Anti-Fouling Conundrum

[Irish Rover]

I lift my GRP hulled catamaran every year and get it anti-fouled by the painting contractor in my marina. He says he's applying International but I'm 100% sure he's using the cheapest local paint he can find. I use my boat 4/5 days per week all year around. After around 9 months the bottom gets quite dirty and definitely starts to affect speed. A friend has a Grand Banks Classic wooden hulled boat in the same marina. He has been unable to travel here since early last year and I'm now helping him to sell it. There was a prospective purchaser yesterday and the marina have an arrangement whereby they give you a free lift an an hour in the slings when a boat is for sale. When we lifted it the bottom was as clean as a whistle even though it's more than 2 years since it was lifted and painted and has only left the marina twice in that time for a total of maybe 4 hours motoring. I called the painter to come look and asked him how come this was clean after 2 years and mine is fouled in less than 12 months. He had no explanation and said apart from the colour [red as opposed to black on mine] he used exactly the same paint. I'm stumped. Can anyone offer a logical explanation? Is it because it's a wooden hull?

 

[Adios]

Different place in the marina?

 

[Neeves]

You don't say it was the same painter not the same paint. You say your painter uses International - as far as I am aware International produce a number of products, some better than others and some cost more than others (because they are better). If your friend uses the same painter does he check what paint is used - I would, but then I'm a parsimonious Scot (and would do the work myself). But if I'm being charged for the paint I would expect the painter to be quite relaxed if I were to check for what I was being charged.

Antifouling, approximately, performs to a crude concept. Apply more and better and it performs longer and better. I can vary our AF performance using the same product by applying more or less paint.

Colouer is totally irrelevant (except for white).

If you pay your bills without questioning ........??

Don't blame the painter - he has a family to support and a pension to build.

Take care, stay safe

Jonathan

 

[Irish Rover]

Different place in the marina?

Same corner about 20M apart both alongside rather than pontoon.

 

[ip485]

Seems to me so much varies including the paint used, the number of coats and, importantly, how much the boat is used.

If you have doubt about the antifoul used supply your own next time, no reason not to. Undoubtedly antifouls do vary in quality and longevity, normally related to price as with most things.

As to contractors (and it seems to me you arent actually saying you doubt the contractor) either you trust them to do a good job, or you keep a particular eye on what they are doing to build that trust.

 

[Irish Rover]

You don't say it was the same painter not the same paint. You say your painter uses International - as far as I am aware International produce a number of products, some better than others and some cost more than others (because they are better). If your friend uses the same painter does he check what paint is used - I would, but then I'm a parsimonious Scot (and would do the work myself). But if I'm being charged for the paint I would expect the painter to be quite relaxed if I were to check for what I was being charged.

Antifouling, approximately, performs to a crude concept. Apply more and better and it performs longer and better. I can vary our AF performance using the same product by applying more or less paint.

Colouer is totally irrelevant (except for white).

If you pay your bills without questioning ........??

Don't blame the painter - he has a family to support and a pension to build.

Take care, stay safe

Jonathan

Just one painting contractor in the marina but 12/14 painters working for him. I deal with the owner - he's a rogue and makes little effort to hide it. I said he "claims" to use International but I don't believe him. my friend didn't request or pay for any "special" paint and the painter says the two boats were painted with the same paint. When I started getting work done here initially many years ago I used to buy good quality paint myself and give it to the painter to do the work. However unless I was there all the time I couldn't be sure what paint was being applied and suspected he might be using his own chicken shit paint anyway. If I had he time or inclination to be in the yard all the time to keep an eye on them I might as well paint the thing myself. To be fair the price I pay is probably cheap anyway so I'm just curious how the GB stayed clean for so long.

 

[Irish Rover]

Seems to me so much varies including the paint used, the number of coats and, importantly, how much the boat is used.

If you have doubt about the antifoul used supply your own next time, no reason not to. Undoubtedly antifouls do vary in quality and longevity, normally related to price as with most things.

As to contractors (and it seems to me you arent actually saying you doubt the contractor) either you trust them to do a good job, or you keep a particular eye on what they are doing to build that trust.

Our posts crossed but if you read my previous post I think I'd answered the points you made.

 

[ip485]

Great minds! Yes I am afraid easy to substitute cheap paint which could be part of the explanation, but as I said there could be other reasons as well.

I guess you have probably answered your own question though. It is one of those the answer will possibly never been known. If in doubt swap to a more reliable contractor and use a known product. Unfortunately even if it performs better I am not sure it proves cheap paint was used, as even between seasons antifouls seem to sometimes perform differently - again I suspect down to water temps, and especially how much the boat is used through the season.

Good luck.

(PS and you are right there comes a point if you have to oversee to a significant extent you may as well do it yourself, which rather defeats the point).

 

[TernVI]

The red antifoul is probably some lethal stuff intended only for the navy.
Or there may be lots of strong AF previously applied.
The OP may use his boat too much. While moving through the water helps keep the boat clean, it also accelerates the active stuff leaching out of the antifoul. I used to have a mooring in a lot of current and antifoul never lasted very long.

 

[FairweatherDave]

The OP may use his boat too much. While moving through the water helps keep the boat clean, it also accelerates the active stuff leaching out of the antifoul. I used to have a mooring in a lot of current and antifoul never lasted very long.

That's an interesting thought.....
(says someone who moors in maybe quite a lot of current on a deep water swinger).

 

[Irish Rover]

The red antifoul is probably some lethal stuff intended only for the navy.
Or there may be lots of strong AF previously applied.
The OP may use his boat too much. While moving through the water helps keep the boat clean, it also accelerates the active stuff leaching out of the antifoul. I used to have a mooring in a lot of current and antifoul never lasted very long.

That's a good point regarding use. My wife keeps telling me I spend too much time out on the boat - who'd have thought she knows so much about antifoul.

 

[penfold]

Different colours may leach differently, although unless the motorboat got many extra coats after 2 years nearly dormant in a marina it should be growing a forest.

 

[Neeves]

If colour, apart from white, made any difference we would know and we would all, without exception, use that colour.

However a red AF would come from a different tin to another colour and possibly a different supplier, despite what the contractor might say - would he actually remember - unless he only uses one quality.

As Penfold says - any vessel sitting stationary in warm water, that based on other vessels in the same location has a high fouling ability, should have been badly fouled - unless the AF used was particularly toxic (and might be desirable). I wonder if TBT paint is easily available in the location. Though why one vessel might be 'lucky', and coated with a TBT based product and not another is another question.

It is not that long ago, less than 10 years ago that an America AF manufacturer was found to be adding TBT to its products (I recall the owners went to prison).

Sea Hawk Paints Maker Indicted Over TBT Use

Jonathan

 

[tonijon]

Same corner about 20M apart both alongside rather than pontoon.

It can make heck of a difference. The club I belong to has swinging drying moorings. One chap I know has a inner mooring gets badly fouled despite using very expensive Antifoul (he got me to use 2 pack despite my igorence in not knowing it existed. Our mutual friend moors on the outer moorings doesn't get too much of a problem!

 

[Irish Rover]

If colour, apart from white, made any difference we would know and we would all, without exception, use that colour.

However a red AF would come from a different tin to another colour and possibly a different supplier, despite what the contractor might say - would he actually remember - unless he only uses one quality.

As Penfold says - any vessel sitting stationary in warm water, that based on other vessels in the same location has a high fouling ability, should have been badly fouled - unless the AF used was particularly toxic (and might be desirable). I wonder if TBT paint is easily available in the location. Though why one vessel might be 'lucky', and coated with a TBT based product and not another is another question.

It is not that long ago, less than 10 years ago that an America AF manufacturer was found to be adding TBT to its products (I recall the owners went to prison).

Sea Hawk Paints Maker Indicted Over TBT Use

Jonathan

So are you a white is better or worse advocate?

 

[pvb]

So are you a white is better or worse advocate?

Regardless of Neeves' opinion, you need to look at the specs of the antifouling. Micron 350, for example, has an average SG of 2.2 for all colours except white. For white, it's only 1.9, and that means it has less copper oxide in it. Specific gravity is always a good guide to the likely effectiveness of antifouling. I use black Micron.

 

[Mark-1]

Specific gravity is always a good guide to the likely effectiveness of antifouling.

Useful tip, thanks.

 

[pvb]

Useful tip, thanks.

You're welcome! The other useful tip is always to apply the full amount of antifoul recommended by the paint manufacturers. I see boats being antifouled in the marina by boatyard guys, who seem to make a tiny tin last forever by rollering it out incredibly thinly. It won't last. But they'll get paid again next year for doing it all over again. I give my boat several good coats, applied by brush, and it lasts a full 2 years in the water.,

 

[Mark-1]

You're welcome! The other useful tip is always to apply the full amount of antifoul recommended by the paint manufacturers. I see boats being antifouled in the marina by boatyard guys, who seem to make a tiny tin last forever by rollering it out incredibly thinly. It won't last. But they'll get paid again next year for doing it all over again. I give my boat several good coats, applied by brush, and it lasts a full 2 years in the water.,

Yeah, that I already do. It goes on thick and I never store an open can - that goes too. Much like anchor cable, not much use on the locker.

 

[Neeves]

Regardless of Neeves' opinion, you need to look at the specs of the antifouling. Micron 350, for example, has an average SG of 2.2 for all colours except white. For white, it's only 1.9, and that means it has less copper oxide in it. Specific gravity is always a good guide to the likely effectiveness of antifouling. I use black Micron.

Sorry - this answers the question, I thought it was obvious.

Jonathan