A) The surface must be dry, clean, and free from grease or dust.
To be sure about this it is indispensable to sand and measure with an instrument, such as SKINDER or equivalent, in order to detect moisture.
B) Prepare the epoxy resin C-systems' 10 10 CFS and with a small brush "soak" all the biggest craters to fully impregnate the cloth. Then they are filled by adding mineral Microfibre additive to the resin. This filling will be stronger than the material taken away and will give to the hull the consistency and reliability as when new or even more so. When dry sand down to get a smooth surface again, and start the general phase.
B) Apply the first complete coat of C-systems' 10 10 CFS by brush or roller, up to around 6 to 8 centimetres above the water line.
C) After 2 or 3 hours apply the second coat of C-systems' 10 10 CFS.
D) After several hours, when the resin is still tacky like adhesive tape, fill the "craters" with NAUTILUS Epoxy Fast FINE Filler (fast drying) or C-systems' 10 10 CFS with mineral Microfibre or Thickener nos. 2.
E) The day after very lightly wet sand (grade 120 to 150) the fillings to perfectly level them and pass a wet sponge type 3 M Scotch Brite over the whole hull, using the rough part (to eliminate any formations of greasiness - blushing - and to guarantee a perfect adhesion).
F) Apply the third coat of C-systems' 10 10 CFS.
G) Apply the coat of NAUTILUS Epoxy LIGHT Filler with a toothed spatula to get the right thickness and make the hull uniform. When dry (between 12 and 24 hours or 1 to 2 hours for the fast types) after sanding dust off well and go over again with the smooth spatula to perfectly smooth the hull (see the more complete description under the heading filling).
H) Very lightly sand down to eliminate the small defects and apply a coat of C-Systems' 10 10 CFS; the following coats are applied with the additive A 20, until the resin quantity foreseen for the surface is all used up.
I) The antifouling can be applied directly, but it is preferred to paint the hull in a white colour similar to the gelcoat. 2 or 3 coats of NAUTILUS Epoxy Primer two are sufficient. It can also be applied (one coat is enough) to metal parts such as rudder, mountings, shafts, propellers, flaps etc. The first coat of NAUTILUS antifouling will be applied after 8 hours and within 30 days. The second antifouling coat will be applied only on the points where the keel blocks were, after we remove them from the hull, so that they remain for the moment outside of the treatment.
L) The second antifouling coat can be applied some days before launching. From the last coat of epoxy resin or NAUTILUS Epoxy Primer two at least 7 days go by before launching in order to be certain of cross-linking, in depth drying. When talking about the number of C-systems' 10 10 CFS coats to apply attention must be given to the resin thickness required for a good protection. The total quantity applied per square metre is of the utmost importance (600/700 microns), in other words to make 10 square metres of the hull 6 to 7 kg. of C-systems' 10 10 CFS are needed.
Applying thinner coats often means making a smoother surface, working better and obtaining a superior aesthetic result. The material described for the hull can also be applied to metal keels which, as we know, are important to be maintained free of corrosion. With the epoxy fillers, C-Epoxy LIGHT Filler and C-Epoxy FINE Filler we can bring them "to perfection", using more material where necessary to reduce water friction. Sandblast or sand down or disc sand the keel, to remove traces of any previous filling and painting taking it back as much as possible to blank metal and proceed as follows:
2 coats of NAUTILUS Epoxy Primer two (available in white and blue when it is necessary to see the topcoat)
2 coats of C-Systems' 10 10 CFS Filler with toothed spatula, and then the smooth spatula
2 or 3 coats of C-Systems' 10 10 CFS with A 20
2 coats of NAUTILUS Epoxy Primer two
2 coats of NAUTILUS Antifouling and.......happy sailing

Not all hulls have the same scattering of bubbles, just as their size varies and the depth of the fibreglass layers. If you find yourself in front of a hull where the osmosis spots are in the first stages and are of a size (once the "craters" are cleaned and opened out) not larger than a shirt button and with a "button radius" depth, the application of a suitable "ready to use" filler like our C-Epoxy fast FINE Filler, perfectly meets the requirement and we can be sure that over and above the anti-osmosis protection characteristic of our product, we have also an analogous structural resistance. Making the example that many of these "decays" have the size of a good "olive" or a "walnut", also if the depth is less than the "previous button", or, have even become the size of a mandarin, or even if they are small like in the first case but in some areas of the layer they are so close that "cleaning out" means them nearly touching, resulting in a much bigger "decay".
The question we can put is this: do we always have to fill and level with filler? It is simply better to accommodate and try to achieve higher targets. The use of C-systems' 10 10 CFS with mineral Microfibre additive (minute glass balls) in the measure of around 50% to70% in weight, forms a pasty, fibrous, dense resin to stay-put even on vertical surfaces, reinforced, multi-directional. More than just filling the cavities, it becomes an active interacting part with the layer and in many cases with a better form than the material taken away. If the there are a lot of much bigger spots with a noticeable delamination, it may also be necessary to reapply glass cloth in order to not to compromise hull quality, but this possibility must be evaluated case by case.
The technical "mix" made with C-systems' 10 10 CFS and mineral Microfibre is less easy to spread than filler; due to the fibres intertwined with each other that pull other fibres when put on the spatula and spread. It is recommended to apply a more abundant quantity of material to avoid possible empty spots and, when dry, with a sanding pad and paper, grade 60 to 80, sand down to give the right profile to the repair.
Now the hull of our boat has again all its mechanical integrity and will be "started-levelled" by the work made by us in order to eliminate the parts compromising the layering. It is important to note that as it is better to apply 3 thin coats rather than 2 almost sagging coats. Apply C-systems' 10 10 CFS with a roller, it is extremely easy, fast, clean and not tiring. Not having sags saves the time need to sand down the dried drops. Two or three coats of NAUTILUS Epoxy Primer two before the antifouling is the right answer to have a perfectly uniform colour similar to the gelcoat, and also using the self-polishing antifouling, like Nautilus S.P., will not touch the transparency of the epoxy resin. NAUTILUS Epoxy Primer two doesn't only have gripping characteristics on the previous coats but forms a structural union and has a notably higher resistance over traditional grip characteristics. The first antifouling coat follows between 8 hours and 30 days later. The second antifouling coat will be applied at least 48 hours before the launch. Time for the launch at least 7 to 8 days after the last coat of NAUTILUS Epoxy Primer two or C-systems' 10 10 CFS.

Today, more than 80% of boats are in GRP or as normally called "plastic", but this marvellous product has proved to also have some defects, among them permeability, that is water absorption which, although less than wood, is bringing in the great number of cases, obvious negative results: osmosis. The use of C-systems' epoxy range (structural epoxy system) among which C-systems' 10 10 CFS with the relevant additives and fillers, brilliantly resolves and prevents this problem and in a definitive manner. Osmosis is a phenomena of diffusion between two mixable liquids of different density that penetrate through a semi-permeable membrane (the semi-permeable membrane in this case is actually the gelcoat and the laminate of our boat). The most dense liquid is to be found in the layers of our boat as the result of bad workmanship or catalysis, or is created by hydrolysis with the passage of water through the gelcoat; the most fluid being the sea or the lake that our boat sails in, and that passes through the gelcoat causing all the damage which we know well. Osmosis manifests itself above all in the hull because it is the part under water, in continuous contact with the water absorbing a quantity that goes to dissolve unstable and water soluble residues (hydrolysis - separation of a substance due to water) originated during work and forms very dense liquid substances. In some cases, particles of dense liquid are already to be found in the layers due to the construction.
The factors causing the internal malformation of the fibreglass layers during the initial work are many, among them not having the right temperature, working humidity, trapped air bubbles, the low standard of materials used, the lack of homogeneity between them and the storage of the raw materials. Nevertheless, these negative factors need water to develop the undesirable effects we know. Through gelcoat micro-porosity, cracks, dents or something else, the sea water, being more fluid than the liquid found in the layers tends to penetrate, and where there are these small dense concentrations diluting them down to the same density; this causes an increase of liquid within the layers (liquids are not compressible), and therefore an increase in volume that manifests itself as a small protuberance above the smoothness of the hull.
Osmosis manifests itself more easily in fresh water (because it is more fluid than sea water, not containing salt) and in warm water because it has more fluidity, therefore a mooring near a warm water discharge will show up the problem sooner. At first sight it looks like small swellings, like hardly projecting grains of rice, similar to a light orange peel. With the passage of time they get more robust, increasing in volume (because the internal pressure increases) and in number (the imperceptible ones begin to acquire volume) weakening the layers. The moisture access ways, beyond an imperfect gelcoat impermeability, are also the stress and dents that the hull suffers (for example when taken out of the water and poorly propped), the sea valves and the discharges under the water line, that in many cases are protected only by a line of silicon and not fully sealed. Besides, once water has entered, the continuous movement and the strain on the boat when sailing or moored, make these microscopic drops of water mobile.

It is recommended to take the boat out of water and to shelter it from any showers and from dew. Keeping it in a well equipped shed is the right condition, but experience tells us that more than half of the interventions are made in not ideal conditions, where the good intentions of the owner or the worker compensate for a certain deficiency without compromising the final result.
Carefully clean the bilge, vigorously wash with Boat Life BILGE CLEANER (this operation is best started some weeks before "at sea", in order that the BILGE CLEANER detergent works well and long) and dry out perfectly (to avoid that any internal cracks bring the moisture that we are trying to combat). Proceed to the complete removal of the antifouling and the hull gelcoat, taking care in suspect areas to be more vigorous. This can be made in various ways that go from sandblasting, (therefore by a specialist), to disk sanding or belt sanding, where the sanding belt has a very efficient rolling action. The paper is to be 40 grain, but for this type of work, the treated surface has a greater smoothness than the paper number says. In some cases, as you can also see in our VHS video or CD dedicated to C-systems' 10 10 CFS (available from our sales outlets or directly from us) using a simple electric plane with the blade adjusted very low the gelcoat can be removed in one go cleaning the hull very well and opening the protruding bubbles in the right way. To do a boat of around 11 m at the water line you need two sets of blades that are sharpened 2 or 3 times. With a little dextrousness and patience a very good result is obtained in a much reduced time.
Sandblasting, when available, remains the most efficient operation and in just one go takes away the antifouling, the gelcoat and the bubbles, that by now have a soft layer and are opened up in a moment back to sound material. It reduces immediately the moisture content leaving the surface porous that dries out better. In fact, also using the other tools, a light sandblasting is needed (water jet sandblaster, more easily obtainable) to open the pores. It is important that the work is started a short time after taking the boat out of the water.

The bubbles, the osmosis swellings, are opened to also free any water retained inside and cleaned (we've called it water but it is actually a more or less acid liquid depending on the concentration), open them far enough up in order to be sure that all the "rotten" part is completely removed finding perfectly consistent lamination again at the edges of the "craters". Give a good wash, if possible with hot water under pressure, to take away all the osmosis residue impurities and the dust from the work made. Washing is extremely important in this early stage, several times during the drying out and at the end. The liquid that formed inside the layers is dissolved only with water (much better if hot) and then all the energy of the pressure and insistence with which we work ensure dissolving also those crystallizations which may have formed. It is important to note that aggressive or mild solvents have no effect for the cleaning. If a hot water pressure cleaner is not available, then a bucket, a sponge, and a hose work as well, even if it takes much more time.

It is of fundamental importance that before treatment the hull is perfectly dry; the reference, with SKINDER, can be made with the measurement of the hull above the water line; the value must be the same as that in the underwater hull. One or two days before applying the resin (according to the season) it is indispensable to wash the hull again with fresh water, as we did after removing the gelcoat and many times, periodically, during the drying out. During the drying out, whether naturally or induced, distilled water evaporates, because the salts and the acids remain on the surface. It is necessary to periodically remove them by washing several times during drying out, because these residues can be taken away, dissolved only with water. The wash down before treatment dries very quickly and as the check with SKINDER impartially shows, returns to the previous values in a few hours.

When moisture manages to get into the fibreglass, this happens through gelcoat porosity, and through the dents and stress the hull has suffered. In the parts out of water, it has difficulty to develop, because for the times of absorption (for example think of a boat sailing close-hauled or under sea spray) there is an extremely longer corresponding "drying out" time.
When moisture or water penetrates, it has to find favourable conditions in order to cause osmosis, otherwise the boat is weighed down by a certain percentage of moisture (like marine timber) proportionally losing a part of the resistance to fatigue and all remains there. Osmosis manifests itself when water finds favourable conditions or water soluble substances. To avoid this inconvenience, today, many builders have taken the right countermeasures, nevertheless in case of doubt, and for greater security it is advisable after removing the wax and the separators, to give the hull a fine wet sanding and apply 3 full coats of C-systems' 10 10 CFS followed by the first coat of antifouling 12 hours later.
This treatment is a good investment and a good saving, also considering that the major part of the antifouling requires an undercoat for GRP. C-systems' 10 10 CFS is available also in the version white. It is slightly thixotropic to hold better on vertical surfaces, has the gelcoat colour when you make the preventive work on a sound or new boat and has the same mix ratio, same pumps and same additives. It is available in 1.5, 4.5 and 30 kilo packs.

To our sellers or directly to us it's available a videotape VHS of about 55 minutes duration with instructions for use about epoxy resins and with a space devoted to osmosis, preparing of the surface, applying of C-systems 10 10 cfs covering with filler and antifouling. The videotape is extremely interesting thanks to the various workings and solvable problems in the easier way. With a particular refer to the planking boats it's also available a completely working with epoxy resin for caulking, replanking of the hull and many examples of building, repair, modification, covering with filler and painting. The duration of this videotape is about 90 minutes. Also this it's available to our sellers or directly to us.

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