Anti-fouling --- which one?

Not strictly a CC19 question but more of a general query. I now have a GRP Lune Whammel trailer-sailer which has, I think been anti-fouled from new, about 8 or so years ago. There are a few areas that have been touched in over the years, presumably to cover scrapes etc. The paint is of a type that doesn't rub off when you touch it, as did the awful stuff that was on Falcon. Are there any recommendations from the team as to what I might use to paint over the existing finish to make her look as tidy below the waterline as she does above?
Spending all her spare time on a trailer doesn't really justify the expense of anti-fouling, but as summink has already been smeared on I suppose I'm stuck with it now.
Steve

Spending all her spare time on a trailer doesn't really justify the expense of anti-fouling, but as summink has already been smeared on I suppose I'm stuck with it now.
Steve