A barnacle-free season, thanks to Petit 1792

[Joe Myerson]

On Sunday I started working on Creme Brulee. My first chore was to check out the prop.

Last year, based on advice from this board, I sprayed the prop with two coats of Petit 1792. I followed this with two coats of wax.

The results were extremely satisfying--the only place where a few barnacles managed to adhere was at the very end of the prop nut, around the cotter pin.

Some of the zinc coating wore away, especially at the leading edges of the blades. But, overall, it stayed on the prop--and the barnacles stayed off.

When I started sanding, I noticed that some of the wax also stayed on, which made the sanding a bit more difficult--but might have contributed to the longevity of the spray-on zinc.

As an inadvertent control, I can report that my Walker Bay 8 dinghy, which cannot be painted, but which I did wax, was covered with more barnacles and disgusting sea-squirts (tunicates) last year than in previous seasons.

This stuff works. Thanks, all, for the advice.

--Joe

[Emil Maurer]

Petit's Bulletin says : "Zinc Coat Barnacle Barrier's smooth hard surface will self clean in service." I thought that was like an ablative. I wondered how come you decided to wax it?

[Russell]

Just curious, how many hours did you put on your engine that season? I am wondering if heavy use would cause the coating to wear off and not be so effective. Though I guess as well there is the theory that heavy use prevents buildup as well, so I wonder if light use would allow build up or vica versa.

[Oswego John]

For many years we have been using Zinc-It , CRC and other zinc welding sprays on props and other exposed, underwater metals.

I don't know what Pettit 1792 costs. The zinc sprays we use cost between $12.00 and $13.00 for a 12 oz. spray can. Depending on which brand is used, they claim that the zinc content is as high as 94%.

The carrier dries very rapidly leaving a full coating of pure zinc. They recommend using no more than two coatings to prevent cracking

I don't know for sure but i would imagine that the zinc coating on the prop would provide some electrolytic protection as well as barnacle and grass protection.

The can is very heavy by volume. It must be shaken often to keep the heavy metal in suspension.

O J

[Joe Myerson]

Hi all,

Here are some answers to some of your questions:

1) Russell: According to my log book (I don't have an engine-hour meter), I ran the engine for 27 hours last season. Most of that time was getting to and from the mooring out onto Buzzards Bay.

2) Emil: I didn't read the bulletin, and probably should have. However, since I found that wax alone didn't keep off barnacles very well, I guessed that the wax would wear off, exposing the zinc, which would then do its own thing. It was nothing more than a guess.

3) OJ: I bought this product based on excellent results posted by several board members. There might be a nonboating product that does the same thing at a lower price--in fact, there almost certainly is such a product.

Also: I removed my shaft zinc before applying the zinc spray and wax. Then I reattached the shaft zinc--allowing it to be sacrificed as usual.

FWIW, the zinc coat with wax proved very effective last year. So, I'll probably give it a try again. (I had planned to have it done already, but I got hit with a fairly serious cold that is now abating--just as the warm weather also abates.)

--Joe