Hempel Calculator - Silic One specifically

[Tzu]

After a lot of research I'm sold on the Silic One route for my boat, utilising a tie coat as my existing antifoul is in a decent condition. Hempels calculator tells me I need 1 x 2.5l + 3 x 750ml. My question - buying 3 of the small tins would cost about the same as one large tin, for slightly less paint. I cant see any reason not to buy two large ones? It should seal ok for when I do the patches under the pads?
Planning on doing this in March when hopefully I will get a weeks worth of decent weather in one go.

 

[superheat6k]

Closely follow the instructions and especially the complicated application rules for variations in temperature and time between coats and it will work very well. For the top coats using two different colours makes this far simpler. Useless on props.

 

[scozzy]

Coverage calculators are obviously useful but also...well...a good guide if nothing else I suppose!


Preparation
Condition of existing surface
Ambient temperature
Application method

All these and more affect how far you'll get and like wallpaper...you always want to gave a bit extra!
Not like you won't/cant use the excess.

Long story short,always have more than enough

 

[Neeves]

If you apply a silicone coating and find, for whatever reason, that it does not suit (commonly - does not live up to the hype) then removing a silicone coating is difficult - and you cannot leave it and overpaint as nothing else will stick.

Use the Forum search function and you will find many have tried a silicone coating and reverted to conventional.

Jonathan

 

[[70521]]

As long as you have an average speed of >10 knots for 23 out of 24 hours per day it works. If not you might be disappointed.

One chap in the marina a few years back after an Atlantic circuit could not get it off the boat fast enough.

 

[Chiara’s slave]

As long as you have an average speed of >10 knots for 23 out of 24 hours per day it works. If not you might be disappointed.

One chap in the marina a few years back after an Atlantic circuit could not get it off the boat fast enough.

Me too. I bought a boat with it on. It was fine the first year, and would still be fine if I could have jet washed it weekly. But the spores got into it, and weed grew back in the 1st week after launch in spring. But a regularly used planing hull should be ok for it.

 

[Neeves]

Its been tried, silicone coatings - on commercial vessels, cruise ships + others, they are effectively used continuously and will travel at well in excess of 10 knots - many have reverted to conventional AF.

Maersk use Jotun's Sea Quantum (which comes in at least 4 forms, for ships laid up and speeds of upto 20+ knots). Conventional AF but for professional use only.

Jonathan

 

[mrming]

I have seen both poor results and a very difficult removal process with Silic One on a displacement racing yacht. I would not recommend it for any non planing vessel.

 

[westernman]

If you apply a silicone coating and find, for whatever reason, that it does not suit (commonly - does not live up to the hype) then removing a silicone coating is difficult - and you cannot leave it and overpaint as nothing else will stick.

Use the Forum search function and you will find many have tried a silicone coating and reverted to conventional.

Jonathan

So it is very effective for anti-fouling??

 

[AntarcticPilot]

So it is very effective for anti-fouling??

Only if the vessel travels above a minimum speed the majority of the time - as a cargo vessel does. The principle is that organisms that settle cannot adhere quickly, and are washed off. But if the vessel is stationary, organisms can settle and develop anchor systems, which defeats the antifoul.

Basically, only suitable for vessels that are in use most of the time, or that are taken out of the water when not in intensive use. The speeds involved are also too high to be sustainable by most sailing vessels.

 

[Neeves]

Most anti fouls, silicone or conventional, rely, to a greater or lesser extent on the flow of water, ie the vessel is used or it is cleaned with water at pressure, to remove fouling before it has time to adhere. Silicone has a surface to which it is difficult for fouling to adhere and the chemicals in conventional AF make it difficult for fouling to adhere and survive. Some conventional AFs have very strong chemical deterents to life (some are banned).

In terms of coatings that we can use - if you leave your vessel stationary, for not very long, then the surface collects slime, the slime allows fouling to gain a hold - and your hull will foul.

Silicone does perform 'better' as it does not destroy marine ecosystems but its not a panacea.

If you decide to slip your yacht and power wash the lifting straps can damage the silicone coating, its not very strong. Fouling will develop at the damaged area. If you hit something in the water when you are sailing the damaged portion provides a point where fouling can adhere.

Silicone is very difficult to repair.

If you want to revert to conventional AF then you need to remove all the silicone and it is almost impossible to remove the final few microns of silicone on the hull - conventional AFs will never stick.

If you don't believe any of this - find some silicone, the sort you squeeze from a silicon gun, remove the silicone - now try to have an epoxy resin attach to the cleaned silicone surface - not possible to achieve a strong bond unless you physically abrade and then wash with acid. You can source silicone removal product, nasty to work with, expensive, difficult to apply.

Look at the number of yachts with a silicone coating - that underlines the market penetration of silicone. Successful silicone coated yachts are like hens teeth.

Ask Hempel, International, Jotun about silicone coatings - they have all tried them. They do work - but not for the average owner (or they would be more popular).

The only successful use of silicone of which I am aware is Prop Speed, on running gear. Its expensive and is used in a very niche application - it does work - but has not gained very wide market penetration even on props. Interesting it has not gained wide acceptance on yachts and the treatment more commonly used relies on chemical AFs, namely Velox (use the search function of YBW to find threads on use of Velox).

Jonathan