new product for bottom anti-fouling

[bobola]

web site here; http://chemistry.nrl.navy.mil/6110/6...exsilicone.php

The fouling of marine vessels is a significant Navy problem. Marine fouling can increase fuel consumption by as much as 20%. Historically, marine antifouling paints have used compounds toxic to marine organisms as a means of combating fouling. The environmental impact of these toxic coatings has come under increased scrutiny. There is increasing concern about the toxic exposure to shipyard workers and the disposal of hazardous waste from antifouling paints removed during ship maintenance and repainting. Also, industrial and municipal facilities have incurred costs due to the clogging of water intake systems. Traditional methods for controlling biofouling of water intakes depend on the use of targeted chlorination.

NRL patented an advanced foul-release coating system called the duplex silicone coating system. This coating system employs a tough, cross-linked thermoplastic elastomeric layer to bond the foul-release silicone topcoat to the anticorrosive layer. The mechanical properties are imparted by this layer, while the topcoat provides the foul-release characteristics. Because they employ a physical rather than chemical means to reduce fouling, these coatings have been ruled exempt from reporting under the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA; Public Law 95-396). They do not contain the toxic metals of antifouling paints and comply with anticipated restrictions regarding VOCs well into the next century. Foul-release silicone duplex coatings are compliant with current lead restrictions and contain no carcinogenic compounds.

[delmarrey]

What ever happened to Teflon paint. Did it not work???????????

[hellosailor]

Delmarrey-
According to the nice folks I spoke to at DuPont, who own the Teflon trademark, teflon paint "can't" work because it isn't really teflon. They didn't endorse it.
"Teflon paint" was some type of teflon particle or dust in another carrier, and the problem there is course is how do you bind the teflon on/it while not presenting enough carrier around and between the teflon bits, for the critters to grow on the carrier?

DuPont would prefer that you "properly" teflon coat things, which means spraying or dipping on the resin and then baking it at high temperature to set it and bond it.

You could do that to a metal hull, or to a prop or shaft, but AFAIK no one has published anything or tried marketing it that way. Of course baking fiberglass hulls at high temperatures is very good for boat brokers but a little rough on the soon-to-be-ex owners and insurers.<G>

"'Scuse me Chief, would your firemen like marshmallows and cocoa while you're here?" <G>

[fstbttms]

Regarding "foul release" coatings; there are quite a few of them on the market now. Do a Google search and you'll find a bunch. The upside to all of them is they are non-toxic. The downside to most of them is that they are expensive, difficult to apply and require much more frequent cleaning than do traditional, copper-based anti fouling paints. Just my $.02.

[hellosailor]

IIRC there's a "global" ban coming up on copper-based bottom paints, basically extending the same ban on toxins that exists for TBT.

So we can expect all sorts of new products...or crusty bottoms...in the decade ahead.

[fstbttms]

Well, there is no doubt that copper-based paints are on their way out. But I believe the "global ban" you refer to is aimed at tin-based paints, which are still legal in some places and on very large ships in most places. Here in California (San Diego Bay especially), the heat is really on to reduce cuprous oxide in the water column. But the timeline to do what the EPA wants (which essentially would entail the elimination of copper-based paints) is quite long- 17 years. And that's just in the Shelter Island Yacht Basin in San Diego. The rest of the state is only just coming under the kind of scrutiny that San Diego has been under for years.

[AudreyK]

and comply with anticipated restrictions regarding VOCs well into the next century

Must be fantastic stuff if they think they'll be selling it for the next 100yrs or more!

Audrey

[Alan Wheeler]

So who is saying copper is to be phased out????
What problem is copper causing????

[fstbttms]

Originally Posted by Alan Wheeler

So who is saying copper is to be phased out????
What problem is copper causing????

Here in California, boats using anti fouling paints with cuprous oxide as the biocide have been identified as a "point source" of pollution. The copper that passively leaches from these paints and that is removed during in-water hull cleaning activities ends up in the water column and bottom sediment, raising the copper content of both to levels that have been measured to be above USEPA water quality standards. Years ago, the USEPA mandated that California reduce these copper levels and the ball is beginning to roll, starting in San Diego's Shelter Island Yacht Basin. The regulatory agencies in California responsible for making sure this happens have laid out a 17-year plan to reduce copper in the water there by over 70% (I forget the exact amount.) Reaching this goal ultimately means cuprous oxide-based paints will have to be eliminated.

Of course, this currently pertains to SIYB only and the dust hasn't settled on the issue yet either. But it seems clear that, in the US at least, the trend is towards the elimination of copper-based paints.

[GordMay]

Most Tributyltin-Free antifouling paints use heavy metal compounds , such as “cuprous oxide” (Cu2O), or “cuprous thyocyanate” (CuSCN), and sometimes “booster biocides”, as the active ingredients in preventing fouling attachment. Unfortunately, these antifouling coatings, designed to slough or ablade away, leach into the aquatic environment, where they have been shown to be toxic towards non-target organisms.

There is evidence to show that certain species of fish, and other marine organisms are sensitive to quite low levels of copper, even though other species are relatively tolerant of much higher levels. Marine invertebrates are thought to be slightly more sensitive to copper than fish.

San Diego Antifouling Paint Report: http://www.dbw.ca.gov/antifouling.asp
http://seagrant.ucdavis.edu/ReportAntifouling04.pdf

[Canibul]

A lot of boats in a small fresh water lake would seem to be something to worry about. A relative "handful" of boats in a huge ocean thats already mining its own copper?

[hellosailor]

Wheels-
"For now, the copper paint ban must go to California's Office of Administrative Law and the federal Environmental Protection Agency for approval. If approved by both agencies, a separate plan for enforcement would need to go through public workshops, hearings, and regional board deliberations before becoming final. For more information and updates go to RBOC.org." From a Nov.2005 BOAT-US article.

While I was looking at the international TBT bans some months ago, I found a number of similar comments from multiple sources, and discussions proposing that copper-based bottom paints be treated the same way that TBT is, as soon as practical. There's no certainly that this will happen--but there appears to be a lot of support for it, I wouldn't bet on whether copper bottom paints will be mainstream or legal in ten more years.

[fstbttms]

Originally Posted by Canibul

A lot of boats in a small fresh water lake would seem to be something to worry about. A relative "handful" of boats in a huge ocean thats already mining its own copper?

The concern isn't about "a huge ocean." Coastal waters and more specifically, bodies of water that host a large population of pleasure craft (San Diego Bay, Marina Del Rey, San Francisco Bay) may have elevated levels of cuprous oxide, due to the anti fouling paints found on these boats. These may exceed federally allowed levels. This is the basis for any possible regulation in California.

[fstbttms]

Originally Posted by hellosailor

For now, the copper paint ban must go to California's Office of Administrative Law and the federal Environmental Protection Agency for approval.

To my knowledge there is no ban on copper paints in the works. The EPA has signed off on the TMDL for Shelter Island Yacht Basin. As I mentioned previously, this entails a drastic reduction in the amount of copper loading for that body of water, but how that reduction is implemented is up to the RWCQB- Region 9. The data the TMDL uses show that over 90% of the copper in the water is coming from passive leaching from boats in the marinas there, so logic dictates that the only way to reach the goal is to eliminate copper paint on the boats in SIYB.

[sluissa]

I'll be happy to see toxic bottom paints gone(simply because I hate sanding the stuff), but I really don't know about the price of the new non-toxic alternatives, I hope they come down to a reasonable price range.