Sharpened for winning... Take a look under the hull of a racing Figaro 2 or Surprise: it's incredibly smooth, right? Nothing to do with the unfortunate surface finish of a production boat delivered by the shipyard. On the smooth gelcoat of a cruising yacht, the antifouling is applied with a roller. In addition to this necessarily very granular application, the keel's cast iron is roughly coated, the keel/hull connection is not masked, the through-hulls are not fairing. In short, all that is missing is a fixed propeller to definitively undermine the boat's potential. Let's face it: the hulls of good racing yachts are prepared with great care to improve glide. That's the basis.
It is then necessary to preserve this beautiful surface. Two schools of thought: no antifouling and storage on land - this is the formula used for small one-designs and teams with large resources - or application of a hard matrix antifouling paint (preferably Teflon or copper/carbon) and regular diving to clean the hull.
Another interesting alternative is the process of copper embedded in resin (M300 or Copper Coat). It is a mixture of resin and copper, a real film with optimum glide. Guaranteed for five years, these products are attractive, but must be applied with care.
Once the boat is out of the water and well secured, the Kärcher goes into action. Be careful not to damage the surface: the goal is to clean dirt and shells, not to attack the gelcoat! If the weather is cool, put on a good old-fashioned oilcloth.
The keel/ballast connection is traditionally subject to delamination of the plaster. This is normal: the filler is often thick and the stresses are high. Each crack results in a small water ingress. The cast iron rusts and bursts the keel joint. The damaged area is sanded with an orbital sander.
The leading edge is obviously exposed to heeling. As for the trailing edge, it must be perfectly symmetrical. Do not hesitate to use templates to ensure this. But beware: some one-design gauges limit the quality of preparation. Ask for more information.
To smooth out the rough edges, putty is used. The more careful use epoxy. But the long drying times and the requirements in terms of temperature and hydrometry motivate some racers to use polyester putty.
The propeller is obviously foldable or steerable. Fixed, it makes the boat lose 0.2 to 0.5 knots and above all limits considerably the accelerations. The blades, the shaft and the chair are stripped with a discer. The blades, shaft and chair are exposed with a grinder, finished with 400-grit paper and a metal primer. Remember to mask the location of the anode to keep a good electrical contact.
One of the secrets of gliding: limit the number of through-hulls by favoring, as here, speedo/sounder combinations and integrate them into the flange by dishing out the hull. Remember to remove the probes or mask them before applying the paint.
Tough debate! Is it better to improve the glide even more and do without the strainer, at the risk of swallowing plastic bags and algae through the sea water inlet? The skippers of our Grand Surprise could also have fitted a flatter strainer.
Before applying the paint, the vivid works are protected by a plastic film or newspaper. Beware of the wind: don't risk "painting" the sailboat next door when you use the spray gun!
The most exposed areas (keel and keel joint) are more protected than the rest of the hull: they are entitled to an additional coat of primer. The application is best done with a spray gun for a smoother finish.
Let's go for the spray painting. Apply in criss-cross strokes, then finish in the direction of travel of the boat. Do not paint the propeller or the anode location on the shaft.
After a good night, the antifouling is dry. The "fog" is removed with very fine water paper (800 to 1200). The hull is regularly wetted with a sponge and then immediately sanded. This is a quicker job - two to three hours - and less tedious than it seems.
euros negotiate with the crane operator before launching: we take advantage of the fact that the boat is suspended by the straps to prepare the surface and apply a coat of antifouling to the places previously masked by the ber.
All that's left to do is to put a 1,000-euro sandpaper under the water.
