When to remove antifoul

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picardy

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This may sound like a silly question but my 34 yacht (2007) has numerous layers of antifoul (6-8) in my 3 years of ownership alone.

It is in good shape and i tend to sand it each year with 80grit fully wetted with a hose to remove roughness and provide a key for new coats.

Is there a recommended max number of coats before it should all come off?

Thanks
 
If you change the colour every year by adding a bit of another colour (swapping a pint with a neighbour is an easy way) then your rubbing down depth is easy to gauge. 80 grit w&d is pretty rough (I use 400) and probably removes a fair amount.
If the surface is still good, don't stress. It is when it starts flaking off that you need to think about stripping.
 
awol said:
If you change the colour every year by adding a bit of another colour (swapping a pint with a neighbour is an easy way) then your rubbing down depth is easy to gauge. 80 grit w&d is pretty rough (I use 400) and probably removes a fair amount.
If the surface is still good, don't stress. It is when it starts flaking off that you need to think about stripping.
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I've done fifteen years without stripping, using Optima mostly. I was going to strip this year but spent my pennies on new sails. The build-up is only getting thick around the waterline, which I might rub down if I can be bothered.
 
We have 40 layers!
I partially stripped one side last year. The boat didn't go in circles last summer, nor did it list to Port, but I did notice more growth where I'd removed the layers.

I questioned why to do this at the time. Gave up with only half it done, and now question why I bothered starting.
 
Attack it when the thickness leads to flaking. If it it eroding, and attacked with wet and dry (mesh wet and dry is more effective at keeping the thickness down), it won't build up very quickly.
 
This year,try painting only the first foot or so down from waterline-just to below the turn of the bilge,plus the top of rudder,if it sticks out into the sunlight.
If you haven,t been getting anything more than slime growth in past,your paint may be good in shaded areas for 2-3yrs. A few days in fresh water does wonders also.
Cheers/ Len
 
The antifoul on my last boat became flaked. Removing it wasn't a job I fancied so over 3 to 4 seasons I only selectively applied new antifoul to bare hull only / where it had flaked. Over the course of time, the multi layered portions seemed to erode away quite nicely leaving a more even applied appearance. Seems that we apply far more than is necessary and that it does its job year after year quite satisfactorily.
 
I scraped the top six inches or so a couple of years ago when it began to flake. A far easier option than wet abrading, using the tool attached to a vacuum cleaner hose. http://www.force4.co.uk/department/...ves-scrapers/vacuum-scraper.html#.VL4Q0SWzWcw Previously I have totally scraped the whole hull with it, rather tedious but much more pleasant than sanding. It is worth grinding the corners off the blade to avoid them digging in to the GRP.
 
vyv_cox said:
Many years ago some famous yachting person said that the time to remove it was when it became possible to use it as a step!
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Quite. I've never removed anifoul, just paint on top each time. I've often looked at people scraping it off each year and wondered why they bothered.
 
We have got to the stage where the antifoul is now flaking off so we will have to scrape it back at the end of the season. As it's the first time we have done it, how long, roughly, should it take to de-antifoul a 33' fin keel Furia by scraping? The various blasting options are limited in Empuriabrava.
 
A frelance guy who does lots of work in our yard did our 27foot boat in two days using a scraper and finishing odd with a random orbital to give a key. We got him to apply coppercoat - he did a very nice job. I think the scraping will vary from boat to boat, our old anti-foul had been on over 10 years and was quite thick but it came off fairly easily.
 
colind3782 said:
We have got to the stage where the antifoul is now flaking off so we will have to scrape it back at the end of the season. As it's the first time we have done it, how long, roughly, should it take to de-antifoul a 33' fin keel Furia by scraping? The various blasting options are limited in Empuriabrava.
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If the intention is to remove most of it down to a reasonable base for recoating I think you would scrape a boat that size in a morning. When I did mine it was to apply epoxy, so every particle needed to be removed. I think that took us two weekends but not working on it full time. I was younger and fitter then though.
 
It will be for epoxy. I'm wondering whether to do it ourselves or get the yard to do it at €40 per hour so you see where I'm coming from!

It will be a pain to do it ourselves though as time is often an issue.
 
picardy said:
This may sound like a silly question but my 34 yacht (2007) has numerous layers of antifoul (6-8) in my 3 years of ownership alone.
Thanks
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Drifting thread slightly... that seems like an awful lot of antifoul in 3 years, I usually make one covering (of two layers) last three years with just a touch up of worn areas and a quick, light wet sand of the rest. Based in a locked marina might help I suppose.
 
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