PBO Facebook Post - Antifouling Expert

[pyrojames]

Did anyone see and read this. Antifouling "Expert" Richard Jerram suggests that you should not put copper antifoul on a bronze propeller, as the it may create a galvanic cell that causes the bronze to corrode. He explains this in terms of the galvanic scale, and how zinc anodes will protect less noble metals. Fair enough. Except that in the case of propeller bronzes (manganese or NiAl Bronze) vs copper, there is little potential difference, and if any is to be expected, the bronze will be the more noble....

 

[Neeves]

Sadly those of us down under have not yet received a copy of any recent journal containing an article on AF and cannot comment (it might arrive here in a couple of months time). (I note, a bit tardily, that this was a Facebook post - not a communication medium with which I approve). Copper antifoul is certainly not recommended to be used on any propellor, bronze or not (bronze) if the propellor is attached to a. shaft protruding from an aluminium (are there non aluminium) sail drives. Without reading the article or post I thus cannot comment.

As an aside - I have never understood why sail drives are not made from a material other than aluminium say carbon/kevlar/glass reinforced resin - it would solve a lot of issues - but maybe there is a strong technical or commercial reason why we are blessed with the contradiction. We can buy polymer based props - why not a container for a sail drive.....?

Taking head of the warning, right or not, did Mr Jarram make a recommendation on which AF could be used that might be effective. It would be a major omission not to offer a sensible alternative.

We limped over to a beach only a few days ago with a badly fouled pair of props (and sail drives), beached the yacht, and spent time between the tides removing a small shelly reef. We had used Trilux (an AF focused at aluminium applications) and it was usuless and we will revert to Velox - unless Mr Jarram had a better suggestion.

Jonathan

 

[pyrojames]

Sadly those of us down under have not yet received a copy of any recent journal containing an article on AF and cannot comment (it might arrive here in a couple of months time). (I note, a bit tardily, that this was a Facebook post - not a communication medium with which I approve). Copper antifoul is certainly not recommended to be used on any propellor, bronze or not (bronze) if the propellor is attached to a. shaft protruding from an aluminium (are there non aluminium) sail drives. Without reading the article or post I thus cannot comment.

As an aside - I have never understood why sail drives are not made from a material other than aluminium say carbon/kevlar/glass reinforced resin - it would solve a lot of issues - but maybe there is a strong technical or commercial reason why we are blessed with the contradiction. We can buy polymer based props - why not a container for a sail drive.....?

Taking head of the warning, right or not, did Mr Jarram make a recommendation on which AF could be used that might be effective. It would be a major omission not to offer a sensible alternative.

We limped over to a beach only a few days ago with a badly fouled pair of props (and sail drives), beached the yacht, and spent time between the tides removing a small shelly reef. We had used Trilux (an AF focused at aluminium applications) and it was usuless and we will revert to Velox - unless Mr Jarram had a better suggestion.

Jonathan

Trilux was recommended. Something that I have not had much luck with!

 

[jwilson]

Did anyone see and read this. Antifouling "Expert" Richard Jerram suggests that you should not put copper antifoul on a bronze propeller, as the it may create a galvanic cell that causes the bronze to corrode. He explains this in terms of the galvanic scale, and how zinc anodes will protect less noble metals. Fair enough. Except that in the case of propeller bronzes (manganese or NiAl Bronze) vs copper, there is little potential difference, and if any is to be expected, the bronze will be the more noble....

Never studied chemistry, but this expert does not sound right, or if so only very very slightly right.

My prop which is bronze on a S/S shaft with bronze P-bracket with a shaft anode plus a tip anode has for the last 16+ years always had a coat of high-zinc primer paint followed by two coats of eroding copper-based AF. The prop is still there and showing no obvious signs of dezincification when sanded back to bare metal each winter. This treatment keeps it cleanish for 8 months a year. My test is full throttle gives 7.8 to 7.9 knots at full throttle in flat water out of tide on launch, by haulout time with no intervening scrubs it's down to about 7.5 to 7.6.

Before you ask, I have tried polishing to mirror shine ( fouled badly in months), and lanolin (even worse). Have not tried expensive "prop antifouls" as what I do works.

 

[vyv_cox]

Did anyone see and read this. Antifouling "Expert" Richard Jerram suggests that you should not put copper antifoul on a bronze propeller, as the it may create a galvanic cell that causes the bronze to corrode. He explains this in terms of the galvanic scale, and how zinc anodes will protect less noble metals. Fair enough. Except that in the case of propeller bronzes (manganese or NiAl Bronze) vs copper, there is little potential difference, and if any is to be expected, the bronze will be the more noble....

Yes, it was posted on Facebook, where I made similar comments. Unless the bronze component is abraded quite heavily Primocon will not achieve particularly good adhesion on it. An etch primer is far more effective. He recommended Primocon.

 

[Caer Urfa]

I have known Richard for some years when he was technical manager of International Paints and he sure knows what he is talking about

 

[vyv_cox]

I have known Richard for some years when he was technical manager of International Paints and he sure knows what he is talking about

No doubt he knows his paint but his advice here is not top quality.

 

[Sumara of Weymouth]

Trilux was recommended. Something that I have not had much luck with!

I've just used Seajet Triple Pack Propeller Antifouling. The primer was described as "superior to etch primers" in their details. I took the prop home for the winter and I am pretty sure I followed all the instructions ruthlessly but after only about two months it seems to be just flaking off. The prop is made from aluminium bronze.

 

[samsmarine]

Sadly those of us down under have not yet received a copy of any recent journal containing an article on AF and cannot comment (it might arrive here in a couple of months time). (I note, a bit tardily, that this was a Facebook post - not a communication medium with which I approve). Copper antifoul is certainly not recommended to be used on any propellor, bronze or not (bronze) if the propellor is attached to a. shaft protruding from an aluminium (are there non aluminium) sail drives. Without reading the article or post I thus cannot comment.

As an aside - I have never understood why sail drives are not made from a material other than aluminium say carbon/kevlar/glass reinforced resin - it would solve a lot of issues - but maybe there is a strong technical or commercial reason why we are blessed with the contradiction. We can buy polymer based props - why not a container for a sail drive.....?

Taking head of the warning, right or not, did Mr Jarram make a recommendation on which AF could be used that might be effective. It would be a major omission not to offer a sensible alternative.

We limped over to a beach only a few days ago with a badly fouled pair of props (and sail drives), beached the yacht, and spent time between the tides removing a small shelly reef. get all facebook status guide to this site and We had used Trilux (an AF focused at aluminium applications) and it was usuless and we will revert to Velox - unless Mr Jarram had a better suggestion.

Jonathan

Yes, it was shared on Facebook, and I left similar remarks there. Primocon won't gain very good adherence on the bronze component unless it is substantially abraded. Much more productive is an etch primer.

 

[vyv_cox]

Following my comments here and on Facebook, PBO asked me for a contribution on the topic of antifouling props. It is printed in the 'Experts' section of the December issue.