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Careful with that Silicone AntiFoul


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Apparently they knew it was a problem and were waiting for a crane when it fell so no one got hurt, must be very slick. Hope to try it out if it can be made smooth like paint.

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1 hour ago, Y88 5241 said:

We just anti fouled a boat with the Hempel Silicone Antifoul, very slippery stuff

how was it to apply and whats the finish like?

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4 hours ago, Y88 5241 said:

We just anti fouled a boat with the Hempel Silicone Antifoul, very slippery stuff

Really keen to hear your experiences with this....

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Application is by approved applicators (I work for Gloss Boats). Its a three day process to correct application but gives a very smooth and slippery surface. Longevity? Still to be seen however the manufacturer gives a very good warranty period.

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Its been around a while but maybe the price puts people off so not much feedback on a racing yacht. Have heard that its soft so easily damaged but IDK. Are you able to give us an idea of cost?

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44 minutes ago, Psyche said:

Its been around a while but maybe the price puts people off so not much feedback on a racing yacht. Have heard that its soft so easily damaged but IDK. Are you able to give us an idea of cost?

Approx 2.5x the normal AF costs

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I've been using silicone foul release for over 5 years now, started with soft coating since it was all that was available, now using a hard coating.

The soft coating was a nightmare to apply, and failed to live up to the durability claims. We were told we would get 5 years out of it minimum. It did it's job as a foul release, but wore so rapidly that we had to start considering replacing it after just over 2 years. Thankfully, that product is no longer available.

We've been using a hard coating now for about 2.5 years. It performs better all round. When clean, at cruising speed under power, we have about an extra knot over what we got with a clean hull and conventional antifoul. We have about an extra 0.5 knot over the clean soft silicone foul release. With one caveat, the product we are using seems pretty durable. We poke around in a lot of interesting corners that you really probably ought not take a 40ft yacht, so we "bump" the keel a bit, but never at speed. We don't seem to be losing much of the coating through this. 

The one caveat I mentioned is that when we had this product applied, we deliberately raised our waterline, so that out bottom coating now extends about 150mm above the actual surface level. We've found this year, in our 3rd summer with this coating, that the product above the waterline is deteriorating and breaking down. I think it is UV damage, and we're talking to the manufacturer about it. They have been very helpful. Below the actual waterline, no issues at all with deterioration.

Cost to have our boat done professionally and properly (sandblast back to bare metal, 1 coat expoy primer, 2 coats expoy immersion coat, 1 coat silicone), just under $8000 two and a bit years ago. 

And then of course, since it's a foul release and not an antifoul, you need to completely rethink how you manage keeping the bottom of your boat clean.........   And you need to have that clear in your head before you start down the foul release path.

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1 hour ago, AlastairW said:

And then of course, since it's a foul release and not an antifoul, you need to completely rethink how you manage keeping the bottom of your boat clean.........   And you need to have that clear in your head before you start down the foul release path.

What do mean by that?  I guess I do not understand the difference between foul-release and anti-foul...

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8 minutes ago, CarpeDiem said:

What do mean by that?  I guess I do not understand the difference between foul-release and anti-foul...

Antifoul has nasties in it that deters or kills the offending biology, silicone foul release doesn't. It operates like a non-stick frying pan, so the greeblies are washed off by the motion of the boat through the water.

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3 hours ago, AlastairW said:

Antifoul has nasties in it that deters or kills the offending biology, silicone foul release doesn't. It operates like a non-stick frying pan, so the greeblies are washed off by the motion of the boat through the water.

Does it actually self clean?  I've got MacGlide on my boat which is supposed to self clean, but it builds up a layer of slime which doesn't come off, even with a decent amount of speed.  I also find that the slime dries at the waterline which allows barnacles and such to get a foothold, it is very easy to clean though.

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I have discussed the Hemples silicon based AF in the past, but a bit too early for most, as it was once only available for Commercial applications here in NZ. As in, it was only imported in 44Gal drums and went direct to shipyards. It's great to see that has changed and is now available to the average boater.
As said above, it does not have Biocides in it. But the development came about for two reasons. Firstly for commercial, TBT was being phased out. Secondly, the Copper based AF's have had many of their ingrediants phased out from use and the performance of Copper Based is becoming poor. Thirdly, People are becoming much more aware of what we are putting into our environment these days. So for any Company that advertises they have a safer alternative, then they obviously will gain an edge in market share with their product.
As also said above, the slippery coatings DO NOT stop growth. But then, non of the Copper based Coating were doing that anyway. The only product that ever maintained a completely clean surface was the very expensive self eroding coatings that contain Hydrogen Peroxide. But they only last 12months.
The only down side of the Silicon coatings is that they do need a resonably fast hull for self cleaning. I think minimum was 12kts. That's is far above most Hulls. But they are easy to brush down.
The coating should last 5yrs because that is what they were designed for on Commerical Vessels. Commercial Vessels have to go through Survey every 5yrs. A Commerical owner does not want to have to haul out any sooner due to cost. On a Sailing Hull, there should be no reason what you cannot get 5yrs. If you were one that used the very first kind of non commercial products on the market, then you might not get 5yrs. Don't let that put you off on what is now available. The performance is improving all the time. After all, they are a very new and still developing product.
These products work in a similar way to Prop speed etc. They are still only available for commercial application due to 2 reasons. The product is sprayed on with a commercial pressure sprayer. Because it is silicon, that pressure applicator needs to be used for that product only. Anyone that uses these silicon products and then tries to spray a normal Paint coating on a Boat is going to be in for a big surprise. No matter how well they cleaned the equipment. The same goes for keeping any possible overspray from floating arund in the air. A microscopic spec of silicon on another surface is a nightmare when it comes to painting. Even the materials and equipment used on preparation of the Hull before recoat needs to be kept separate from normal paint handling areas. Or at least, it is wise to anyway.
The only downside I see to it is the cost. It might be OK when viewed over 5yrs, but it's a big chunk to have to find every 5yrs.

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1 it seems like a very round number

2 for most of us, who trundle around near hull speed, where hull speed is in the region of 7 knots, an extra knot feels like it's going to require some magic wave drag supression

3 has it become completely impossible to compete in racing without silicone af as this suggests? News to me.

 

Still interesting though.

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15 hours ago, Dave said:

Does it actually self clean?  I've got MacGlide on my boat which is supposed to self clean, but it builds up a layer of slime which doesn't come off, even with a decent amount of speed.  I also find that the slime dries at the waterline which allows barnacles and such to get a foothold, it is very easy to clean though.

Dave, the stuff we have (Seaspeed V10x) self cleans reasonably well as long as you are using the boat a lot, and don't give the slime a chance to get a hold. But once any fouling gets a hold, it gets more difficult. With the slime, we find that if we get out in a decent wind and a bit of a seaway, when we come back in again, we can see where it has started to wash off. We have dirty slime down here.......  Leave the boat sitting on the berth for longer than a few weeks though, and it gets harder. Washes off really easily though when I get physical with it.

I took the boat out of the water in February and cleaned it thoroughly. Went off down to Stewart Island till the end of March. When I got back to Dunedin, the bottom was still spotless. I wasn't moving her every day while there. but often enough to keep her clean. Back on the berth in Otago Harbour, and within 3 weeks of not moving, and the slime built up. Otago Harbour has become a lot more weedy/fouly in the past couple of years.

I know exactly what you mean about the barnacles, and it will be the same for long weeds etc too. We haven't had an issue with those for a couple of years now, we use an ultrasound unit to manage those.

 

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38 minutes ago, SloopJohnB said:

And lose all the advantage with a couple of bad tacks.😉

hehe, it just means I don't need to work on my tacking!

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