vanoord
Member
White antifouling is an odd one...
On the plus side it is often the best colour on powerboats with a gelstripe as it doesn't clash.
But, white has a few downsides:
- Because the base, uncoloured antifouling is a brown sludge, a white antifouling will contain a lot more dye than other colours, hence it tends to be weaker. We tend to apply an extra coat of white compared to a darker colour
- Similarly, it is very difficult to get a very white sort of white: most whites are light grey
- Once launched, copper compounds (in particular) leach out and can stain the antifouling green
In terms of how an antifouling works, even a hard antifouling has to erode in order to work*: this exposes fresh algicide to give protection throughout the season. Thus, if you scrub an antifouling, flakes will fall off.
In general, a powerboat will require a 'hard' antifouling, which is more resistant to erosion and thus can cope with higher speeds. A yacht will usually require a soft antifouling, which would erode too quickly at powerboat speeds - but (in theory) a soft antifouling on a yacht should erode at the same rate as a hard antifouling on a powerboat.
Stick a soft antifouling on a fast powerboat and it'll erode away very quickly.
Stick a hard antifouling on a slow yacht and it won't erode away much at all. To add insult to injury, the surface layer will eventually leach out all its algicides and without erosion, no new algicide will be able to get out - the result is slime/weed/barnacle growth. Racing yachts may use a hard antifouling, but will usually be lifted out during the season in order to scub off any slime build-up - and usually expose new algicide by scraping off the top, inactive, layers.
* there are probably exceptions...
On the plus side it is often the best colour on powerboats with a gelstripe as it doesn't clash.
But, white has a few downsides:
- Because the base, uncoloured antifouling is a brown sludge, a white antifouling will contain a lot more dye than other colours, hence it tends to be weaker. We tend to apply an extra coat of white compared to a darker colour
- Similarly, it is very difficult to get a very white sort of white: most whites are light grey
- Once launched, copper compounds (in particular) leach out and can stain the antifouling green
In terms of how an antifouling works, even a hard antifouling has to erode in order to work*: this exposes fresh algicide to give protection throughout the season. Thus, if you scrub an antifouling, flakes will fall off.
In general, a powerboat will require a 'hard' antifouling, which is more resistant to erosion and thus can cope with higher speeds. A yacht will usually require a soft antifouling, which would erode too quickly at powerboat speeds - but (in theory) a soft antifouling on a yacht should erode at the same rate as a hard antifouling on a powerboat.
Stick a soft antifouling on a fast powerboat and it'll erode away very quickly.
Stick a hard antifouling on a slow yacht and it won't erode away much at all. To add insult to injury, the surface layer will eventually leach out all its algicides and without erosion, no new algicide will be able to get out - the result is slime/weed/barnacle growth. Racing yachts may use a hard antifouling, but will usually be lifted out during the season in order to scub off any slime build-up - and usually expose new algicide by scraping off the top, inactive, layers.
* there are probably exceptions...
