here I would like to present my attempt on building a national class boat, which is a variation of RG 65 boat. At the moment I am at the stage of awaiting resin to cure, and over the weekend I will be pulling the hull out of the mold. In the meantime I will post some pics how I made plug, mold etc. Right away comes my first question. Would someone recommend for me some plans for good performance sails for light to medium winds?
these up here show my way to the plug (this is what you call it in eglish i guess)
these is my one piece mold and what came out of it
now I have a two piece mold, I waxed it pretty good and the hull will come out smoothly!!!
to be completely honest I have no idea what is a “one design” RG 65. The boat I am building is of my concept and design, according to our national nss 650 rules (if you want to take a look at them, i published them on my introduction). I am obligated to go for the sloop sails (class requirement, no rotary masts or sail-o-masts). Thanks for the lead on the sails.
as I say, this is the variation of RG 65 class. about the sails, I consider wider and lower sails vs narrower and higher. We mostly have light to medium winds, so the balast I use is not to exceed 350g so i tend for the lower sails to start with. The heel is not going to be too big.
if 350 will not do then I will replace it. I know a guy who races with balast up to 320. Tall and skinny look very good so you are right it’s better to play around this season I won’t start in anything so I have more than plenty of time
today I pulled the hull out of the mold :))) it looks pretty good, there is only minor holes to be filled. I am also glad about the weight. The raw hull as seen on the picture is only 108 g. So far so good. I let it sit some more in the mold for seasoning and in the meantime I will work on keel rudder and balast bulb
watching your last image, I got the impression that the Fin thickness may sit around 26-27% and the Rudder around 20-22%.
This value is rather unusual since for better performances, the fin should stay between 7% and 9% and the rudder usually between 10% and 12%.
Of course I understand that wooden appendices cannot offer sufficient strength is the thickness is reduced.
I have tried with Australia to do cast a mold with keel and bulb, although I didn’t try to pour lead into it (the bulb I made with Claudio’s technique from 122 thread). I won’t do it again this way because it is too much of the effort in compare to results. The bonds of the two halfes of the mold still need to sanded and played with so it doesn’t really pay of.
going for the full sail area, a 350g bulb will only work in very light winds. With my RGs I have never gone below 450g (standard is 550g) on a 30cm fin. The trend is to build more lightweight and to increase the bulb’s weight to about 650g (or even more)
The hull seems to be rather heavy with more than 100g without deck. This can be done with about 65g without problems, using 2 layers of 80g glass fabric and 1 layer of 49g, for example. I have build hulls down to about 50g using one layer of 93g carbon and one layer of 49g glass.
Pinholes will always be a problem with such thin and lightweight laminates. I achieved the best results when applying a rather thick laver of thickened epoxyresin into the mould. Then put the first layer of glass or carbon in (without wrinkles!). Let it soak with resin from below by itself, which takes about a quarter of an hour or so. By this you avoid air bubbles in the fabric. Only then you can roll it down and squeeze it a bit. After that you can apply new resin (if neccessary) and the remaing layer of glass or carbon.
thank you for the advice. the thicker resin to start with makes sense to me now that you gave me the idea, I will apply it on my next boat the bulb I will make heavier around 480 g now that everybody is pointing it out. on the other hand, how do you deal with the pinholes that you already have?
To fill the pinholes I paint a section about as big as my hand, rub it in with my fingers and then wipe it off with a rag. You will see the paint come through the pinholes. This will fill the holes that go through the hull. I’m not sure how well it fills the holes that don’t go through.