If you're not eco aware, you're nowhere

The story is about a new, environmentally friendly coating that protects metals against corrosion in seawater by encapsulating spores from a bacterium into a sol-gel coating, which then protects an aluminium alloy from microbial corrosion.

It turns out that microbially-influenced corrosion (MIC) of metals at sea is a big safety and financial problem that costs the UK around 3-4% of GDP. And existing anti-corrosion treatments are costly, ineffective and often include biocides and inhibitors that are toxic to aquatic life.

The same used to be said of antifoulings, which is why the launch at this year’s London International Boat Show (LIBS) of an antifouling that makes use of nanotechnology was so interesting.

I-CanNano is based in India and makes a range of nanotechnology paints and coatings. The company says nanotechnology is the only process that can be described as truly sustainable.

It uses engineered natural ingredients to provide products that are not material resource hungry, don’t contain harsh chemicals but deliver performance that typically outlives traditional products by a factor of 300%.

This, of course, means less painting, less ingredients, cleaner surfaces, better air quality, UV and bacterial resistance, dirt and water repellency.

They say it’s a longer lasting, highly sustainable solution that actually helps the environment.

As an example, they point to the company’s Nano Pollutant Absorbent paint. Ideal for chimneys, tunnels, exhaust pipes or even painted on roadside hoardings. This paint has a honeycomb structure that they say acts like millions of little bins by absorbing C02 emissions out of the air.

What's in the paint?
The simple answer is paint, except it has no lead, chrome, benzene, formaldehyde or other chemicals. It’s simply paint or a coating, whose molecular structure has been engineered using bonded, non-toxic, non-allergic, alloy based nano-particles as a practical way to exploit their germ, weathering, energy retention, protective barrier, absorption and combative characteristics.

In short, nano paints derive their performance though the minute scale manipulation of molecules rather than large scale chemical infusion.

Manipulation
Nature is the biggest manipulator of molecules in the world. Animal and plant life adapts to its environment to resist attack at the molecular level, whether it be abrasion, bacteria, or pollutant. That's what I-CanNano says it’s done with paints and coatings.

‘We studied nature for 10 years and copied its tactics at the nano level to make breakthrough products that can cope with everything that man and nature throws at it (dirt, bacteria, carbon dioxide, acid and alkaline rain, etc).’ says I-CanNano.

Not new
As I pointed out in our Paints & Coatings feature a couple of months back, nanotechnology is not new. But what is new is that scientists are discovering intriguing new applications for it.

A new antibacterial nanotechnology based paint containing nanoparticles of titanium dioxide was found last year to kill bacteria when it absorbs ultraviolet rays from the sun.

Scientists have also discovered the new paint is not only antibacterial, but it also helps in destroying dirt. These nanoparticles, apparently, ultimately produce active molecules that help in cleaning surfaces.

I-CanNano itself produces a Thermally Insulating Paint. Another paint company produces Nansulate. It uses nanotechnology to insulate whatever it is painted on.

This company is also working on an agent that will counter dirt and paint damage, so we'll have car windscreens that no longer steam up, or paint that no longer gets dirty or can be scratched.

Nanotechnology, it seems, knows no boundaries and we’ll see a great deal more of it in the future.
I-CanNano products are distributed in the UK by Paint Protection Systems - paintprotectionsystems.com

But there are other ways of keeping growth off the bottom of a boat and three similar systems were launched last year. The first was the Ultra System, which was launched at the Southampton Boat Show by David Sothcott, who runs Ultrasonic Antifouling Ltd.

Mr Sothcott’s Ultra System was available in two models; the Ultra 10 for boats up to 10m and the Ultra 20 for boats up to 20m. The basic difference was the 10m model came with one transducer and the 20 came with two transducers.

The transducers are bonded to the inside of the hull – no holes are made in the hull. Careful placement of the transducers is the key to success, said Mr Sothcott.

The transducers were connected to a control box that sent a variety of pulsed ultrasonic signals to them. In turn, the transducers emits a series of low power, high frequency sound waves that are virtually inaudible to the human ear.

The sound waves create a wall of moving water molecules over the whole surface of the submerged hull, creating what Mr Sothcott said is a ‘micro-environment that kills algae and prevents barnacle growth.’

He said the ‘science’ in the system is the creation of the correct frequencies and the harmonics that are set up as a result.

While this technology is new to the marine market, it is, says Mr Sothcott, ‘an established method of preventing fouling in ponds, lakes, reservoirs and even greenhouses.

The company recently launched an upgraded system that adds ‘intelligent’ switch mode technology to the Ultra system with the new Ultra 10 dual and Ultra 20 dual.

This smart recognition technology recognises the power supply available and automatically switches to the best option, removing the possibility of the unit being accidentally switched off.

The benefit is that the Ultra system works constantly to protect your hull from fouling, so if you have a pontoon berth and you remove your shore power, the system will automatically switch to your boat’s battery supply. It will switch back when you return to your berth.

‘The Ultra system is neat and unobtrusive and can be self-installed,’ says Mr Sothcott. ‘Other systems have to be installed by a specifically trained engineer at extra cost, or risk negating the boat’s warranty.’
Ultrasonic Antifouling Ltd – ultrasonic-antifouling.com

Versadock International's 2B Sure electrical antifouling system was launched at METS last year. It's described as an anode antifouling system from Bright Spark, which differs from the other two ultrasonic systems mentioned in this article by the anodes not requiring installation – or contact with - the hull.

The system works on any hull material and features two electrodes that are suspended just below the waterline, one at the bow and one at the stern.

Both are connected to a control box, which sends an electrical current to the anodes and releases a limited cloud of copper ions into the water. These do not harm sea life or the environment.

The movement of the ions along the electrical field within the water prevents fouling – the growth of barnacles, mussels and other forms of unwanted organic matter.

As with the other ultrasonic systems, the 2B Sure protects both the hull and stern gear and leads to improved performance and reduced fuel costs.

The system is simple to use and operates on either 12/24VDC or 110/240VAC. Minimal power is used and the field density and strength of the ions can be adjusted from the control box.

A single 2B Sure antifouling system is sufficient for boats of up to 20m long.

And, as the transducers are suspended in the water, it's the water surrounding the boat that is - in effect - antifouled. So the transponders could be left on the marina pontoon and fired up when the boat's in the berth.

Or, the marina could install a 2B Sure system to cover specific berths. Or even the entire marina. Now that could be a value-added system for any marina.

'The results are amazing,' said Versadock's Chris Wilson. 'The system has been tested by The Royal Netherlands Institute for Sea Research (NIOZ) and extensive tests have been undertaken on boats and North Sea navigation buoys – with great success.

On boats and ships the continually clean hull gives consistent unimpaired performance, reduced fuel charges and considerable savings in the costs of lift out, boat scrub, bottom paint and burnishing, he added.
Versadock International – versadock.com

Claiming to be the world’s first comprehensive ultrasonic marine antifouling system, Blue & Green Marine’s Hull Protection System was launched at METS last year and promptly got a Special Mention in the Marine Electronics category and won the overall DAME Award for Most Eco Friendly Product.

The company says its Hull Protection System will keep yacht and motorboat hulls totally clear of algae, slime, weeds, worms, molluscs and shellfish without the use of traditional antifouling paints which contain poisonous chemicals that leave a toxic legacy in the environment.

The key to the efficiency of the system lies in the destructive power that ultrasound has at a microscopic level. The system creates a finely-tuned pulse of ultra-high frequency sound waves in the water touching the hull. These waves cause microscopic cavitation within the cell walls of the single-celled organisms that form a layer or ‘bio-film’ around all objects immersed in water.

This fierce cavitation is harmless to gelcoat but disrupts the cells’ structure – making the hull uninhabitable to algae and bacteria. This removes the first link in the food chain, preventing larger more complex organisms from colonising any part of the hull, keel, rudder, prop-shaft, propeller, thrusters, water intakes or through-hull fixtures.

The ultrasonic transducer, which is built to exceed MoD specifications, is bonded to the inside of the hull and connected to a bulkhead control panel. The system switches automatically between battery and shore power and has a tiny current draw of 0.06A. The unit is silent and does not interfere with any onboard electronics.

The ultrasonic pulses also have no effect on the boat’s anodes, are harmless to fish and inaudible to marine mammals.

The system - which requires specialist installation by one of the company's fitters - is undergoing full trials at the National Oceanographic Centre, University of Southampton with the help of the facility’s various survey vessels. Blue & Green Marine has also received many enquiries from some of the world’s biggest boatbuilders who are considering the system as OEM equipment.

The system can be used on aluminium, steel, GRP and ferro-cement hulls and is, they say, likely to find favour with larger pleasure craft, megayachts, commercial and military applications; however, it is also ideal for the owners of any smaller leisure craft looking for a serious alternative to the usual antifouling regimes

'Recognition from the DAME Awards jury is testament to the performance of our Hull Protection System,' said Mike Arnold, MD of Blue & Green Marine. 'Antifouling is a huge area of concern on both commercial and ecological grounds and we are the first company in the world to develop and patent a product specifically for the marine sector.'
Blue & Green Marine – blueandgreenmarine.com

But eco-awareness isn't just about antifouling and many will be surprised to find those quiet chunks of metal bolted to rudders, outboard motors and propeller shafts also play a part in depositing nasty things - like poisons - into the water.

Sacrificial anodes are usually made from zinc, aluminium alloy or magnesium. Of the three metals used, by far the most 'eco-aware' is aluminium alloy.

Performance Metals, which makes only aluminium alloy anodes in its USA factory, says its aluminium alloy made to the US Mil standard A24779 is 95% aluminium alloy, 5% zinc with a trace of indium.

When compared to the commonly used zinc, which is a poison, aluminium alloy anodes are 95% less toxic.

And they can be used in fresh, brackish and salt water. Zinc is good in salt water; magnesium is good in fresh water and aluminium alloy is good in all three.

Mercruiser and others only fit aluminium alloy anodes - regardless of the water in which the units will be used.

On the technical side, Perfomance Metals says aluminium alloy develops 1.1V negative. Zinc only develops 1V negative. The company then points out the American Boat and Yacht Council (ABYC) publishes a one inch thick Corrosion Manual that says at least 250mV potential difference is necessary for effective corrosion protection between the voltage of the anode and the voltage developed by the metal being protected.

The aluminium alloy of sterndrives/outboards develops 0.8 - 0.9V, which means the required 200mV potential difference is not developed by using zinc but is by using aluminium alloy.

The company also uses a patented red spot indicator which shows when 50% of the anode is wasted indicating it is time to change the anode.

Performance Metals' anodes are available from Aquafax Ltd

But going back to antifouling for our final shot, while putting the stuff on means usually leaching toxic substances into the water, taking it off again is equally harming to the environment.

Until a company called Ibix came up with what it calls an eco friendly blast cleaning system for the removal of antifouling coatings.

The company has been selling throughout Europe, but is now established in the UK to supply the equipment and provide technical support.

The blasting system works on low pressure and uses garnet, which is a natural chemically inert mineral abrasive containing no toxic metals, silica or ferrite – it's ecological and environmentally friendly and falls well within the legal limits for silica, toxic and carcinogenic.

The system can be used wet (the water acts as a dust suppressant) or dry but the mixing of water and garnet occurs at the nozzle and not in the hopper. When used wet it only uses low volumes of water so any residue can easily be contained to prevent slurry from running into the water.

Ibix says the system is simple to use and simple to control and will not damage gelcoat. The company says the system and the blast medium are low cost and can be used time after time.
Ibix UK - ibixukltd.co.uk