Hi Don, that servo is an option where you can control the main leech tension hence change twist while sailing 
Cheers Alan
Thanks a lot Alan,
It appear very complicated at first, but I’ m sure that I can redraw more clearly the film images.
From what I have so far understood, the Ring method it is also used here . I need some concentration to work around all the images collected.
The pulling idea is not bad since can offer some slack to the sheeting, but what it is doing this job ? Is not eventually the third servo ? !!!
The question is : what sort of winch is used capable to support a 90mm drum ? Is eventually an RMG ?
The Genoa changing board is made in 3 seconds, rarely in 4.
Cheers
Claudio
PS : Small updating of my previous drawing :
About the drum diameter & deck sheeting :
Do we know what “you” have to do to tack? Do you throw a switch as you pass head to wind? Do you control it like a two channel, just throw the rudder over? What does the skipper have to do to tack? There may be a clue there.
Don
A closer look at Claudio’s last post. Where you labeled stuff. The jib sheet seems to end at the ring. Maybe there is no control over the jib sheet. Is it a fixed length and the position is determined by the “traveller circuit”? I’m beginning to think that this is a “less than optimal” system. It was designed more around number of servos rather than good sailing. I may be wrong. I’m going to go look at the videos again.
OK I’m back. I don’t think the jib shape is that good. When thy are reaching the bottom of the jib is hooked. The jib sheet should be shorter and the ring further back.
Don
This is what I was able to do up to now !
The jib once on the center line of the boat, the wind push the jib to change tack and the genoa guidance line need only to be pulled the go in close hauled . This is what I understand so far, except the dotted line (blue) that I did not find where is coming from and why jump from one side of the mast to the other as marked in the video !!!
Probably Alan shall explain again taking some refrence image !
The green line is driving the genoa sheet (black) and the Main sheet that control the boom . An extension (light blue) is going to a servo in order to control the Main/Boom tension. The Wang function not understood !
The green line and the red line are linked therefore the Genoa cannot assume indipendent position from the main Boom , the only variation for the Genoa is to adjust the track rail equipped with an eyelet
Cheers
Claudio
Hi Claudio, looks pretty close to what I understood excepting the blue dotted lines as attched to the winch, as is the main sheeting.
This was the part I had little trouble comprehending (technical German is testing at best of times) the winch has a brake function for the Jib going about, what it is and how it works ? was lost in my mental translation and what confused even more is that the main sheeting is not affected by the braking affect, had me imagining there are two drums on same winch (one running inside the other) this is when the “servo computer” word jumped in my head, this maybe what controlls it.
The Vang is a normal, excepting it is shorter than normal (maybe spring loaded) and the main sheeting runs from the winch up to the goose neck and along the boom and down through the main traveller in the cockpit as its end point where it is then attached to servo (starboard side) and is then used to pull the boom down or release to fine tune main leech tension under sail (as in your drawing)
There are a whole host of other really great ideas which I won’t confuse you with now, but planning to take couple days off work (this week) and meet with the guy who designed it … can’t wait to get my hands on one.
Quite a number of guys are using RMG’s, but I’m not sure if it is absolutely neccasary, will find out more when I can and let you know
Cheers Alan
Hi Alan,
According to what I was reading in a french site, are used optical micro switches to stops the servos , when I did not understood.
I got confirmation that the winch is a Smartwinch from RMG, and the drum is 90mm dia.
The black lines visibles and clamped on the roof are simply a control type Cunningam, see this picture :
Others interesting images here, like the cunningam hooking and turnbuckles :
Cheers
Claudio
Evening all, after much head scratching etc (seem to be doing alot of that recently) I think I’ve worked it out.
I think when the word ‘brake’ keeps coming up on the various translated sites its a google translation anomoly.
If you go back to Claudio’s 44/45 post (first video of sprinta) the best example that I could see was around 1min 20 seconds. It’s a light blue hull, sail number GER 007. You’ll notice that as it transitions from starboard to port tack, the main sheet goes completely slack before its taken up again as the genoa is re sheeted.
In terms of control, with our standard set ups, we generally go from stick fully forward when running before the wind and then stick fully back for beating. As far as I can work it out, with the sprinta stick fully forward & fully back are both beating positions - one for port & the other for starboard tacks. When the stick is central / neutral position, the sheet attachment point on the circuit is midships, forward of mast stays etc.
Hope that lot’s understandable - once I’d got my head round the principles I was totally amazed at the principles involved. I think Don’s comment about it not providing good sheeting for genoa is a fair one but I have to say it’s an extremely good compromise.
Regards,
Row
I hope nobody thinks I am saying that this is a bad design. On the contrary I think it is a stroke of genius to design a system like this. All these things happening with one servo is amazing. I would like to turn him loose with two servos.
Don
Still I did not managed to understand this picture concerning the blue line role !
Is anyone telling how it work ?
Further from that picture it is clear that the genoa guidance line is keept in tension as such to bend the shroud lines around the turnbouckles
Thanks
ClaudioD
I certainly don’t think your saying it’s a bad design - like you I reckon it really is ‘…a stroke of genius…’ and I apologise if that was the impression given. Like you I do think the genoa shape when reaching could be better but at the end of the day the system works and the mechanics of it would appear to be achievable relatively inexpensively. The winch that Dick Lemke mentioned in an earlier thread was from another German site (I thought I had a link for it) which used a pair of conical shaped drums and electro-mechanical clutches if memory serves. It was something like 450 - 500 euros, so about the same in dollars I guess which must be at least double the price of an RMG winch using the sprinta set up.
Claudio - I’ve watched that explanation video several more times now and referred back to your own schematics of the system and I’m still no nearer to understanding it. Alan’s post 59 refers to it as ‘brake line, also used for mainsheet control’. Only explanation that makes any sense to me is that the line is purely a simplified schematic of the guidance circuit - the pair of arrows pointing at the servo indicating that as one side releases so the other tensions. We need someone with fluent German!!
Regards,
Row
Hi Row,
there some thinking about the overall weight that is of 8 kg while the ballast is 5 kg, thus 3 kg are used for the construction for a boat lenght of 120cm.
Really is a very heavy model if you compare with an AC120 that is almost half of the weight or a class M where the complete model will be around 1.3 kg escluding bulb of 3.2kg and 129cm long
Why all that !
simply, if the genoa would be employed with a 100 cm long model, this system shall be sufficient light to be compatible with the overall displacement.
Actually my study about the 43-900 is suggesting one additional servo of 60g. The system will allow semi- indipendent functions with the possibility to trim the genoa by using only one of the two sustem settings.
Some additionl weight 40g will be used for the battery with higher capacity since it is expected higher consumption.
Thus altogheter 100g are added that can be reasonably supported by my design.
The lesson learn with the Sprinta is that the genoa main circuit shall use a deep troat drum to avoid the risks of loosing the sheet if some slack is introduced.
I know that a friend of my on the Jclass used a sort of driven motor roller to expell the released sheet out, but far too complicate for a small dismplacement model.
So, for the time being, I stick to my design options while searching for other solutions of course !!
Cheers
ClaudioD
sorry for the bad quality of my film taken with my old photocamera allowing 20seconds filming.
I have modified the set up as previously described on the Genoa 3 drawing above.
Watching the red/black dot on the sheet you will see going and returning back. The chrono will help to see the time !!! .
The dot stops at 13.5 cm back from the forward face of the mast
The digital servo winch is the Eurgle 22y 60g
The lenght of the circuit, from left to right, is 390 mm and it take 3 seconds. this is the maximum lenght that the actual drum 32mmID can handle.
include the corresponding dimensioning of the genoa in this drawing :
Cheers
Claudio
Here’s my best guess … meet with the designer this coming Thursday …will update Friday 
Hi Alan,
nice view of the cunningam arrangement !
After testing , I revised my drawing also because in spite of the band saw arrival, outside is raining again cats and dogs. Yesterday we got a very powerfull storm, see the beginnig picture from my balcony. Lightinings just stroke close to the house because of the tall crane installed for a new building construction. Computer and others appliances off for a while !
It is not excluded that this setup will be the final approach unless further inputs are knoledged. Guiding tubing not illustrated to avoid complicated drawings.
Cheers
Claudio
Hi Claudio
I hope you don’t mind a comment or two. I’m not even sure I’m right but this is how it looks to me. The “ring” takes the place of the jib lead block(JLB) on big boats. One of the functions of the JLB is to allow you to pull down on the jib sheet to tighten the leach. On your drawing if the ring is free to float(slack genoa loop) you won’t be able to pull down. The solution is a track of some kind but that starts to get silly. The next thing I see is that as the ring moves forward the jib sheet will slack off. You won’t be able to tighten it because the main is already close hauled.
I’m beginning to think that this may be only a little better than the Sprinta system with the added complication of another thing for the skipper to do when tacking. I think that in order to have realistic genoa sheeting you will need three servos which would mean that the boat would become a real pain to sail. Using the basic Sprinta system as I understand it so far you can tack using a single stick. You can’t control the jib shape that well and the main sheets out when tacking(I think the main sheet brake is to solve this, however it works??) but the boat sail nicely. We have seen the videos to prove this.
I think you should continue on the way you are going(two servos) and see how it goes. At the very least it would not be a big job to convert from your system to the Sprinta system if it doesn’t work out.
I’ve got a couple more things to get out of the way and then I will build a mock-up to see what I can come up with. If nothing else it’s good exercise for an old(ish) brain.
I really want to see this work but somewhere in the back of my mind there is the thought that if there is a way to do it effectively it would be already be in common use. We have been preceded by an awful lot of creative people.
OK I’ll shut up now
Don
OK I’ve thought for a while and it’s quite possible that the ring resting/lock position could be a dock adjustment. This may be the case for more adjustments. Also once the boat is set up for close-hauled, tacking would only consist of moving the genoa loop. Any more trimming could be done on the next beat. This is looking better.
Don
Hi Don,
I’m not sure to have understood your remarks.
Probably an enlargement of the drawing may help. see PDF file below
In principle there are 3 controls for the genoa in Close Hauled :
- the genoa guidance circuit (Blue line) that allow to move the “ring” from left to right or at any intermediate position in accordance to the dedicated winch
- the main/jib circuit sheet (green line ) that is directly connected to the genoa and main sheet defining the opening degree from close hauled to running
- the rails that allow to adjust the tension of the genoa leech or any other genoa shapes.
Certainly a deflection may occur on the Ring guidance circuit sheet inducing a slack.
In the drawing , by purpose I shows a less tighten Genoa in order to better highlight the margins available for full thigh.
It is not excluded the use of a Pulley/Spring to keep slight tension to the genoa guidance cicuit .
So , during sailing it is possible to play on 2 sheeting systems , the second of course affect the main too since is the typical sheet control of all models.
As I said this is my starting point, and modifications may still occurs as the design will progress !
Hope will be more easy
Cheers
ClaudioD
Hi Claudio
For the genoa loop I’m concerned that there is going to be a large"up" force at the ring. If you are planning more tension to solve this, what are you going to use as the forward turning points? You have them marked as black dots on the drawing. They are going to have to hold the loop down and pass the ring.
You have to remember that I have not sailed on a real boat so my understanding of how jib sheeting works is a bit lacking. I always think that the real boats that I see on the water here, have too much twist in the jib. Maybe that’s the nature of the beast?
Don
The rail is equiped wit an eyelet and is this device that keep and retain the genoa to go up when in close hauled position. Same device as in the pictures below
ClaudioD
Hi Claudio
I’m going to give up trying to explain. If you’re not understanding what I’m talking about it probably doesn’t matter. I’ll just lurk until I think of a way.
Thanks
Don