Sail Drive Antifoul

[Dobbies]

Sorry to raise this weary subject again.

When my boat was lifted last winter 2015/16 the boat yard maintenance crew managed to scrape through the sail drive paint revealing the base aluminium. Before relaunch I prepared it using Trilux Prop 0 Drev primer and antifoul. However this is what it looked like when I lifted her this winter:



I moor on a swinging mooring on the Fal river in Cornwall which is tidal, and I sail around 5 days a week, so she's never idle for too long. On the other hand I painted the hull with Hempel Tiger and that was clear of beasties and just slimy.

Looking at the results it seems a little pointless me spending a small fortune on a folding prop last year!

Anyone got any ideas or a better solution?

Cheers
Bob

 

[Lucky Duck]

Ouch, what was the hull like?

 

[Chi34]

A copper free antifoul for the leg should be OK, I think.
I have no idea to keep a prop clean.

 

[richardbrennan]

I've always used Trilux, but the paint rather than the spray for the saildrive, and Dr Barnacle's Grease for the prop which is a Volve folder, and have always had fairly good results with just slime on the leg and a few bits of animal life on the prop. this is n portsmouth Harbour which is considered a high fouling area. I am not sure whether the paint and the spray are the same thing, but I think I would send your picture to International and see what they have to say; like Little Grebe's prop, you might have got a bad batch.

 

[Dobbies]

Thanks Guys,

I think I'll take Richards advice and try the Trilux paint and Dr Barnacle's Grease this season. I must admit this is the worst build up of sea creatures I've encountered on my boat since I've own her.

Cheers
Bob

 

[ostra4]

Iv been using velox plus on my yanmar sail drive , it's very expensive but very effective , the sail drive comes out of the water looking the same as when launched six months ago , I can't belive how good it seems . A small tin was 24 euro in Greece but it's done three seasons so far and just about enough for this coming year .

 

[Bav34]

Trilux Spray. North Brittany and Channel Islands. Boat in commission all year.

Might just as well use a cheap emulsion :disgust:

 

[richardbrennan]

Hi Bob

Just to fill in the detail; I usually antifoul in May and have a quick lift out for a scrub and prop clean, when I re-apply the grease to the prop, in late October or early November.

Good Luck

Richard

 

[Dobbies]

Hi Richard

Thanks for your input.

I'm about to order International Trilux 33 paint, but before I do and as I used Trilux spray primer & AF last season, will I need to apply another primer first?

Cheers
Bob

 

[Halo]

Personally I would go with Velox. If Trilux did such a poor job in your area I think an alternative must make sense

 

[Dobbies]

Personally I would go with Velox. If Trilux did such a poor job in your area I think an alternative must make sense

Using Velox on the sail drive, would I first have to remove last years trilux AF & primer, or indeed need to go back to bear metal?

Cheers
Bob

 

[philwebb]

Hi I've got the same setup as you. I'm moored in Portsmouth harbour all year. I'm using Mille drive spray 3coats. It's not perfect but it seems to keep most of the greenery off. I've tried Lanocote on the prop but it washes off in use. If you spray don't forget to mask up the anode.

 

[richardbrennan]

Hi Bob

I am afraid I cannot answer your question regarding a primer as I put the Trilux onto the original saildrive paint although I seem to recall that I was advised to abrade it first which instantly trashed the warranty. To be on the safe side, and assuming that your current paint is OK when you remove the mussel farm, I would put on a coat of Primacon to be on the safe side.

 

[ostra4]

If you go on the velox website there's a very informative write up on preparing the surface , I followed this the first year I used Velox and now I give the saildrive a light sanding before re coating and that's it .Were based in Med , the first couple of times a had a look at my saildrive in water after a month or so I could belive what I was seeing .. Or not seeing as in no growth whatsoever . Justifies the very high price I suppose .It's here
http://www.marlinpaint.com/wp-content/uploads/VELOX_LEAFLET_ENG_2013.pdf

 

[maby]

The waxy prop treatments seem to be very successful while they last, but that seems to be less than a full year. Application is important - follow the instructions carefully.

 

[Harry Brown]

I'm just about to antifoul the Saildrive myself.
Can I just confirm that you should sand to bare metal, prime them paint (Trilux for example)?
I thought that the aluminium had a few micron protective treatment and therefore sanding would be a bad idea as you would remove this protection?

 

[maby]

I'm just about to antifoul the Saildrive myself.
Can I just confirm that you should sand to bare metal, prime them paint (Trilux for example)?
I thought that the aluminium had a few micron protective treatment and therefore sanding would be a bad idea as you would remove this protection?

Aluminium in air does have a thin oxide layer that is very resistant to corrosion, but I don't think you can rely on it in salt water. It is also not a good base to receive paints and I think you would find that all your anti-fouling would fall off pretty quickly if you applied it to bare aluminium alloy. The correct treatment is to get it decently clean, then apply an etching primer as the first layer. This is moderately acidic and will remove the oxide layer before reacting with the surface of the metal to bond in with it. Then you can finish off with your choice of paints and anti-foul.

 

[Skylark]

I had contradictory advice when I bought a new boat with Yanmar Saildrive. The dealer did not antifoul the leg and when I queried it (at first haul-out, 3 months after launch) they told me that Yanmar did not recommend it. My manuals are on the boat but iirc they state that the leg can be anti fouled.

I rubbed down the leg and used Primocon and Trilux 33. It has been quite successful. At the start of a new season I'll rub down the leg and "refresh" the Trilux only.

My biggest problem is removing sea squirts from the gap between the hull in-fill and the top of the Saildrive.

 

[Halo]

As above if you expose bare metal you need to etch prime. Etch prime requires decent temperatures and care. If there is only a small bare patch I would prime with hammerite special metals primer as it seems to work as well as anything and is much cheaper.

 

[maby]

Well, etching primer is certainly more expensive than a can of simple paint, but in the context of a boat it is not ruinously expensive. Halfords will sell you an aerosol of etching primer for £16 - the antifoul you put over the top will be significantly more expensive, so the primer seems like a good investment if it keeps the antifoul on!

P.S. in response to Harry's question above - if the primer and paint layer is in good condition, there's no need to remove it but if it is flaking, it should be either completely removed and repainted, or at least well patched up.