Look at Intersleek 1100SR. It may be updated by now under a different name. My diver says it's the best bottom paint he's ever seen. Yes, a barnacle will stick to it, but he says you can flick it off with your finger and no husk is left behind without scrubbing (unlike most other bottom paints). It too would be a problem to remove or paint over. I didn't switch because the product and primer has to be bought in 5 gallon quantities. Watch it in action here
https://youtu.be/qPwyjCauoDE and
https://youtu.be/rjWv6YFsfYA Note that the growth may not come off just by motoring around, particularly for a slow sailboat or trawler.
Look at Intersleek 1100SR. It may be updated by now under a different name. My diver says it's the best bottom paint he's ever seen. Yes, a barnacle will stick to it, but he says you can flick it off with your finger and no husk is left behind without scrubbing (unlike most other bottom paints). It too would be a problem to remove or paint over. I didn't switch because the product and primer has to be bought in 5 gallon quantities. Watch it in action here
https://youtu.be/qPwyjCauoDE and
https://youtu.be/rjWv6YFsfYA Note that the growth may not come off just by motoring around, particularly for a slow sailboat or trawler.
Great clarification that I was about to add as well Stinkpotter. As a former auto and antique car painter, I can relate to the problems most mentioned above that stray silicone can create all sorts of problems when repainting. On sprayed on finishes this most commonly results in lots of random "pock marks" in the surface finish that are difficult to get rid of afterwards. Additives have been developed to resolve this particular problem, which usually involve just adding a few drops of silicone to the paint in your paint gun which causes the paint to flow evenly. However in the case some mention of having removed silicone based caulking and then finding the invisible silicone residue left behind or spread out on other surfaces making it difficult to impossible to get new caulking or paint to stick.
However the OP was asking about using a silicone based product for BOTTOM PAINT, and this is an entirely different situation and one I can personlly recommend VERY highly. On our recently launched (Feb 2021) new all aluminium XPM78 boat Möbius, I had intended to use CopperCoat but after several conversations with builders of commercial metal boats both steel and AL, the majority were using what is referred to as Foul Release bottom paint as opposed to Anti Foul type paints used most commonly on recreational boats. So I decided to go with a Foul Release paint instead and chose International’s InterSleek 1100SR. These silicone based Foul Release paints takes a “non stick” approach rather than chemicals that deter growth as in the case of Anti Foul types of bottom paint. To the best of my knowledge all the Foul Release paints available from the likes of International InterSleek and Hempel Silic One are silicone based and every similar to that of prop paints such as Prop Speed. These silicone based paints work as you might expect, similar to say Teflon, they provide a surface that is difficult for anything to stick to.
It is true that the ideal scenario for these Foul Release paints is on boats that are in constant use and regularly run at speeds above 12-15 knots as these speeds through the water is usually enough to dislodge any growth that might have occurred while the boat was sitting still and as such they would be “self cleaning” and require little to know maintenance. When I spoke with captains of Coast Guard, Navy and very large container ships and such, they loved the stuff as it did just that, required pretty much no maintenance to the bottom as it stayed clean all the time and lasted them 4-8 years between recoating. But these ships have a very different use case where they are only ever still for a few days at most and then underway for many days/weeks at speeds around 20 knots. What about the rest of us?
What I discovered and was mentioned above is that if your boat is not being moved for longer periods of time and does not regularly run at 12+ knots then yes, there will be some growth visible on a Foul Release or silicone based bottom BUT this growth comes off with very little effort or force and makes cleaning the bottom a very fast and easy process. In our case I only have about six months of in the water use to go on but so far I have been just blown away by the performance of our InterSleek 1100SR. The boat sat unmoved for about the first 4 months while we were completing the build and doing the commissioning, at which point we hauled out for a few weeks and were able to see what had been going on in that four months time. On the InterSleek bottom surfaces there was a thin layer oof some growth over the surface of the bottom and there were a few barnacles on the InterSleek and on the PropSpeed coated 4 blade 1m CPP prop blades. A few days after hauling out, my wife and I started by taking a bucket of fresh water and a sponge and we wiped the InterSleek surfaces with the now dried on growth and it all came off in one gentle swipe. No scrubbing and nothing more than the same way you would wash the dirt off your car with a sponge. Soft rags worked equally as well. No scratching or abrading of the InterSleek at all and we were left with a new sleek shiny surface again. And those barnacles? As StinkPotter mentioned above, these too either came off with the sponge or a quick flick with your fingernail leaving no trace behind. In the two months since we relaunched and the boat has only been on three or four day runs, there is little to now visible growth and if I just use my bare hand to rinse off the bottom paint above the waterline on the aft end of the swim platform, the bit of slime there also just rinses right off and I’m back to like new shiny Black InterSleek.
I can’t attest to it yet, but many of the same captains I talked to with Foul Release bottom paint said that they were also picking up around 10% less fuel usage due to the slicker bottom surfaces. I’m not sure how scientific their claims are but it does make sense that these silicone based bottoms would have less drag and could therefore require less power for the same speed of a given hull.
The next few years will be the bigger determination of just how well our InterSleek Foul Release holds up and performs in different waters, temperatures, movements, etc. but based on our first six month experience this is by far the best bottom paint situation we have had in all the decades we have been out sailing the world on our previous boats. We are accustomed to cleaning our own hull bottoms after being at anchor for longer times and before longer passages and our expectation is that we will continue to do so with this new boat and its new type of bottom paint. But, based on our initial experience this will be a piece of cake to be able to just wash the bottom with sponges and rags vs scraping our typical non-ablative Anti Foul and will dramatically cut our total time underwater and effort involved. This much lower maintenance along with much slicker bottom and the most environmentally friendly option I know of is a huge benefit to us. I will continue to report with articles on the Mobius.World blog as to our real world performance of this paint as we get back out there cruising the world full time.
Right now though, our Foul Release InterSleek 1100SR gets two huge thumbs up from us!
