Satin weave is also another alternative… Still frays very badly along the cut edges though!..
Hi Jim
Boom heiht will remain the same, only wanted to acheive better angle, or in fact im just moving the attack point towards the end of the boom. I hope this couldt give some advance in form of better controll of the main, and less tension in the vang, causing also less mast bend in the bottom section… but honestly I have no idea if there is something to gain.
Some times I jus like to do things a little different, if i feel it could work better or just as well, if we all do everything the same way, we would have no evolution…
Regarding the fraying, would it help to mark the outline of the piece of fabric with masking tape before cutting in the middle of the tape, and leave the tape untill the fibres are wetted out in the mould, then cut it before applying the peelply and the rest of the vaccum gear? Or would this tape also restrict the draping as the fibres a locked in the ends.
Fom the experience with the carbon test i bellive i would be able to pull off a twill laminate. My strongest weapon is my patiece… my mom always says I have the patience of an angel 
Will have to keep the kitchen budget at a minimum, so i can affort vacuum gear…
/Anders
Correct.
Especially on the 45 bias.
Whilst this is a useful technique, for this application, you would be making the job much harder for yourself.
Hi Anders, found break in the day to start little prep for Latex method which I’m trying for the first time on my AC 100 project.
Problem I saw in the few photo’s I’ve seen of others trying this process is that didn’t prepare to make things easier, first problem I think needs to be done is to elevate the mold from work surface to give some space to work around the male mould.
The concept is to stretch the latex over wetted laminations on the mould and hold the stretched latex by stapling it to the building board, here I plan to simply use strip of 3 x 5 mm balsa strip, stapled along the length of the base of the building board.
To avoid wrinkles & folds in the Latex, I have cut my building board to approx 2-3 mm narrower than the sheer line around mould, then screwed the building board to 50 x 100 mm block which I can clamp into mobile vice work bench so I can work around the mould stapling down the Latex onto side of the base board …well thats the theory 
As precaution I’ve drilled few holes into the building board & some of the frames & locked the mould into position with plastic tie-downs, just to avoid any possible slippages. Also need to mask the gap between mould & the base board so epoxy does not run in unwanted places :scared:
Have picked up different thickness of Latex to “dry run” to check how staples & Latex will hold & if there are any other problems, I will dry test the Latex when I’m back next weekend.
Cheers Alan
Hi Alan -
you may enjoy some of the email and advertising “offers” you get if you searched/purchased on-line. Suffice to say the offers are aimed at -ahem - “adult activities” - and NOT of the r/c sailing type. :rolleyes: :eek::lol: 
Wax paper and 3M77 to the rescue, to stop fraying.
That is, take some wax paper and lightly mist it with 3M77 spray adhesive. Then lay it down on your cloth, smoothing it out, flip it over so the wax paper is on the bottom. Use a roller cutter to cut the carbon fiber cloth or fiber glass, shears for Amrid/Kevlar. Right before you are going to lay up the material, peal back the wax paper a bit (no gloves). Chose a direction that will minimize the odd thread from being peeled out of the cloth when you pull the wax paper.
Wet out your surface, now you have a choice, peel off the wax paper before laying down the cloth, or lay down the cloth then peel off the wax paper.
No more frayed edges
Hi
So Alan’s question about the Clearance between vang and deck, got me thinking. I am beginning to think if I am creating allot of trouble for nothing, so I decided to put some science (Not rocket science:)) in to the matter, to see what the difference would be.
I made an Excel spreadsheet to calculate the different forces resulting from a given force applied to the mainsail. Attached is a screenshot of the spread sheet, could not attach a .xls file. 
Here is the sketch of the system:
I set the applied force F2 to 1N just to get some reference numbers. I set my boom length F2=356mm
I then created 3 different scenarions, see bellow. The red one is meant as a reference to a normal deck height vang.
Results:
Red
Inputs: A=63mm b=75deg B=234,5mm
Results: F1=6,01N Fboom=5,81N Fvang=-5,81N Moment from force couple(Fboom/Fvang)=0,37Nm
Green
Inputs: A84mm b=67deg B=197,6mm
Results: F1=4,73N Fboom=4,35N Fvang=-4,35N Moment=0,37Nm
Blue
Inputs: A=93mm b=57deg B=143mm
Results: F1=4,68N Fboom=3,93N Fvang=-3,93N Moment=0,37Nm
Conclusion:
Well… it will reduce the forces in the vang by arround 24% if comparing red and blue. I also reduses the forces on the boom and vang hinges, but the bending of the mast is the same.
So now the question, is it worth all the trouble of making a special and more complex finn trunk and mast support structure under deck? What do you guys think? In one way a gain of 25% is not bad, and maybe that is what is needed to get perfect control of a mainsail with a big head. Does anybody have an idea if a more powerfull vang would even be an advantage with a big head main?
I think this is all for now, the kitchen plans is postponed one week, so I will be using the extra time for finishing the boat plans. Will return soon with a foredeck layout…
/Anders
Anders - only as a point of reference and experience - on pretty much all of the current beach cats, they use a boom that terminates to the mast, or to the deck bean just to the rear of the mast. The boom uses boom end sheeting and often an 8:1 ratio. This boom end sheeting, in conjunction with a total boat width traveller (anywhere from 3meters to 4 meters in length) handles all the angle of attack, sheeting and leech control for the “fat head main”. Seldom do they use a vang - but that is because the traveller can be sheeted out to one side, and the mainsheet/boom sheeted in, thereby controlling leech tension (and twist). I would suggest that if the monohull were as wide and used a traveller - it would also work without a vang.
Only an opinion of course. Note that catamaran masts are stepped on the front cross beam and usually on top of a ball that allows mast rotation as well.
Cheers, Dick
ADDED: Here is alink with some info written by a well known US Sailmaker. While it doesn’t address your interes in vangs, it does provide a bit of information on the big top mainsials. Enjoy: http://www.sailinganarchy.com/article.php?get=1134
Hi Dick
Thanks for the link, there is allot of good information inthere. He does mention that fat-head sails needs harder sheeting. If we shouldn’t burn the whinch, this tension would have to come from the vang, and could justify the more complex setup under deck.
I have another little issue. As I plan to have swept back spreaders and shrouds the main boom will not be able to go out to 90 deg. Is there a roule of thumb as to what the main an head boom angle should be both up and down wind? This could help to determine the angles of the spreaders, and also the final angle of the vang…
/Anders
Hi Anders,
So the kitchen project on hold buddy! …how did you manage that ? I’m always looking for new excuse for my boss to escape back into my more important things in life …like my sailing projects
Don’t know if you read the post on rig sail fine tuning but I posted my thoughts which maybe worthy to look over http://www.rcsailing.net/forum1/showthread.php?5984-Rig-Sail-Fine-Tuning/page4 but don’t take it as gospel, as I’m still learning the finer aspects of RC sailing too.
You touched on three points, large head main sail, the vang angle and the mast bend, I too got stuck in thinking about too many variables and at the end of the day started confusing myself, finally had to accept that I needed to experince things to learn and don’t go looking for problems, they will eventually find you anyway 
I picked up earlier in one of your posts that you were going to order a mast from TD model, I have two of his stiff foil shaped carbon masts which are also tapered, I have the absolute minimum of mast bend due to their profile & construction, so the only benefit you will have from having swept back spreaders, is that you will be able to transfer more tension into the Jib front stay, which is always a good thing…how much? I would consider if you can have your main boom swing maximum of 85 degree’s off the centre line. Running at 90 degree’s, I’m not sure it would have any really any extra speed avantage, other may have more experience ?
Have attached pic with birds eye view of spreader angle on my boat built by TD model, which has round carbon mast that has quite a bit of bend in it, just to give you an idea, the stiff mast has less than half of this bend in it.
In regard to your vang, it’s function is to control twist of the main sail, just be sure to position it at least 30-35% of the boom length from the mast, to have enough leverage to have max main twist control when you want it … it also needs a strong enough attachment to the goose neck or mast, I have seen a few vangs break, pop off or jam with too short vang points having high tension against the mast connection … me included :scared:
Our boats need vangs because we are limited to having only two servo’s and with one controlloing both main and Jib you need to ensure the sheeting length are the same for the Main and Jib otherwise boom angles will change during their sheeting lengths…not a good thing.
With a big head main, there is a lot of roach you want to control, Jim’s tapered battens idea will definitely help hold up the top of the main leech together with right camber built into the mainsail and the mid to lower part of the main is mainly controlled by the vang again…need to experince it to really learn about it.
Back to the mast, there is reasonable amount compression taking place at the foot of the mast, ensure you have good support in this area around the mast step (deck or keel).
Cheers Alan
Just outside of my window !
If this may help ! the tecnique and proportions are of interest !
ClaudioD
Hi Folks
As it has become a bit of a must, to have lego man supervising our boat builds, I put out an add in the local Lego news paper, that I was looking for a qualified boat builder and supervisor.
Yesterday was the day for interviews. And as you can see the queue of applicants was long.
I had my 5-year old nephew help me pick out the most qualified. And we ended up with two very qualified workers. The first is Bob “The boat builder” and the other is… welll… you might know him infact… Some says his saliva was used instead of epoxy for the BMW Oracle tri… others says his tears can cure cancer (Too bad he never cries)… All we know is… Hi’s called THE STIG!
Things are comming together now. I have got the key for the garage/ship yard and I will start installing the new kitchen today, and expect to finish 13th of march. After that, all focus will be on boat buliding…
Over and out…
That is excellent Anders! I especially like your stig! I wonder if he’s fast at the helm of a sailboat too…
Hi Anders,
Had few spare hours today & decided try my first trial lamination using Latex:
Used 245 gsm Carbon twill which draped beautifully over male mould, trimmed allowing approx 30 mm all round over-lap, masked taped around the based and then laid carbon over the hull and flooded it with epoxy careful to ensure no air bubbles.
Next stapled one side of latex to the base board and then stretched it over the wet lamination and stapled the other side to the base board, here you need extra pair of hands, one stretching the latex while the other staples strip of 3 x 5 mm basla or similar.
Worked perfectly & very clean, have very few small air bubbles and will try Bascofiller that Jim spotted @ P&G, was in there today, really nice & helpful people.
Under 24 hr cure & looks promising, will see tomorrow
Cheers Alan
FIGJAM :spin: it works perfectly! …few minor pin holes but otherwise wunderbar !!
No more sanding or painting, huge weight saving, hull weighs in @ 145 gsm
Cheers Alan :zbeer:
is this ac100a? hi alan, see you in rome on saturday?
Hi Alan
Looks very good. Just beautifull.
By the way, the kitchen is as good as done, only missing some minor paint jobs, which should be taken care of this weekend. Also this weekend I will try to install a working table/bench in my garage so i can get the building going. Hope to order GF, CF and epoxy from R&G this week. Even though the latex method looks very good, I have found room in the budget to purchase a vacuum pump, so will be making my hulls with vacuum. It will also come in handy for some other things I have in mind, regarding construction of the inside parts. But thanks for sharing you experience.
Hope to be back soon with some actual boat building progress…
/Anders
Hi
I was just about to order fibre an epoxy, but then i came to think about mould release… Is there special requirements to the release agent when working with vacuum? Can anyone advice me on a good product? Preferably from R&G .
Regards Anders
Hi Anders,
There is no real change in the requirements for a release agent depending on if Vacuum is used or not.
I would however recommend using a Hi Temp variety wax as this then covers you if you wish to post cure the components.
You can also heat the components whilst curing to reduce the resin/fibre content further.
We only use the Hi Temp Wax variety in the boat shed… and with the correct application, never gives any trouble.
Cheap small moulds can be made by using this wax with brown parcel tape.
Make your mould and prep the surface by sticking brown parcel tape over the areas to be laminated , try and butt join the tape as this gives a better finish later. Then prep the tape with 5-6 coats of wax, and you are good to go!
I have used PVA in the past (more than 10 years ago) but it is for an extra insurance that the part will release and is not widely used anymore with epoxies.
Instead we use Teflon tooling tape “Tooltech” which has replaced the need for this insurance on big parts.
Good luck,
Jim
Hi Jim
Thanks for the input. Just ordered 825 euro worth of materials and equipment from R-G… :scared: :scared:
:scared: :scared: :scared: :scared: :scared: :scared: :scared: :scared:
Really looking forward to get going…
/Anders