SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

To paint or not to paint (prop)

4K views 23 replies 15 participants last post by  Delta-T 
#1 ·
I have been painting, with bottom paint, my prop for the last 30 years with no loss of performance. I see in the yard that some paint and some don't. I would think with a low RPM of a sailboat prop that this is not an issue to paint. Just wondering what you all think about doing it? I see lots of barnacles on unpainted.
 
#2 ·
It's something we're going to do before we launch in the spring. I hadn't given it much thought until this year when we had the uber-barnacles. Our slip neighbors paint their own and I'm going to use whatever it is they use if it's appropriate for our prop.
 
  • Like
Reactions: Delta-T
#3 · (Edited)
I see lots of barnacles on unpainted.
That depends. There are props made in many kinds of material: Steel, Alu, stainless, bronze, brass, plastic (many outboards, Kiwiprop as well), and more.

Of these, if bronze or brass are left unpainted, there wil not be any barnacles. The Cu will stop that.

There is then of course the condition that brass props must have a zink anode (in salt water). Different types of brass, some are called DZR, which may not need an anode. Anyhow, brass with an anode, barnacles will grow.

Most sailboat propos are in brass, some in bronze.

Some conclusion could be:
- bronze propos don't need to be painted, don't need an anode. No barnacles.
- "all" others need paint, otherwise barnacles.
- brass needs anodes. Then paint as well. DZR is doubtful, why take the risk?

/J
 
#8 ·
I got no room for zink. No exposed shaft...1/2" maybe. But I have never heard of the zink being for barnacles. I thought the zink that I have in my engine head it to help with metal degradation from the water.
 
#10 ·
I have painted my prop with bottom paint for years and it fouled a bit with barnacles at about the same rate as the hull. Last year I read somewhere (Mainesail advice? this forum? another sailing forum?) that Pettit Zinc Coat Barnacle Barrier spray paint (93 percent zinc) applied to a bare prop would keep a prop clean and eliminate prop deterioration due to de-zincification of the bronze. I used it prior to launch this spring. My prop is clean as a whistle 6 months later with no brushing needed. Jamestown distributors was my source (not affiliated) - $24.96 currently - if you don't have a local source (special shipping fee applies). Easy to apply. Probably enough in the can for 5-6 prop treatments for a 30 footer so you can share with your friends or save the leftovers for re-coatings during haulouts.
 
#12 ·
That Lanocote option? Doesn't work in the Chesapeake. I can't wait to haul so I can spray that special prop paint from Petit. I had used that stuff before with success. Doesn't last forever but is better than the alternatives.

Tod
 
#13 ·
The PO of our boat told us he uses the Petit spray paint that people have mentioned. When he told us what still needed to be done for spring, he didn't mention the spray paint so I thought it had already been done. My bad. We've cleaned the prop by hand three or four times so far this season.

Next year we'll definitely be using the Petit paint.
 
#14 ·
One thing is for sure, barnacles grow on bronze. I have had a ball of them so big I could barely push the boat through the water. Two years ago I used the petit (thank you Maine Sail) and just last month had to knock some barnacles off the prop. I wish I could spray some on underwater. It's good stuff, and don't go the cheapie rustolem route. It is just not as good as the Petit.
 
#16 ·
If you get Barnacles... and Delta-T you will (I know because I was in the slip directly across from you when you were on B dock) you can dissuade them with what is commonly known as transducer paint. You will still get some, but it will take them longer to get a foothold.

DO NOT paint anything bronze with copper based paint, as it will leach out the zinc from the bronze, and you will find yourself buying new struts / props as they become brittle and break.
 
#17 ·
If you get Barnacles... and Delta-T you will (I know because I was in the slip directly across from you when you were on B dock) you can dissuade them with what is commonly known as transducer paint.
If you go to the Pettit web site and compare the transducer paint and barnacle barrier you will find that they are VERY similar. I think (but don't know for sure) that the barnacle barrier is simply the transducer paint re-packaged to highlight that purpose. Both are 93 per cent zinc in a fast drying solvent base.

Transducer Paint
 
#21 ·
So are you all saying the zinc content of the paint protects the metal from dezincafication and, if room permitting a zinc attached to the shaft doing the same. I understand that, but how does that deter barnacle growth? And did they not decrease the copper content the the new bottom paints?
 
#22 ·
I had been a fan of the Pettit Zinc Coat Barnacle Barrier and had good success for several years, but not this year. Seems nothing was working around here except scrubbing.

Good to know there may be a less expensive alternate, but really I think I pay about $20 for can that I can get two applications from (2 years worth of paint), hardly a wallet burner :)
 
#23 ·
Keep in mind these pictures were taken a few years ago...

This photo of the prop was taken just after haul out, about 8 months in brackish water (Patapsco River, Chesapeake Bay), average season for growth



and the shaft, not sure why the shaft had significant more growth, both prop & shaft are SS, both applied with Pettit Zinc Coat



BTW, this is a bottom paint photo, Pettit SR40

 
#24 ·
I was in the same slip for over 20 years. Used to be at low tide I was sitting on the bottom in my self made cradle. And after they dredged to 8' deep the difference was night and day. Only a hand full of barnacles now.

I may have miss spoke what I use on my prop for paint, as seen in my pics. I use a underwater metal primer (almost a rubber coating) then coat with bottom paint. 44 years...no zinc and painted. At 1200 rpm for less than 30 hrs a year avg use, I am not asking the prop to do much. I sail as mush as possible and thank the heavens every time she starts up. You know you have been on one boat for a long time when you have rebuilt most everything at least 4 times.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top