Experiences with Silicone 'antifouling' like Silic One from Hempel

[Ilona]

Hi everyone,

For our new boat, we're looking for a better solution for antifouling. I'm interested to find opinions about a Silicon based product like Silic One from Hempel. Anyone here who tried it and wants to share the experience? I couldn't find anything on this forum yet. I think the concept sounds interesting but I'm afraid to go for it without doing decent research.

Very curious whether someone knows more.

Thanks for sharing in advance

Cheers,
Ilona

[Ilona]

Is there really nobody who has any information regarding this topic? It sounds so ideal, I would think more people would be interested?

OK, and if you don't have personal experience, maybe you've seen it on a boat from someone else?

Anyone?

Originally Posted by Ilona

Hi everyone,

For our new boat, we're looking for a better solution for antifouling. I'm interested to find opinions about a Silicon based product like Silic One from Hempel. Anyone here who tried it and wants to share the experience? I couldn't find anything on this forum yet. I think the concept sounds interesting but I'm afraid to go for it without doing decent research.

Very curious whether someone knows more.

Thanks for sharing in advance

Cheers,
Ilona

[Snowpetrel]

I'd like to know more as well, I guess it is similar to propspeed?

[SnakeEyes]

About 2:30 into the video

https://www.youtube.com/watch?v=m-9eFsCFCLY

[Ilona]

Originally Posted by SnakeEyes

About 2:30 into the video

Hey, thanks! That's interesting to see! Thanks for your efforts, great.

If someone has yet another video or info about Silic One or similar, It'd be good to see/hear.

Cheers,
Ilona

[Al Walker]

We put Aqua Cote onto Wild Bird a year ago (42ft steel medium displacement yacht). Our experience is that as long as you keep the boat moving regularly, it will stay clean. We had a fairly bumpy trip in her in November, there was a bit of grass growing before we let, by the time we got back, all we were left with was slime.

However, a couple of months over the Summer sitting on the wharf in the boatyard, and she's pretty gross, to the point I'm going to put her onto the cleaning grid on Friday for a scrape.

The guy who checks our mooring had a wee rub at the hull, and reckons that despite the growth, it still comes off very easily.

I think the secret is to keep the hull clean by using the boat lots !!

I also found that under power, we gained close to a knot in speed at cruising revs.

If the product has the long service life claimed, then I feel it'll be worth while, but only time will tell with that.

Also, double check quantities required, we ended up using almost twice as much as the agent said we'd need, but when we worked it out for ourselves, what we used was pretty much in line with the manufacturers data sheet.

Takes a wee bit of a change of mindset to go this way.

[Snowpetrel]

^^ very interesting Al. I'd love to hear more about that aquacote,

How much did you use.

What was it like to apply, and what sort of substrate pretreatment was needed?

Why do they say it is only good for up to five years?

What is it like to remove and recoat after it loses its effectiveness?

What sort of cost was it in NZ?

Cheers

[Al Walker]

Hi Ben

The agent recommended we use a 3 litre kit, we ended up using 5 litres, which was pretty much what it came out as when we worked it out from the data sheet after the event.

We took the below water hull down to bare steel, a couple of coats of good epoxy primer, then into the AquaCote. There are two coats associated with that, a vinyl base coat which has the colouring in it, then the silicone top coat. Has to be rolled on, can tell you a lot more about that if you go down that route.

The cost here was about $900NZ per 3 litre kit, we got the boatyard to apply it for us - took them a bit more than half a day for each coat. You could easily do it yourself once the primer is on.

They state a 5 year life so that their backsides are covered. The agent was telling me that there are yachts here which have had the coating on for 8 years and still no trouble.

Had a good chat with the boatyard painters about removal/recoating. They think, based on how we handled a small hiccup, that you ought to be able to recoat on top of the silicone after a good roughing, and thorough clean with a light solvent cleaner. Would need to be thorough though. We did that after running out of product, and there is no sign of lifting. Removal of the coating would be a heavy garnet blasting job.

I understand that the AquaCote parent company in the UK went through some financial difficulty, and that product is not currently available, but International actually make a foul release specifically for slower boats now, which only need you to be going over a couple of knots for it to work. We find we need to either be in a heavy seaway, or be going over 6 knots with the AquaCote.

I'll let you know what it looks like after I put the boat on the drying grid on Friday.

Al

[Snowpetrel]

Thanks Al, excellant info. I am not quite ready to strip off all my antifouling and start again, but it sounds like these paints are becoming a viable option, especially for aluminium boats and low fouling areas.

[BlueChicago]

I have been interested in what seems to be a similar product called Neosil by Dutch Durable Coatings. I wonder if anyone has any experience with this product.

I am having my hull peeled and epoxied, so I find this thread especially interesting.

[Ilona]

Originally Posted by Al Walker

We put Aqua Cote onto Wild Bird a year ago (42ft steel medium displacement yacht). Our experience is that as long as you keep the boat moving regularly, it will stay clean. We had a fairly bumpy trip in her in November, there was a bit of grass growing before we let, by the time we got back, all we were left with was slime.

However, a couple of months over the Summer sitting on the wharf in the boatyard, and she's pretty gross, to the point I'm going to put her onto the cleaning grid on Friday for a scrape.

Thanks for sharing!

Where are you located?

I'm really interested to know whether you can just wipe the growth off with a sponge. I don't care to clean the hull since we're going to go to the tropics and will be in nice waters but it really would be nice to just wipe instead of scrape, just to preserve the paint.

The guy who checks our mooring had a wee rub at the hull, and reckons that despite the growth, it still comes off very easily.

Let us know how you find it Friday? Check whether it comes off simply by wiping? And of course whether the layer looks still good.

I also found that under power, we gained close to a knot in speed at cruising revs.

Compared to a clean boat with another antifouling? Or compared to when the boat had (a bit of) growth?


Thanks again Al! Good info

[Al Walker]

Hi Ilona

We are located down in the South of the South Island of New Zealand, once upon a time was a reasonably low fouling region, but the seas have warmed up, and we do get considerably more growth now.

When I mention scraping, I'm being a bit dramatic. Grass, weeds and slime come off easily with a rub using an old towel or similar, barnacles etc are a wee bit more tenacious, but will still come off with a slightly harder rub. No big deal. I think that most of those silicone foul release coatings are fairly resilient, so rubbing them doesn't really do any appreciable damage.

That increase in speed was over our boat with a clean bottom. It was something we were told before we put the coating on, I was a bit sceptical, but there you go.

Will post again at the weekend and let you know what the bottom looks like

Al

[Al Walker]

So, back by popular demand........

Ilona and Ben, put The Bird onto the drying grid yesterday and gave her a good clean. Bear in mind this is a foul release we are talking about, not anti foul, so needs a wee change in mindset.

As I suspected, there was much growth below the waterline. Looked more like a shag-pile rug......... The hull was pretty clean in November, but then we spent 2 months alongside in the Carey's Bay boatyard, right beside the container/logship/cruiseship berths, in warm dirty water, and nature took its course. Some interesting looking organisms there, but that would be thread drift. Anyway, despite the degree of growth, some not too energetic scraping with a plastic scraper (the sort you would use for de-icing car windows) took the growth off easily. Even the barnacles and other shelly greeblies. They just cannot get a good grip on the silicone coat. No apparent damage to the coating either. I gave the waterline area a wash off with weak bleach solution as well, and that got rid of some other goo that wasn't responding to the scraper (would have been fine with a more flexible scraper).

I did actually manage to hose off some of the growth with a high pressure hose (not water blaster) before the tide went out enough for me to get to the hull.

Now, I made all this hard for myself by neglecting the boat for a number of months, and choosing a time with minimum tidal range, to the stern didn't come right out of the water, but even so, I was able to clean the entire boat in about 2.5 hours.

When we had been using the boat most weekends before November, the hull remained pretty clean. and in this state, I reckon that a quick dive on the boat with a cleaning mitt or a towel, would be all that is needed every few months. As it turned out, given the general ease of cleaning, I'm not disappointed with the product.

There doesn't appear to be any damage to the coating, the only issue I found was one wee area on the bottom of the hull just above the prop where the growth was harder to remove. I suspect that the painters might have had a wee holiday there, and have missed that bit. Not a large area, I'll put some more silicone onto it next time I have her out on the grid again.

Performance in the water is back to where it ought to be again. Clean hull with antifoul, at cruising revs we would make 5 knots against the tide in Otago Harbour. Last night going back onto the mooring, touching 6 knots.

Talking to Kevin Of The Moorings yesterday, his motor launch has a Coppercoat bottom, and he has to bring that out of the water every few months to remove slime and burnish the coating as well. He has a 30ft launch, and that takes him longer than it took me to clean a 42ft yacht.

Since I don't like swimming much, I think my strategy in the future will just be to put the boat on the grid and hose it down every few months.

Any questions, just shout.

Al

[Ilona]

Great Al, thanks for your thorough response!

Interesting to read about all this. Also about the time it took you vs the time it took the person with a much smaller boat with coppercoat. Is the coppercoat about the same state/age?

Did you try a soft brush for cleaning? I've been told this works well but that was by the manufacturer.

Cheers,
Ilona

[Al Walker]

Something soft would have worked had I not let the fouling get so bad. But the hard plastic scraper I used didn't seem to damage the coating - not that I could see anyway.

Coppercoat is a very different strategy. It is an antifouling coating, with copper flakes embedded in epoxy. I didn't fancy using it on a steel boat, although it is said to be safe to use on a steel boat. I think it had been on Kevin's launch for about 2 years.