racing antifoul vs Polishing antifoul

S

simonwood

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Hi,


Performance wise, do your boats sail faster with racing antifoul?
I am in to minds to strip my bottom so to speak to put on racing antifoul on.
do you have to strip of prevous Polishing antifoul if i want to put on racing antifoul?

si



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The idea with the hard antifouling for racing, is that you can burnish or scrub to a very smooth surface - penalty is that rather that the toxins eroding away with the carrier, the carrier remains, so each year you have to sand all the carrier paint away before repainting.

I'm in fairly warm sub tropical water, (it's mid winter, and water temp is still 19C) so high growth, but I use an ablative, and with 2 lightish scrubs (with a scotchbrite pad) get 12 months out of the paint. Hard racing would give me next to nothing, and double the effort on the slip (the worst part of owning a boat) to my way of thinking.

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Rick
Interesting to note your problems with high water temps re antifouling.
As I understand the UK is now experiencing higher water temps, & I have noticed a lot of the yachts especially in Marinas seem to be getting more fouled this year, even my Yacht in the Exe, which has a very fast tide, is worse.

You say you use an Ablative paint, which one? as I will be looking at a new system this winter to cut down (hopefully) the fouling for 2005.

poter.


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This is about having the the hull surface as smooth as possible. Without going into boundary layer fluid mechanics, the more rough the surface the greater the resistance of the water - hence less speed or more power to achieve same speed if you are a MB or Ship. This roughness can be clean rough paint surface, weed, slime barnacles etc. Keen racers will not have any antifoul, very shiny smooth hull waxed and polished before each race and no paint. This is mucho agro and is generally not for we humble cruisers hence self polishing paints etc . If you are mooring in high tidal streams or have high speeds then a harder paint is deemed better to last longer as as the self polishers rapidly erode in high water velocities but the hard base does build up and needs removing after 4/5 years. I aim to put just enough selfpolishing on to get back to the Gelshield coating each year, but this is trial and error for each location.

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When I had an X99 I used first eroding and then hard antifouling. If there was any speed difference, I didn't notice it. What I did notice though was that it needed stripping off after 3 years back to gelcoat because it was becoming lumpy. This was an expensive mucky time consuming job that took a whole month of weekends. Never again.

If you are interested in the last bit of performance, new sails may be a better investment (or a trimaran ;-)

<hr width=100% size=1>One day, I want to be a real sailor. In the mean time I'll just keep tri-ing.
 
Good advice from this board again, thanks!
I'll think i'll leave it, i striped my last boat to epoxy, your right never again, i was hoping you would say well i saw 0.5 knot extra, but if not, i can't be bothered!
thanks for your help

si

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I did this last winter, as I had several years worth of eroding antifouling (Micron) build up resulting in a horrible lumpy rough finish which certainly wasn't quick. However it was a real painful job getting it all off, which I don't want to repeat in a hurry, so to try to avoid the build-up problem I've put on International VC17M - the thin-film stuff which they say is a tenth of the thickness of the normal antifouling. It certainly has given a great finish even without polishing - feels a bit like the inside of a non-stick frying pan!

The only downside is that there's only one colour - "Graphite".

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I generally use Altech AF3000 (an Australasian Company who used to make US paints under licence down under), however last year I used Jotun Seaguardian (three boats got a bulk deal_ and I was pleased with the results. Used the last of the AF3000 on one side of the keel, and at haul out this year, the Jotun out lasted the AF3000 on the keel. Just checked and looks like Seaguardian may be an Asia Pacific product only - or a rename of something you get in Europe.

This year I've changed again to Wattyl Eco S - but only changed as I won the paint so saved myslef a couple of hundred dollars - the Wattyl seems softer than the Jotun / AF3000, but it is lasting well. Had it's first scrub last saturday before a race, and that's over 6 months since painting. BTW my boat is in the water all year round, except for a few days for antifouling, and is generally used 2 or 3 times a week, so my bottom paint probably needs to last a lot longer/ work harder than a UK boat.

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Simon,

I'd say unless you've got a hotshot race boat, you'll get as much performance gain using hard racing as you would by leaving one crew member behind, putting the crew on a diet, or putting the boat on a diet ... :-)

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Re: Copper epoxy = racing smooth?

Could one of these copper-epoxy paints be polished up to a racing finish?

I guess the answer is no but I am asking because in November I should have a yacht with a just a gel coat bottom and an agent asking what I want done.


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Marginally

providing you regularly wash/run down and you start with an utterly smooth bottom.
The speed increase is probably in the order of 1-2%, and is due more to the constant smoothing than the paint fromulation.

I hope this answers your question?

PS If you dry-berth use hard sntifouling, the self-eroding soon flakes off when dried out.

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For what it's worth, I think swimming before a race makes a very useful performance difference - particularly in lighter weather and particularly upwind. You will be more competitive.

But the moment you wipe ablative, great clouds of antifoul swirl off into the water and it's fairly useless.

Hard racing antifoul is however nowhere near as effective as ablative, so if you don't wipe/scrub it, coral appears very quickly. You have to be prepared to swim regularly or you'll be very disappointed.

I can get nearly two years out of antifoul, but I swim before every race and I race fortnightly, so I sometimes wonder whether my $4 scourer is actually doing a better job than the $200 can of paint.

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Immersion

in UK waters tends to be more uncommon than down under.

This is partly due to the water temperature here but probably has more to do with shame about physique amongst Brits.

The outdoor life is far less popular in UK than in Oz, especially when you compare Westward Ho or Porth Nwgheill with Bondi (or Gold Coast).

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Re: Immersion

The only good thing about Westward Ho! compared to Bondi is the temperature of the air & the water. I really don't understand how anyone can avoid melting in Oz.

Regards

Richard.


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