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At haul-out time, my bronze prop is always full of hard growth around the center and out to about 1/3 of the way up the blades, even if I paint these areas with ablative anti-fouling paint (Micron-CSC). I'm guessing it's like this for the better part of the season as well. Data: Long Island Sound, 10" 2-blade prop, boat sits for as much as 2 weeks at a time during the summer without moving (I know, that's the REAL problem!!! :p )

It looks awful, but is it bad?

And if it is, what can I do besides diving in and cleaning it off by hand a few times a season?
 

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Petit makes a paint specifically intended for props to minimize growth - Petit Barrnacle Barrier paint - in a spray can and I am told my those who have used it that it works as well or better than anything else. My sole experience is using it last season for the first time and upon haul, the prop was FREE of any growth after 8 months in the water with little use.

Typical bottom paint is useless for and on props and could conceivably exacerbate electrolysis. If you want to try something, use the tool intended for that purpose.
 

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Another thing I have hear about but havn't heard any ones results is a product called Propspeed but it is expensive and a pain to put on your better off to try the petit stuff first.
 

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We've had similar issues with growth on our prop. Painting the bronze with Micron CSC does cut the growth to a good degree, but the paint wears off the tips of the blades too fast, and the remaining paint ends up in pitting the bronze because of electrolytic action: not good. We've also found that there's less growth when the zincs on our strut aren't replaced... The greenery seems not to like the galvanic charge-- but this also eats up the bronze. I had thought to simply spray paint the prop and strut with the stuff they use for outboards, but it calls for a special metal primer undercoat (yellow, IIRC), to isolate the topcoat from the metal underneath. This is actually what you should use before applying the Micron CSC anyway, so that's what we plan to do this spring. Luckily, we read the label on the spray can before deciding not to buy it.
 

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When I bought my yawl, the prop was crusty with barnacles. The Old Crank at the boatyard told me to leave the zinc off the shaft. He said that on the mooring, with limited electrical equipment, I wouldn't need it. He was right. I painted the prop with antifouling, left the zinc off, and had no problems with barnacles or electrolysis. I'm also in LI Sound. Maybe the paint didn't wear out because I rarely motor much, or maybe my prop rpms were lower.
 

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the zinc coat barnacle barrier would be better than the copper oxide based antifouling, regardless of brand. Who wants galvanic corrosion from disimilar metals?
 

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Propspeed is a very good product. It is very expensive, and very finicky application. If you go that route, it's one of those read the instructions two to three times, follow it to the letter, and apply once. Effective, expense, finicky application.
 

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Tartan 37C
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I applied Pettit's Transducer Paint to both my and my brothers running gear last spring at the advice of a local salt.



Was pleasantly surprised at how clean the prop & shaft looked on both the boats when we pulled in the fall. There was some growth, but it was minimal (6-10 small barnacles at most). Granted we are in brackish waters on the Chesapeake, but I will be reapplying it again in the spring.
 

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I applied Pettit's Transducer Paint to both my and my brothers running gear last spring at the advice of a local salt.



Was pleasantly surprised at how clean the prop & shaft looked on both the boats when we pulled in the fall. There was some growth, but it was minimal (6-10 small barnacles at most). Granted we are in brackish waters on the Chesapeake, but I will be reapplying it again in the spring.
I tried this on my bowthruster. I was hoping for a better result than what I got. Maybe a 25% improvement over doing nothing. My guess is that I simply don't use the bowthruster enough to knock off the growth in the early stages. Where, as the main prop is used quite a bit and the growth is an acceptable amount at the end of the season. I don't do a thing to the main prop. I think this year I'll just use regular bottom paint on the thruster.
 

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Propspeed is a very good product. It is very expensive, and very finicky application. If you go that route, it's one of those read the instructions two to three times, follow it to the letter, and apply once. Effective, expense, finicky application.
If you do you use Prop Speed and have a diver clean your bottom, be sure to alert him to it's presence. One swipe with a scrubber, steel wool or wire brush and your expensive prop coating is ruined.
 

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Aquaholic
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I have a slight topic diversion; but it's closely related so I don't feel too bad about hijacking.......

Background:

I am employed by a University doing marine research, recording whales and other marine mammals. One of the pieces of equipment I operate is a recording unit that floats a meter or so off the bottom, for about four months at a time, at depths from 10 to 150 meters.

I've been assigned the task of finding a material that we can apply to part of this equipment that will reduce the growth of fouling organisms; particularly barnacles.

The piece of equipment is made from 2" schedule 40 PVC drain pipe, with 1" holes drilled in it.

The Petit transducer spray, as well as the zinc barnacle barrier look promising; but I am wondering about adhesion with the PVC pipe.

Before I approach the manufacturer; do any of you have any ideas or observations that might be of use to me?

Thanks in advance,
Fred



PS: I'm posting this here because I believe in the collective wisdom of my fellow sailnetters NOT because my boss found me surfing the SailNet forum from work, honest. ( but it IS nice to be able to say I am legitimately working while on SailNet for a change!)
 

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Re: Is it bad,

as per a related thread the barnacle growth on the prop is significant for two reasons:
1) It can cause a vibration which can damage bearings
2) It can reduce fuel economy significantly

So hopefully one of the above mentioned products can help, if not I would scrub regularly, esp. if there is any vibration that you can detect
 

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Seinor Member
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You ain't gonna believe this

and to be honest, I am having trouble with it also. But here goes. Allot of cruisers at my marina,are swearing about Magic Marker. They get the large ones and give the prop about three coats after cleaning the prop. Oh they split the tube so they can apply it with the big wick.
It shouldn't work, in my thinking, there is nothing in it but pigment. As the snow birds return from the Bahamas this spring I will check out the props and let you know one way or the other.
If you see me selling a black product called Prop Magic for 10 bucks, you will know it works.

Fair Winds

Dave
 

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Pettit Zinc Coat Barnacle Barrier




It's working pretty well for me. This picture is after its applied, sorry I don't have one after the boat is pulled but I will take one this spring...

 

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Aquaholic
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why paint the shaft zincs?
You should not, as far as I recall

Nor should you paint before placing the zincs; you want to make sure there is good metal : metal contact between teh anode and the protected hardware
 

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I have a slight topic diversion; but it's closely related so I don't feel too bad about hijacking.......

Background:

I am employed by a University doing marine research, recording whales and other marine mammals. One of the pieces of equipment I operate is a recording unit that floats a meter or so off the bottom, for about four months at a time, at depths from 10 to 150 meters.

I've been assigned the task of finding a material that we can apply to part of this equipment that will reduce the growth of fouling organisms; particularly barnacles.

The piece of equipment is made from 2" schedule 40 PVC drain pipe, with 1" holes drilled in it.

The Petit transducer spray, as well as the zinc barnacle barrier look promising; but I am wondering about adhesion with the PVC pipe.

Before I approach the manufacturer; do any of you have any ideas or observations that might be of use to me?

Thanks in advance,
Fred



PS: I'm posting this here because I believe in the collective wisdom of my fellow sailnetters NOT because my boss found me surfing the SailNet forum from work, honest. ( but it IS nice to be able to say I am legitimately working while on SailNet for a change!)
It is my understanding that Pettit transducer paint and Pettit Inflatable bottom paint and Pettit Hydro-coat are all the same paint. They are water based anti-fouling paints that are safe for plastics. The others are solvent based paints. The Pettit Inflatable paint comes in Quarts and is more cost effective.
 

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Aquaholic
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Thanks Bubb; I think I'll try the transducer paint and see what happens. If it works well on the PVC; it might work for the next phase of this project, coating our acoustic hydrophone. (For this it would need to be mostly invisible, acoustically; which it might be close if it's designed for transducers.)
 
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