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Roy M · 30-05-2013, 12:21

I'm hauling out tomorrow and will be the test dummy for a newly released copper-free bottom paint. It's called SEAVOYAGE, by Sherwin Williams, and produced locally in San Diego by Pro-Line Paints, an old, well established institution here. The Navy has been using the formulation here in San Diego Bay for the last five years and has been saying good things about it. It got its clearance from the State of California just three weeks ago. It is offered in only two colors, at the moment, with more to come as it gains acceptance. I am using the Black color instead of the red. It is a vinyl base, requiring a solvent thinner, and is supposed to provide greater coverage per gallon. I have been given two gallons to apply for the test, which is sufficient for my 40 foot Searunner trimaran. I currently have little or no remaining bottom paint on the epoxy graphite surfaced hulls, so I will be using an epoxy primer first. The active ingredient is zinc pyrithione (yeah, the same stuff as in Head & Shoulders shampoo). The natural source of the secret sauce is from echinacea (marigold flowers) and it has antibacterial and antifungal qualities. I'm told I should get about four years of protection from two coats on the bottom and a third at the waterline. With the speed of my boat, I should be able to give it a good test. I'll send some pics of the application process next week, as well as timely updates on its performance.

Kettlewell · 30-05-2013, 12:31

Neat! I hope it works out well. Can it be applied over old paint, or do you have to start with a stripped bottom?

Roy M · 30-05-2013, 12:51

In a quick read of the documents it appears able to coat previously leached bottom paint. When I'm back at the computer I'll send the full details. Right now I'm in the middle of preps to leave the dock. My application will be on a clean hull with fresh epoxy primer.

Teknav · 30-05-2013, 13:31

Zinc Pyrithione is effective against fungi/mildew and algae buildup because of its highly bonded sulfur content. It is used in soaps for skin dryness/fungal buildup and such. UV exposure will not affect it much. When it comes to fighting barnacles build-up on your boat's bottom, you will still need a copper based paint. Arsenic and copper are toxic to barnacles, hence they are in the formulations of many boat's paints. Mauritz

tamicatana · 30-05-2013, 14:08

prop and outdrive antifoul paints are zinc

Roy M · 30-05-2013, 16:57

As the wise guys say: "We shall see".

Here is the data: http://www.paintdocs.com/webmsds/web...prodno=N51B301

http://www.paintdocs.com/webmsds/web...prodno=N51R301

Roy M · 27-06-2015, 09:11

Well, it's been two years now using the copper-free SEAVOYAGE bottom paint by Sherwin-Williams. Much of it is now gone from the hull. but due to regular monthly cleaning by one of the most conscientious divers (Bruce of OMNI Precision Diving) in San Diego Bay, the bottom is in good, but needy, condition. I will be hauling out this summer to redo my bottom. My yacht club participates in a program to monitor pollution levels and ensure best marine practices by our divers. Our member that is involved in the study, a retired biologist and active sailor, has revealed to me that the current information regarding bottom paint now shows these copper-free alternatives to be of marginal value. This has been confirmed by Practical Sailor's 2015 test of bottom paints. In fact, their study shows ALL available bottom paints in the US (other than tributyltin) provide less than stellar performance. The best was rated POOR +.

So, fstbttms appears to be our most knowledgeable resource. What is your suggestion for a durable, long lasting copper paint available in California? I will be having it applied to both my forty foot trimaran, and a thirty-nine foot power catamaran recently purchased by a friend. Both boats will be making extended voyages in the next couple years to warm waters.