'Anti-foul Language' - so to speak!

Anti-fouling paints depend on biocides in their make-up to inhibit growth of weed and barnacles and are usually hard or self-effacing. In the case of anti-fouling aluminium hulls it is important that the biocidal component, once tin and now copper, doesn't act electrolytically.
    As best I know some copper containing anti-fouling can be use on aluminium but breaks in the undercoats, if untreated, can initiate focal electrolysis.

Another slant at preventing or inhibiting growth on the hull is manipulating the surface such that adherence is impossible, difficult or tenuous when and where motion of the boat through the water is enough to swish or brush growth away. An exciting product, if it works that is, decreasing toxic material in the worlds oceans. Of course one has to think ahead and take count of processes in its manufacture and eventual degradation.

Hempel paints have made a new product called SilicOne for that very purpose, being a three component item, the application of which needs to be somewhat disciplined. It is this I have used on Tuanella 3. The items, a epoxy-resin base, a tie coat (ocre) and the business coat (coloured - in my case, red) come in relatively small size cans (750ml) to avoid waste because the pot life is short (an hour). Understandably the applications need to be quite close together  to allow next coat adherence before drying, and as much as possible each coat covering the entire surface in one. Not always easy this because of the hull supports, so the margins of those areas have a paint free cuffs of each coat that are picked up when the supports are shifted.
Hempel state that the boat should be launched within a month of application of the final coat for best results.

Brush or roller, that is the question. Doing both I found the roller best, as the moment from the axis of the roller surface to its handle is considerably greater than that from the brush drawing action from surface to wrist in the case of a brush and the axle of the roller is relatively friction free. Also the volume of paint 'held' per dip is greater.

I  found with the narrow short haired roller (1") I used held the roller tight on the surface. Patently for nooks, crannies and welds a smallish (1") touch up brush is indispensable.

The finished surface is shiny, rubbery and clammy to the touch, I suspect altogether quite uninviting for the barnacle larvae to attach and how they do so on whales is remarkable.
Paradoxically the surface feels and acts anti-slip as the picture indicates.

As best I recall there are two colours to chose from and I chose red over black, being in my mind the easiest to see if the boat is turns turtle. The picture below shows the colour well.