back quite substantially.

The last few years that we had the boat we tended to bring it out of the water every winter for a few months so we found we were repainting it every year just to tidy it up more than anything. It didn't really need a fresh coat but we might as well do it while it was out of the water.

[Heron]

Judging by the hire yards standards, one coat lasts many years! First boat I bought the surveyor said do not bother.

If you must take the boat out of the water in the winter, remember that if you have bubbles, freezing weather might burst them making the situation worse.

[Vaughan]

38 minutes ago, Heron said:

First boat I bought the surveyor said do not bother.

For a Fibreglass boat on the Broads, he was quite right!

[Smoggy]

When I had an inland only boat on fresh water I would get the smallest/cheapest tin and do around the waterline first then work under till it ran out, the bits that didn't get done stayed with whatever was there, it was just a pretty up excercise.

The main thing is to jetwash as soon as the boat is lifted and all inland crud will just drop off, leave it to dry and it will take a major scraping excercise as it sets like concrete, if the boat is being lifted while you're not there it's well worth paying the yard extra to jetwash.

[andyg]

One particular hire yard seem to apply it with trowel lol. I always thought on grp boats it's more a cosmetic feature more then anything else. 

[Oddfellow]

2 hours ago, Heron said:

Judging by the hire yards standards, one coat lasts many years! First boat I bought the surveyor said do not bother.

 

I take exception to this statement. You can't tar them all with the same brush, but you can tar the bottom of a cruiser and, it can be very effective as a barrier. I have applied black tar varnish to a few boats in my time. One Bounty that came through my yard was in the worst condition I had ever seen. The bottom was more pockmarked than an acne-ridden  teenage boy who was suffering from a dose of bubonic plague. It was a ticking timebomb but the owners needed it protecting as much as it could be for as little as possible. Black tar varnish was the only option. 

Antifoul can last a long time and it's never just one coat. I suspect most Broads yards use a self-erroding antifoul which will probably do two, maybe three seasons underwater whilst the wind and waterline will likely need doing rather more often. Absolute Freedom (now TideWay) was a Broom-built craft that has a coppercoat and though requires no antifoul. It kept it in very good order for a boat built nearly 30 years ago. 

Bridgecraft does a stunning job of winter maintenance each year on its fleet and I can't believe their boats go much more than a season without a recoat. 

[Cal]

13 hours ago, andyg said:

One particular hire yard seem to apply it with trowel lol. I always thought on grp boats it's more a cosmetic feature more then anything else. 

Depends where you are based. In Burton Waters, Lincoln zebra mussels were very prolific and if your antifoul was a bit older and less effective then it would grow a lovely mussel beard which depending on the power of the boat could have a very detrimental effect on the performance and fuel economy.

[Smoggy]

Zebra muscles were a PITA on the gt.ouse, a right sod to pick out from outboard motors and prone to getting into water intakes when tiny and growing causing blockages it not regularly used.

[BroadAmbition]

All our paints and varnishes etc come from Marine Industrial at Worstead.

On the hull after jet washing then hand scrubbing with a green nylon pad, washed off any areas that are down to the wood or any replaced planking is treated to Five star Cuprinol, then a 011 underwater primer, followed by 037 Coastal anti fouling at least two coats (Red) than a hard 011 Emperor blue for the boot topping, again two coats.

Every two years the above process is repeated, However we missed this year due to the Covid issue so for the first time since 2007, April 2022 it'll be three years, It'll be interesting to see how it has held up

Griff