DOCKWALK ≈ AUGUST 2007 79

TBT is a thing of the past and copper looks to be on the endangered list. Bottom paint manufacturers are struggling to stay ahead of mounting environmental regulations.

By Bransom Bean

score one for the

BARNACLES

When was the last time you heard, “did you see the fabulous bottom on that?!” (referring to a yacht’s bottom, of course). Despite the fact that bottom paint now comes in many more colors than the good old standbys of red lead and

aquamarine blue, there is probably no less sexy superyacht topic than bottom paint – well, okay, maybe black water. while unseen and unappreciated by many, yacht antifouling is getting more time at center stage as environmental regulations bloom faster than the marine organisms they’re meant to protect.

The major manufacturers, including international (interlux), hempel, sea hawk, Jotun, seaJet and Pettit, are trying desperately to balance

environmental concerns and legislation against performance. Their best tool, tBt, has been banned globally and their centuries-old standby,

copper, is coming under increased scrutiny. Relative newcomers, like ePaint, claim to be taking a totally new approach using ordinary light.

and in one of the more interesting nautical ironies, the best solution to the fouling problem – super-smooth coatings that work brilliantly

on tankers and container ships with no poisons at all – isn’t a good solution for superyachts.

americans would point to California as leading this environmental charge but it should be remembered

that Denmark has restrictions on any craft that can’t be hauled out of the water by four men,

sweden doesn’t allow copper antifouling on its Baltic coast and it is the imO that’s

banning tBt as of January 1, 2008. interestingly, the Dutch apparently

banned copper and then relented, noting that it is a naturally

occurring element – but then again, so is arsenic

(number 33 on the periodic

table).

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80 DOCKWALK ≈ AUGUST 2007

WhAt iS hE tALkiNg ABout?strictly speaking, bottom paint includes the primer that coats the bare metal, composite or wood, a tie-coat such as hempel’s neXUs and the antifouling paint on the surface, which is our focus here. as a system, all of this serves several vital purposes, including helping to prevent corrosion in metal hulls and osmosis in composite hulls, as well as slowing the deterioration of wood.

The antifouling bit helps keep the bottom smooth, fast and efficient, thus saving fuel. Things attached to a vessel’s bottom, like barnacles and weed, have mass – hence weight – so discouraging them also makes a vessel lighter. adding insult to injury, once these organisms manage to attach themselves, they are expensive to remove, especially now that you can no longer just dump what comes off down the drain.

incidentally, not all yachts bother with antifouling. Racing yachts, for example, and apparently the King of spain’s 70-plus-knot, 41-meter Fortuna, often are dry-sailed.

antifouling, as the name suggests, minimizes “marine biological fouling.” also known as marine biofouling, it has been defined as the undesirable accumulation – begging the question, is it ever desirable?

– of microorganisms, plants and animals such as worms, mussels, barnacles, as well as algae and slime on artificial surfaces immersed in seawater. You only have to look at a pier’s pilings at low tide to see what would happen underneath one’s otherwise perfect superyacht without antifouling. and it doesn’t take a Ph.D in Fluid mechanics to understand how all those weeds, slime and barnacles would slow down any vessel (speed varies inversely with weed), not to mention being downright superyacht ugly.

two more interesting ironies, this time environmental: First, there is a recognized beneficial trade-off, (probably seen by environmentalists more as a dilemma), between the poisons in antifouling and the reduced fuel consumption that clean bottoms achieve. secondly, as the world focuses on non-indigenous invasive species like zebra mussels entering the Great lakes in ballast water of ships, environmentalists also are forced to acknowledge that if an antifouling biocide keeps a Greek beastie from attaching to the hull in the aegean sea, then it can’t ride across the atlantic to attack unsuspecting american manatees in Fort lauderdale.

A CENtuRiES-oLd StRuggLEBottom line: all materials immersed in seawater soon have things growing on their surface.

The war against marine growth on vessels has been raging for centuries and many of the techniques and materials of the past are still in use today.

The Vikings attached sacrificial wooden sheathing (reminiscent of sacrificial zinc) to the “real” hulls of their longboats. They were simply stripped off when bottoms became weedy, so pillaging operations would not be slowed.

Of course, unprotected wooden hulls are also attacked by creatures that actually eat into the hull such as teredo worms (also known as shipworms or teredo navalis) and gribbles.

teredos – which are not really worms at all but are actually bivalve mollusks, or clams if you prefer – upon finding a particularly appetiz-

ing unprotected hull, quietly bore in and disappear until, so riddled by their unseen appetite, the wood breaks apart, hopefully not during a storm in the southern Ocean.

if, like the author, you’re old enough to remember the origi-nal Star Trek series, gribbles might first conjure up fuzzy images of those cuddly, purring and exponentially procreating tribbles (“The trouble with tribbles” – 1967, episode 44). hardly cuddly, gribbles are actually flea-sized crustaceans with seven sets of legs, four moving mouth parts and a voracious appetite for wood-borne bacteria, according to National Geographic News. “Beam me up, scotty.”

Following the second century practice of the Romans, the (British) Royal navy in the 1600s tried sheathing their ships with lead to deter the worms and gribbles, but replaced it with copper sheets in 1770 when it was noted that virtually all of the lead had fallen off hms Marlborough.

Copper sheets, 48 inches long and 15 to 18 inches wide, were laid over a coating of pitch, tar, hair, yarn and brown paper. not only was the copper physically impenetrable to worms, but it was soon discov-ered that copper actually slowed the growth of weed by produc-

ing a noxious film of oxychloride – the first biocide. Because this film was slightly soluble, it washed away or self polished – the first ablative coating.

Unfortunately, the British admiralty also soon discovered that the copper reacted galvanically with the iron bolts that held ships together, eroding many to

the point of near uselessness – also bad practice for the southern Ocean. That’s the same reason why aluminum superyachts today avoid coatings that contain copper and everybody has sacrificial zincs.

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The Dutch apparently banned copper and then

relented, noting that it is a naturally occurring element

– but then again, so is arsenic.

Captain’s Log: Score One for the Barnacles

82 DOCKWALK ≈ AUGUST 2007

So, juSt NukE ’Emas hulls switched from wood to steel, copper and other

substances even more annoying to aquatic species, particularly tin, found their way into paint,

replacing those copper sheets. marine antifouling coatings were born. it was a bad time to be a barnacle.

Unencumbered by the likes of Green-peace, the ePa or even the imO, the war on fouling escalated in toxicity, ramping up with poisons, includ-ing cuprous oxide, mercury, copper and arsenic. The best of all came in the 1960s – tributyl tin oxide, or tBt.

“who cares, nobody drinks seawater, except fish.” indeed, talking today with coating veterans of that pre-Rainbow

Warrior/Silent Spring era, you can’t help but detect a slight twinge of longing for the good old days of tBt. it’s long lasting, incredibly effec-tive, easy to apply and best of all, cheap. But when fish started dying en masse in harbors full of boats coated with tBt, the handwriting was on the wall.

aaah, for simpler times.

PoLitiCALLy CoRRECt ANtifouLiNgas the goal went from killing the beasties wherever you found ’em to sympathetically making organisms in the sea’s ecosystem happily go away without hurting their feelings, guess what? The price went up. in fact, other than occasional shortages of copper, environmental regulations are now the reason antifouling is so expensive and it’s easy to see why.

Coatings must comply with air emissions standards, VOCs regula-tions and other bureaucratic protections, such as the U.s. Federal insecticide, Fungi-cide and Rodenticide act

(FiFRa) and neshaP regulations – whatever that is – and be registered by organizations such as the ePa and the imO. if you’re interested in more detail, the sleep-inducing www.antifoulingpaint.com has a most helpful list.

“Basically, we’re being asked to be environmentally friendly but at the same time kill everything that touches your hull,” says interna-tional’s advisor in the Balearics, Dennis moshofsky. “as government agencies keep banning, paint manufacturers are just trying to keep up with new regulations.”

doN’t go AWAy mAd, juSt go AWAywith the trend definitely moving away from biocides and even cop-per, what is being done? The most environmentally friendly method sounds almost too simple – and for superyachts, unfortunately, it is.

why not just make the bottom of a vessel so smooth, super smooth in fact, that organisms simply can’t stick – remember what teflon did for eggs in a frying pan? no poisons, no biocides, just silky smooth. (and before you ask, teflon is very expensive, not easy to apply and cannot be over-painted for maintenance unless the previous layer is completely removed, so, no, it won’t work.)

well, they do make vessels super slick. Jotun, hempel, interna-tional, all of the majors have a super-slippery product that works great…on ships. Using silicon and the motion of the vessel, organ-isms are gently whisked off a hull to swirl happily away in the wake. all that’s left is a thin coating of very slippery slime. international says that its new intersleek® 900, in terms of fuel efficiency and reduced emissions, “…could mean savings of over forty-five hundred

tons of fuel, a reduction in carbon dioxide emissions of over fourteen thousand tons and Us $1.2 million over a five-year period,” – for a tanker, that is.

another, albeit slightly less friendly, method takes its cue from the early copper sheets of the Royal navy with the antifouling simply wearing off as the vessel moves though the water and as it does, gradu-ally leaching – surely there is a regulation against a word like leach-ing – more “friendly” biocide. But for superyachts, except perhaps expedition yachts, there’s a problem: motion, or rather the lack of it.

of CouRSE, SuPERyAChtS ARE diffERENtYou could be forgiven for thinking that if superyachts have one thing in common with their commercial cousins, it would be antifouling bottom paint. Particularly as yachts reach cruise-ship size, surely when it comes to bottom paint, what’s good for one ocean-going vessel must be good for another?

well, of course, you’d be wrong.The problem, you see, is that for super-slippery

and most ablative coatings to work well, the vessel has to move through the water,

Talking today with coating veterans of that

pre-Rainbow Warrior/Silent Spring era, you can’t

help but detect a slight twinge of longing for the good old days of TBT.

Captain’s Log: Score One for the Barnacles

Marsha Kay, a 118-foot Trinity, at Bradford Marine

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84 DOCKWALK ≈ AUGUST 2007

at all but a wax polymer. Produced by Dutch manufacturer Qia, it is a super-slippery product and said by stockholm University to be entirely non-toxic to marine organisms. Unfortunately, it requires motion as well.

a Falmouth, massachusetts, Usa company called ePaint has taken an entirely new direction with a patented photo-active approach using visible light, oxygenated water and a catalyst to generate peroxides. ePaint says it’s “non-toxic” and the U.s. navy and Coast Guard seem to agree.

if Billy smith is right and the trend moves towards super-slippery superyacht bottoms, regular cleaning might be in order to make up for motionless weeks alongside.

“in California, bottom cleaning is a culture,” says international’s Colin anderson. But what about in antibes?

Unfortunately, there’s a problem with cleaning super-slippery surfaces. super slippery also means super soft – after all, it is silicone. The solution for this may come from nuclear submarines, which need to clean those soft anechoic hull tiles that absorb sound from enemy sonar. although these tender hi-tech tiles can withstand 30 knots at 800 feet, ironi-cally, they are damaged by a wire brush. so Underwater maintenance Corporation

developed its mini Pamper hull cleaning system. it looks a bit like a 150- by 76-centimeter yellow RV air-conditioning unit with handle-bars. Divers drive the mini Pamper along curves of submarines and supertankers. as it rolls along, two counter-rotating brushes that are not allowed to disturb the delicate surface, whisk organisms away as gently as a feather duster.

as to the big picture of where it’s all going, alex walsh of ePaint perhaps sums it up best, “in the end, the yacht industry has to move away from compounds that persist in the environment.”

That could be pretty far away from where it is now – maybe soft, shiny, slippery silicone and the mini Pamper (maybe even with a slicker name) is just far enough. O

preferably at a speed over eight knots. easy for a container ship or tanker where being motionless for anything over 15 hours is a finan-cial disaster, but almost impossible for a superyacht that spends 10 or so months in port, crosses the atlantic on a semi-submersible ship and is seldom underway overnight.

But that doesn’t mean the paint manufacturers, including those spreading gallons of slippery, shiny antifouling on merchant ships, have given up on unmoving superyachts. although trinity has not begun using it yet, their Billy smith says, “slick paints are definitely the way forward for yachts.”

Jacqui Knott in hempel’s UK offices agrees, “we see it as a huge growth area that we have specifically targeted.” it’s not surprising then that hempel is re-launching its superyacht line.

international says its micron 66 is, “a true sPC (self Polishing Copolymer) superyacht antifouling that delivers the

same outstanding level of antifouling protection as tBt,” – truly antifouling nirvana.

One company that doesn’t have its feet in both the commercial and superyacht antifouling markets is sea hawk. its new “mission Bay” was developed specifically for California. Copper- and tBt-free, it uses the biocide zinc omadine, “which is what they use in head and shoulders shampoo,” says Jason Revie, VP sales and marketing at sea hawk. “and we’re getting a one-year life in harsh conditions like Florida and generally two years elsewhere.”

which then brings us back to more poisons, er, biocides for yachts. while that merchant ship expects a minimum of five years of life from its antifouling, a superyacht is lucky to get two, more biocides or not.

an exception might be Copper-Coat, manufactured by British aquarious marine Coatings, which advertises that it has resistance, “to weed and barnacle growth for a decade or more!” and “fully complies with current (2001) international maritime Organisation (imO) Resolution mePC.102(48).”

hempel claims service inter-vals of up to 60 months with its Globic nCt for all service conditions using nano Capsule technology that can be tuned, “to combat marine fouling more efficiently in a wide variety of conditions.”

so in terms of service life, we may be getting there.

thE WAy foRWARdThere are one or two novel ideas for yacht antifouling. One is safe-Boatskin, which is not really paint

“Basically, we’re being asked to be environmentally friendly

but at the same time kill everything that touches your hull.”

Captain’s Log: Score One for the Barnacles

Hempel’s Globic NCT being applied to Mirabella V

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