Planked boats

For this type of boat, the most traditional construction, filling and caulking have to be carried out periodically.
The C-Systems’ 10 10 CFS epoxy resin, if used properly, reduces this maintenance repetition and “extends” sailing.
We want to solve the problems related to gaps in solid wood planking, including the joints at the stem, stern and the relative screws and nails which fix the planking to the framework.
Let’s see why the timber shrank and the courses which were put in place by craftsmen and “kissed” so well, are now open. Moisture penetrates through the paint film, which might be very compact but still has micro-pores, through which there is a continuous absorption and release due to temperature variations. The penetrating moisture saturated the wood grain dissolving microscopic amounts of natural sugars, starch and lignin, which form the structure of wood. This continuous flow removes from the wood, together with other important substances, also part of its volume and the board tends to shrink and show its seam.
The same can be said about originally caulked boats, as caulking has to be remade after some years and it has to be ever thicker in order to fill the larger gap created between the planks. What’s described above is very brief, but it describes the wood’s behaviour because we must be convinced and sure about the work we do.
For the underwater hull and the remaining planking (topsides, deckhouse, etc.) you proceed in the following way:
A) Burning off or disk sanding, in order to strip the wood right down or to leave it with only very few traces of old paint.
B) “Open” the seams between the planking courses and the plank ends , including those on the stem and on the stern and transom.
C) Insert 40 to 80 grade glass-paper folded in two between the planking to clean them thoroughly.
D) If necessary “strengthen” where the boards don’t “sound” properly, with screws; if possible put some drops of C-Systems’ 10 10 CFS in between the parts which are going to “touch” so that the board has a larger contact surface.
E) Apply a thick coat of C-Systems’ 10 10 CFS on the seam, insert the caulking cotton (or hemp) into the seam and carry out a good caulking, doubling or tripling in the largest points the wadding thickness or reducing it (by breaking it) in the narrowest points. Work in such way that the caulking remains some millimetres below the board surface.
Over the caulking apply two or three coats of C-Systems’ 10 10 CFS making sure that the caulking cotton is soaked and completely impregnated with resin.
The caulking cotton is a cotton “twine/string” available in different diameters. We supply 3 and 6 mm because in the case a higher diameter is needed its possible to double or triple it to make it suitable to use. In comparison to oakum caulking it does not contain any heavy oil or bitumen. It is put into the seam still fresh with C-Systems’ 10 10 CFS resin, brush C-Systems’ 10 10 CFS several times onto the caulking made, and the caulking cotton as it absorbs a large quantity of resin increases its volume. In this way it closes all access ways to the caulking creating a very good and long lasting joint between the boards. Be sure that the caulking cotton is “trapped” at least a couple of millimetres under the board surface e then covered again with structural filler made with C-Systems’ 10 10 CFS added to natural micro-fibres. The following day, on sanding the treated surface, we will admire a perfectly continuous board structure and a new integrity of the planking.
It is important that the resin completely soaks the caulking cotton because the latter is going to increase in volume, so closing the gaps even more, remaining perfectly and integrally attached to the board forming an exceptional joint. Instead of using caulking cotton you can take up the play between the planking by using strips of wood after having thoroughly cleaned the seams.
Prepare some strips with slightly truncated conical shape which we want to insert in the spaces between the planking boards, without being too worried whether we will need more than one piece to cover each seam its full length.
Apply C-Systems’ 10 10 CFS into the seam and onto the strip which will be used to close the seam.
In the seam again put some C-Systems’ 10 10 CFS mixed with natural micro- fibres (until it is as thick as a jam) and insert the prepared wooden strip pushing it lightly in the opening so that it mates the boards together with the filler made with natural micro-fibres. Proceed this way for all seams. Regarding the rounded parts (stem, etc.) these areas are made using caulking cotton (oakum contains tar and cannot absorb paints or resins) and then you carry on as indicated for the caulking.
Once the caulking and strip insertion are finished you will be able to appreciate the perfect structural sturdiness given back to the boat, and we go on with the work
F) Perfectly sand and polish the entire surface.
G) You have to prepare a certain quantity of C-Systems’ 10 10 CFS (A + B) resin by using batching pumps (your work will be faster and safer) and alternatively pumping in this manner; pumping A then B, then pumping A and then B again and so on; in this way the resin and the respective catalyst is distributed more uniformly (Note in 1,5 kg packs micro pumps have to pump twice A and then once B and so on in order to maintain the correct C-Systems’ 10 10 CFS mixing ratio).
Mix well and pour the resin into the plastic bowl to increase the mixture’s life and to work better with the roller or with the brush.
“Soak” all screw and nail heads with the resin.
Apply the resin on the hull and work for about 20 minutes, than start from the beginning again taking care to go over again the areas where the wood strongly absorbed the mixture and needs more again.
Go on from where you stopped and proceed like before, redoing from time to time when you see that the surface is becoming matt. Repeat the operation several times in order to deeply impregnate the wood fibre and make sure that the latter absorbs up to saturation point (up to four or five times depending on the wood quality and condition).
Let it dry for one day and you will notice how everything is perfectly consolidated. The wood, even where it was stressed, absorbed a certain amount of C-Systems’ 10 10 CFS transported along the finest fibres thanks to its low viscosity and bonding in an excellent way, saturating and strengthening the entire structure, in this way we continue the work.
H) Wet sand lightly, or after having sponged the entire surface to flatten down the wood fibres, then apply a second coat (A+B) of C-Systems’ 10 10 CFS. Epoxy resins have always to be wet sanded, or after sponging down the surface (like when washing our car windscreen).
I) Apply onto the remaining imperfections, heads, etc., a coat of filler made up of C-Systems’ 10 10 CFS and Microfiller Powder, or natural micro-fibres or thickening agent nos. 2 .
L) Sand and level off. Apply C-Epoxy LIGHT Filler on large imperfections.
In order to properly smooth and level the entire surface, apply a C-Epoxy LIGHT Filler coat with a toothed spatula to obtain an uniform layer. The following day, or when it is just dry, sand with 40 grain paper over a wooden sanding block and apply, after cleaning and dusting the surface off well, another C-Epoxy LIGHT Filler coat with a smooth spatula which fills and levels completely the previous layer.
A hull surface prepared and rubbed down this way will give higher speeds and achieve a high level aesthetic finish in the topsides.
M) Apply another 2 or 3 full coats of C-Systems’ 10 10 CFS on the hull followed by 2 coats of anti-fouling and… good sailing.
It is advisable to add A 20 to these final coats.
N) Protect the sides and the deckhouse with at least two coats of NAUTILUS Polyurethane Enamel.
It is advisable to apply at least one or two primer coats before anti-fouling NAUTILUS Epoxy Primer due (white or blue colour) because it is not only characterised by adhering to epoxy, it also creates a solid union with the latter and has much higher resistance than classical coatings. Furthermore a self-smoothing anti-fouling like Nautilus S.P. doesn’t show resin transparency. For the sides and the cabin it is indispensable to apply NAUTILUS Epoxy Primer due otherwise the paint will have problems to cover the work made. From the last C-Systems’ 10 10 CFS, NAUTILUS Epoxy Primer due or NAUTILUS Polyurethane Enamel (white or blue two-component enamel) application wait at least for 7 days before putting the boat into water for the first time.