Antifouling the underwater metal

mattinri

Lieutenant Commander
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Jan 30, 2012
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Full time cruising
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Nordhavn 46
My Duffy 35 came up from Florida (to Rhode Island) with significant fouling on the underwater metal: Nibral prop (fairly clean), stainless rudder (a little more fouled), Bronze thru hulls, A skeg shoe (bronze or stainless?), dynaplate, bow thruster and the transducer face all fouled. Even have nice sized oyster tucked away in a few crevices. Once I chip and sand away the crud, what can I apply to keep it at bay in the future?
 

Reelaction

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On the metal components you could use prop speed but it is expensive. The ducer they make paint for. Or they make a epoxy for metal so you can paint over it.
 

Lion's Paw

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42 Duffy
I have been using a Pettit product, Zinc Coat Barnacle Buster, for the past couple of seasons and it is working very well. Seeing the bottom of the boat all the time I can watch it start to foul up. After a lot of use it will wear, but then everything I have ever tried on the metal does also and usually much faster than this stuff. I usually see no growth at all until late in the fall season, early spring haul. By next spring there is growth that needs scrapped, but I will sit for several months during the winter.

The prep is clean it to metal and put on one decent coat. Comes in a rattle can and is a bit pricey but holds up even on the props. I end up using alsmost three spray cans for the two shafts, rudders and props. It also works on the inlet strainers.

Only thing that ever worked better was a 5 gallon bucket of Sherwin Williams marine paint that had come from the US Navy surplus auction. That stuff stayed on and worked for almost two years before it wore off and nothing grew on it. If you find any majic stuff that works for extended periods, let me know!
 

MDI45

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I second the zinc coat barnacal buster.....i sprayed my rudder and stuffing box back in July....and i checked the running gear yesterday and it was spotless.....the stuff works good
 

Parttime

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Nov 8, 2012
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I have been using a Pettit product, Zinc Coat Barnacle Buster, for the past couple of seasons and it is working very well. Seeing the bottom of the boat all the time I can watch it start to foul up. After a lot of use it will wear, but then everything I have ever tried on the metal does also and usually much faster than this stuff. I usually see no growth at all until late in the fall season, early spring haul. By next spring there is growth that needs scrapped, but I will sit for several months during the winter.

The prep is clean it to metal and put on one decent coat. Comes in a rattle can and is a bit pricey but holds up even on the props. I end up using alsmost three spray cans for the two shafts, rudders and props. It also works on the inlet strainers.

Only thing that ever worked better was a 5 gallon bucket of Sherwin Williams marine paint that had come from the US Navy surplus auction. That stuff stayed on and worked for almost two years before it wore off and nothing grew on it. If you find any majic stuff that works for extended periods, let me know!

The Sherwin Williams is still available, I use it.
It's called Sea Guard Ablative and is available in one gallon cans.
 

mattinri

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Jan 30, 2012
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Full time cruising
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Nordhavn 46
The Sherwin Williams SeaGuard additive states it is a "polyamide polymer containing cuprous oxide. Recommended for the underwater surfaces of steel vessels." Cuprous Oxide is the same stuff in my regular bottom paint. Is that what causes the galvanic corrosion on metal?
 
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