Silicon based paint instead of antifouling?

[Graham Pearson]

Reading with interest the wiki entry for the Emma Maersk container ship it states that rather than using a biocide, a special silicon paint is used. Can anyone enlighten me on what it is and if this is common practice for commercial vessels.

 

[Mistroma]

I haven't read the wiki entry. However, this vessel first used silicone based antifoul in 2003. At least 50-60 other large vessels copied this by 2007. People who make International a/f were selling something similar around late 1998 or 1999. I think it was Intersleek or something similar.

N.B. Silicone, not silicon

Yacht antifoul with silicone has been available for a little while now. I assume it is more expensive, less effective or just too new versus other options, otherwise we'd all be using it. Perhaps it has just been very poorly advertised or earlier versions were limited to props. out drives etc.

 

[Neil_Y]

The new port of London pilot boats that we supplied parts for used what felt like a smooth rubbery bottom paint, I think this was the same or similar and it looked good when I was last underneath the boat.

 

[coreng]

Due to probable ban of copper based antifoulings in the next years, several experimentations have been conducted on big ships, especially within US Navy. You will find a commercial/technical notice for recreationnal boats from Hempel here :
http://www.google.fr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&cad=rja&ved=0CEMQFjAC&url=http%3A%2F%2Fwww.boatpaint.co.uk%2Fdatasheets%2FHempel%2FHempel%25202013%2520SilicOne%2520Brochure%2520148x210%2B3%2520UK%2520LR7%2520FINAL%2520VERSION%2520.pdf&ei=J3ihUp33JIWThgeZ9IDIBA&usg=AFQjCNGbzDSbkVdTbpSemsU1s8azka0zaw

 

[Neeves]

Silicone fluoro polymers?

This silicone coating is used on a huge range of commercial vessels. Many cruise ships, naval vessels etc etc are using it. Claimed to last years, 12 has been mentioned, and have significant fuel savings.

I think that is the good news.

It is very delicate, if you ground, lift on slings, there might be issues (neither are normally issues for large commercial vessels). The problem is - its soft (like silicone or Prop Speed). Its also expensive, like Prop Speed. Currently only available in bulk ( not sure what that means - but I'm guessing 200l drums). It seems to be a 3 component system only to be used by trained operators, and the images I have seen. wearing pretty suits, like they do for nuclear accidents. Needs be applied to clean hulls, soda blast or new hulls, and if change your mind getting the silicone coating off is a major worry. I think its sprayed on and you need conduct in a booth (or huge dry dock) to avoid getting on anything else.

There were some trials on a leisure yacht a year, couple of years ago in Holland and America, which appear to have been successful but as its all gone quiet since there must be some issues - maybe the above.

The major players in the field are all working at this end of the market and have, commercial, products on the market. They are aware that we are champing at the bit for something better than 'poison' but we have a little way to go before it becomes commercial, or practical, reality at our level.

But watch that space.

Jonathan

 

[Pasarell]

Silicone polymers have been in the commercial market for many years. International launched an early version of Intersleek in the early 80's. Over the years it has gradually become more practical and the other major marine paint companies have brought their own versions to the market. A couple of half hearted attempts to put it into the leisure market have been made but the only one that has survived so far is Prop Speed.
Silicone polymers work by creating a low energy surface, or low surface tension, that fouling organisms find it difficult to adhere to, but they need to be continually immersed and moving in the water to be effective.
Until recent years they were only suitable for fast moving commercial vessels that were continually active, such as long distance container vessels. 3 or 4 years ago fluoro polymer versions were introduced and these are effective at lower speeds. With silicone polymers International said they were effective at 15 knots service speed with 80% activity. For the fluoro polymer version they say minimum 9 knots at 80% activity. This has brought a much wider market within range and bulkers, crude carriers etc have all tried the products.
More recently some ship owners who were early adopters have started to move back to conventional antifoulings, however, as the practical use of the products is more difficult to manage than the theory suggests. Minor surface damage can lead to major fouling and fuel savings are only realised if the surface is very smooth.
Barnacles can, and do, stick to these products, just not very tightly. When they settle, however, they quickly damage the surface and render the products ineffective. The only way to keep them off in the first place is by maintaining that minimum speed and activity level. Hempel skim over this problem in their brochure attached above.
Various trials have been carried out by all the major paint manufacturers on yachts over the years and all have failed. Even where the minimum speed is attainable almost all yachts, power and sail, fall way short of the activity requirement. This is quite apart from the difficulty of getting the application right.
In case anyone is worried by the comment above about copper being banned in the coming years then you can relax. There is no serious attempt to ban copper in the foreseeable future. Low surface energy polymers may well be the way to go in the future but they are a long way off being ready for the leisure market at this time

 

[coreng]

In case anyone is worried by the comment above about copper being banned in the coming years then you can relax. There is no serious attempt to ban copper in the foreseeable future.

I know it's far from England but, even if it's a small concern and only the beginning :

"Some EU authorities have raised concern over copper compounds used in antifouling paints used in pleasure craft, leading to restrictions and/or bans of copper-based anti-fouling paints in Sweden and the Netherlands. These bans or restrictions have come about through perceived risks to unique environmentally sensitive local environments".

 

[Bodach na mara]

I know it's far from England but, even if it's a small concern and only the beginning :

"Some EU authorities have raised concern over copper compounds used in antifouling paints used in pleasure craft, leading to restrictions and/or bans of copper-based anti-fouling paints in Sweden and the Netherlands. These bans or restrictions have come about through perceived risks to unique environmentally sensitive local environments".

Be interesting to see if the tree-huggers, if they ban copper compounds in AF paints, will exempt marine installations such as tidal generators and tide mills from the rule.

I always thought it was daft that, when TBT was banned, it was only banned for small vessels. A large comercial bulk carrier with an underwater area greater than the total of all the yachts in the Clyde could continue to be protected by TBT. (TBT was also bio-degradable, which copper is not.)

 

[Pasarell]

I know it's far from England but, even if it's a small concern and only the beginning :

"Some EU authorities have raised concern over copper compounds used in antifouling paints used in pleasure craft, leading to restrictions and/or bans of copper-based anti-fouling paints in Sweden and the Netherlands. These bans or restrictions have come about through perceived risks to unique environmentally sensitive local environments".

Can't remember the dates but the Netherlands introduced a ban on copper antifouling back in the 90's I think, then removed it a year or so later. Sweden does have a ban on the east coast but no plans to extend it or for other countries to take it up.
Extensive leaching tests by many organisations have failed to show any significant effect from copper.

TBT was a whole different situation though. Significant accumulations of TBT in harbour and estuarial waters still a problem in many areas. Pretty much all the problem came from small boats as they needed fast leaching products to work. Large commercial vessels had far slower leaching products so that very little got into sensitive areas. In Southampton, for instance, there are still very high levels of TBT in the mud in Ocean Village Marina but virtually nothing at the container port.

 

[Daydream believer]

I know it's far from England but, even if it's a small concern and only the beginning :

"Some EU authorities have raised concern over copper compounds used in antifouling paints used in pleasure craft, leading to restrictions and/or bans of copper-based anti-fouling paints in Sweden and the Netherlands. These bans or restrictions have come about through perceived risks to unique environmentally sensitive local environments".

So how does an owner with Coppercoat antifoulling on the hull when visiting the country get on.
Are they allowed passage or not?

 

[bignick]

When you look at the service pattern of a container ship and it's average speed, you'll find that the requirements for its antifouling are substantially different than those for a pleasure craft which spends most of its life static. Silicone based paints give a low friction surface that fouling washes off, which work for a vessel doing 20+ kts most of the time. I think it highly unlikely they would work as well on a yacht.

 

[boatmike]

When you look at the service pattern of a container ship and it's average speed, you'll find that the requirements for its antifouling are substantially different than those for a pleasure craft which spends most of its life static. Silicone based paints give a low friction surface that fouling washes off, which work for a vessel doing 20+ kts most of the time. I think it highly unlikely they would work as well on a yacht.

You have it there in a nutshell BN. It does not lend itself to use on any vessel that does less than about 10-15 knots and does not like sitting on static moorings for much of it's life. Add to that the fact that it is soft and easily damaged by grounding, slings etc and it's not for us. It's also pretty impossible to remove once applied and nothing else will stick to it.

 

[vyv_cox]

I know it's far from England but, even if it's a small concern and only the beginning :

"Some EU authorities have raised concern over copper compounds used in antifouling paints used in pleasure craft, leading to restrictions and/or bans of copper-based anti-fouling paints in Sweden and the Netherlands. These bans or restrictions have come about through perceived risks to unique environmentally sensitive local environments".

In about 1999 - 2000 the Netherlands government banned the application of copper based antifoulings due to its perceived environmental effects after an incident of fish deaths. It was subsequently found that the deaths were actually due to release of some toxic chemicals. I believe that the ban on copper was later rescinded but I left Holland shortly afterwards so cannot advise the latest situation.

More recent information here http://www.copperantifouling.com/copper/ suggests that a ban remains in what are seen to be particularly sensitive areas.