So… another day with no wind…
What are you gonna do?..
Make some more advancements… and start to push further on…
Still not much wind, but went sailing regardless.
Sailed perfect!
Compliments! Sails seems to work well. She is a little bit “high” on the water especially the bow: is she without ballast on the hull?
Hi, she should be more or less on the 4500g with correctors… but it was the first time out on the water, so I will be moving the weight fwd in the hull.
Vid here…
//youtu.be/GGOR9bnNfo0
Niice Jim, well done ! …the iron jib seems to work well with no wind about … very quite 
Cheers Alan :zbeer:
Thank you for the video! Yes the bow is too high, and the leech of the mainsail is too open, but the boat move easily with this light wind. When do you think to paint she? After done that, you can test SWE-96 vs your firs boat to see differences and to improve the new boat…
Alan, why did you write “iron jib”?
Iron headsail means he thinks there might be a motor on board!..
The leech was open because after I finished sailing I noticed the head slug in the sail track wasn’t in…oops.
Two boat testing will be commencing soon. I gave my last boat to a good mate of mine for his Birthday… He purchased the RC gear on Friday!
Jim, you have done a dazzling project…
May I ask why you choose to paint the hull with epoxy based paints and take the extra weigth penalty, is it for durability of the paint scheme?
The epoxy paint was used as I know that it is long lasting and has the bonus of being a very slippery paint finish.
Cheers, Jim
Here is a new movie … I chose to leave the camera on the pontoon and concentrate on the sailing… It was very shifty with the puffs and you see a few knocks, but otherwise a very successful lunchtime sail.
I am amazed at how this boat tacks compared to the prototype one. Moving the keel back has certainly changed the characteristics for the better. It is more agile, faster out from the tacks and never seems to slow down even when you are throwing the yacht about.
The composite rigging is working a treat. I am confident now that it should hold the rig up in a blow, but it is still early days yet!
It actually “sings” a bit when you go upwind. I will try and get some good onboard footage and post it soon.
Ciao for now…
Hey Jim,
I have been following your build log and I must say WOW! It does also seem you are building in the perfect surroundings!
I am curious how far back you moved your keel form the previous boat? Was you prototype boat built using Claudio’s plans? The reason I ask is because I am currently building a AC100 and I too was thinking of moving the keel back from Claudio’s suggested position. Is there a ratio or maybe a percentage you could give me?
Thanks for your time, pictures, videos, and any info you can surrender.
Brian
Hi Brian,
Thanks for the comments. It is the perfect place, but not for much longer as the whole project is closing down, hence the need to push out a yacht with some future potential.
The design is based on one of Claudio’s, - The plan profile, and the rocker profile - as this was the closest I could get to the original SWE 96 and I used this as a starting point to get things going. However all the profiles are my own tailored to her bigger sister.
The balance on the prototype was never bad in any way, but because I am a firm believer in the big head mains, as the main head grew so I needed to change the CLR accordingly.
I moved it aft by 5mm and that was it! For a smaller head there would have been no reason to make this change.
From my experience these yachts behave very much like the full sized versions and a small change can make a big jump in performance. It is also why they take so long to build as accuracy plays a vital role.
Make double sure everything ends up where it should!
Cheers,
Jim
Hi Jim, great video she looks fantastic and sails beautifully even through she is not yet finely tuned, will be a real weapon… Also the best looking large head main I seen on a 120 … what’s the key in making that type of main ?
Cheers Alan
Hi Alan,
Thanks for taking a look and for the compliments.
The main building has been a trial and error process. Not being afraid to try something out and also to go to extremes and see what happens!
This particular main is the product of just that.
I went for it on the camber in the head and balanced it with a very conservative luff curve.
I am now just starting to get a feel for this Black art and I am on main No:4 using a Claudio based tool.
Also check out the battens. Notice the taper… As far as I know, no one else does this…
During the 32nd cup I had my own sail batten development project and have seen and tried a few things.
To work at their best, battens need to be soft at the luff, progressively stiffening up towards the leech. I cannot understand why uniform width battens are applied on model yacht sails?
Using this principle, the head on the main ‘pops’ from one tack to the other very nicely.
I now want to take this further and make a sail in some lighter materials and see what the results are.
I hope that helps.
Thanks again!
Jim
Very interesting footage. A couple of comments.
The video in post 75, the leach of the main looks very open (too much twist) visible when the boat is sailing close hauled directly towards the camera. My reaction was that the top of the mast may be flexing, even though there were no gusts obvious.
Watching the on board video of post 76, I see the main boom lifting. That would also lead to the increased twist in the upper leach (with loss of drive). It looks to me like you are not getting enough advantage from the vang. The vang is mounted about halfway between the deck and the goose neck. The vang would get a better angle and provide more leverage if it were lower down the mast.
The twist in the jib was hard to see, but was a lot less than the main. but seemed very close to perfect, maybe try just a tiny bit more twist.
We are snowed in and it’s too cold to sail here at the moment, so keep posting video for us.
John
Hi John,
Thanks, and you are right about the vang, but the reason is a bit off - I basically have a fixed mainsheet post and if I add any more vang it would hit the post… It is something that I will be modding to an adjustable one in the next couple of days.
Very eagle eyed!
Cheers,
Jim
Hi Jim,
Bloody clever cookie 
never thought about tapered battens in the head of the main … now it’s so obvious !!.. silly thing is I have tapered ones lower down in the main leech, as do few other 120’s.
You’ve just changed my mind back to square head main when I was about to go the other way, owe you a few dozen beers when we get to sail togther in Ravenna for that gem, thanks
You touched on camber saying that you “went for on the head” I had been working with Ben Morris in Autsralia on another project a while ago, when trying my hand at sail making http://www.stirling.saradioyachting.org.au/sailmaking.htm this guy is a artist who is very open (not black at all) anyway we were talking about cambers percentages & I had always been on the conservative side.
Note: the section on Ben’s site on “diagonal seams” is good food for thought.
Have a look at the attached camber calculations & tell me if you think they are still too conservative for a 120 or not ?
Cheers Alan.
P.S John we just got hit with snow today as well … time to get into the on-line sailing games 
Hi Jim
while appreciating the movie I got the impression that the butterfly setting up was some times difficult.
Whatching the film, I managed to get a frame onto which was possible to make a simple analysis.
1st - It is not clearly visible if it is mounted a boom counter weight
2nd - The jib boom anchoring is less than 25% requiring eventually increased counter weight
While respecting the ratios, the figures are relative to the picture dimensions and not the actual hull size.
Hope to be a usefull remark !!
Cheers
ClaudioD