Zinc Chromate Paint and Barnacles 2022 results

[keneasley]

Lots of discussion over the years about this.

For the 2021 season I thoroughly cleaned the prop and drive shaft and roughed them up with a red scotchbrite pad. Then applied 2 coats of Rustoleum Zinc Chromate paint.
After 6 months in the water (saltwater harbor at the end of a slow-moving river) the result was not good.
Lots of barnacles and a very noticeable vibration and loss of power when motoring.

For the 2022 season I did the same but added a light coat of regular copper based bottom paint- Petit Hydrocoat. And I took a swim in August and used a metal scraper on the prop blades and drive shaft.
The result was very acceptable:

Prop_1.JPG (4.05 MiB) Viewed 715 times

Prop_2.JPG (3.22 MiB) Viewed 715 times

I used the boat and motor quite a bit - about 2-3 times each week and about 30 minutes of motoring each outing.

Not a direct comparison but here's a picture of the bronze grounding plate which only got the same paint but no August cleaning:

Prop_5.JPG (2.5 MiB) Viewed 715 times

Any thoughts on how best to paint and maintain the ground plate?

[Jim Walsh]

The grounding plate should be left bare. It’s made of sintered bronze and it will attract growth, but it must be left bare to do its job. Just give it a scrub, if possible, mid season.
Nearly every harbor has its unique environment so what works in one spot may be a disaster a few miles away. This season I just put a few coats of paste wax on my prop and it was only covered with some soft scum and a hundred pinhead sized barnacles. That was in seven months time. I only scrubbed it with a brush once in June.

[keneasley]

Thanks Jim. I'll strip the ground plate back to metal.
I'll plan on an annual prop and plate cleaning swim.
In our area the water temperature is very pleasant during August.

[jfischgrund]

I used the Rustoleum stuff last summer after a discussion of it on this forum, and it was not good at all. Maybe adding a coat of bottom paint on top of it will help, although I am considering going back to the Petit stuff despite its exorbitant cost.

[jfischgrund]

I used the Rustoleum stuff last summer after a discussion of it on this forum, and it was not good at all. Maybe adding a coat of bottom paint on top of it will help, although I am considering going back to the Petit stuff despite its exorbitant cost. Jim, what kind of paste wax did you use? Thanks!

[Jim Walsh]

I used the Rustoleum stuff last summer after a discussion of it on this forum, and it was not good at all. Maybe adding a coat of bottom paint on top of it will help, although I am considering going back to the Petit stuff despite its exorbitant cost. Jim, what kind of paste wax did you use? Thanks!

An ancient can of Johnson’s paste wax I found in my pantry. About as low tech as you can get. I couldn’t bring myself to using anything more aggressive on my new feathering prop. I’ll use the same thing this spring and hope for similar results.

[Chrisa006]

I have been using Pettit Barnacle Barrier prop paint both in Ct. and De. waters with good results. It is about $35 in a spray can. I have used it on both a fixed blade prop and my current Flexofold prop.

[John Stone]

Barnacles are a funny thing. I left my new high copper content flex o fold prop bare for two months in brackish water and it was covered in barnacles in two months. I stripped it and applied Petit Barnacle Buster spray paint and then sailed to the Virgin Islands. In 6 months I had nary a barnacle. Sailed back home and within two months it was heavily fouled again. Every place is different. Speed Prop coating is popular here with expensive power boats but it is ridiculously priced.

Paste wax eh? I’m up for for some testing.

[Jim Walsh]

Barnacles are a funny thing. I left my new high copper content flex o fold prop bare for two months in brackish water and it was covered in barnacles in two months. I stripped it and applied Petit Barnacle Buster spray paint and then sailed to the Virgin Islands. In 6 months I had nary a barnacle. Sailed back home and within two months it was heavily fouled again. Every place is different. Speed Prop coating is popular here with expensive power boats but it is ridiculously priced.

Paste wax eh? I’m up for for some testing.

A buddy of mine owns a big sport fisherman and he has tried everything over the years, including Prop Speed. The last time he had his props sent to a prop shop for a tuneup he decided to just put a couple coats of wax on them. He felt it worked as well as anything he’d tried over the years and has just used wax now for a few years. When he saw my new prop he recommended I just try the wax for one season. I just gave it a shot, seemed to keep most barnacles at bay for this season.

[John Stone]

Barnacles are a funny thing. I left my new high copper content flex o fold prop bare for two months in brackish water and it was covered in barnacles in two months. I stripped it and applied Petit Barnacle Buster spray paint and then sailed to the Virgin Islands. In 6 months I had nary a barnacle. Sailed back home and within two months it was heavily fouled again. Every place is different. Speed Prop coating is popular here with expensive power boats but it is ridiculously priced.

Paste wax eh? I’m up for for some testing.

A buddy of mine owns a big sport fisherman and he has tried everything over the years, including Prop Speed. The last time he had his props sent to a prop shop for a tuneup he decided to just put a couple coats of wax on them. He felt it worked as well as anything he’d tried over the years and has just used wax now for a few years. When he saw my new prop he recommended I just try the wax for one season. I just gave it a shot, seemed to keep most barnacles at bay for this season.

That's very interesting Jim.

[Steve Laume]

The Petit and Rustolium products are the same thing. If you are not having good results with Rustolium, spending more money for a different label will not provide better results.

I have been using Rustolium for a number of years. It is not going to stop all growth but it seems to work as well as anything. If the boat sits for a while there will be some growth. I dive on my boat and always scrub the prop first.

Wax is a great idea but don't know how well it will hold up for longer than one season. It might not like being scraped or scrubbed either. The galvanized paint is pretty hard stuff.

My prop is all painted and ready to go back on the boat but I may add a couple of coats of wax on top, this year, to see how that works out.

The plan is to go north next summer, so there may not be any diving but things tend to grow more slowly in cold water so it should work out.

[Jim Walsh]

The Petit and Rustolium products are the same thing. If you are not having good results with Rustolium, spending more money for a different label will not provide better results.

I have been using Rustolium for a number of years. It is not going to stop all growth but it seems to work as well as anything. If the boat sits for a while there will be some growth. I dive on my boat and always scrub the prop first.

Wax is a great idea but don't know how well it will hold up for longer than one season. It might not like being scraped or scrubbed either. The galvanized paint is pretty hard stuff.

My prop is all painted and ready to go back on the boat but I may add a couple of coats of wax on top, this year, to see how that works out.

The plan is to go north next summer, so there may not be any diving but things tend to grow more slowly in cold water so it should work out.

I agree, the difference between the Rustoleum and the Pettit product is the label on the can, not the product inside. The only reason I was willing to try the wax is because I have a seven month season in the northeast, primarily, and I’m frequently out sailing. I knock all the little critters off before they get too comfortable and invite friends and family for an indefinite stay.

[Walter Hobbs]

Tried the Rustoleum product again this season, had half a can left. Dove on the prop in July and had to scrape off barnacles. I think I'll try the wax this year, can't be much worse.