I’m thinking over construction ideas of a super light IACC 120 and seeing Jim’s amazing feat of reaching 365 grams with combined hull including internals http://www.rcsailing.net/forum1/showthread.php?5782-IACC-120-Fleet-grows-by-1-more-again/page2 it is clearly doable, however, the result means having a lot of corrector weights (approx 500 grams) to bring the boat up to minimum weight regulation of 4.5 Kg minimum, which seems a bit of a waste in my eyes.
Yesterday while sailing with a friend and talking over planning construction of a new IACC 120 for him, he said that he would like to have a Genoa instead of a Jib and then the penny dropped that is would be an interesting way to bridge the corrector issue on a superlight 120 by having another winch for Genoa sheet control.
Then started looking through Italian IACC 120 rules in regard to sail area C.7.2.1, maximum sail area is 80 dm2. Rules state that you can use one servo for sheet control (Main & Jib) or alternatively it is allowed to employ one additional servo (Genoa) for sheet control only, as a Jib replacement.
Reading the rules further under sail area it states under G.4.2: The Headsail surface shall not be lower than 35% and not higher than 55% of the Mainsail surface area. Then further under G.5.2 it further states: The Genoa Luff length shall not be greater than 80% of Mainsail Luff length.
Hmm … looking good lots of room to work within the rules.
Next started researching to see what has been done with Genoas on R/C boats and there is not much available that I can find only thing was a few pics on Vortex 60 which looks great.
Having absolutely no experience with Genoas on R/C would like to throw some questions out there …
What are the pro’s & cons of using genoa on R/C ? (imagining down wind would be a challenge)
Hi,
is a complicate matter to organise a proper working cicuit.
Is fantastic when works well and a night merry when is not.
Further, on reaching the Genoa cannot be controlled anymore as done with boomed jib , and the efficiency drop .
At the end, after some trias and nice looking shows, the boomed jib get back !!!
Apparently even on the future America Cup boats, the Genoa is banned !
Cheers
Claudio
Thanks Nautibuoy I will contact Larry and ask what he has, could not find anything on his site… Claudio you have not tried anything with genoa sheeting system ?
Found this on U-tube does any one know anything about this boats set-up ?
Claudio, I’m guessing when you say that future AC boats maybe without Genoas, that you are reffering to the possibility of having RC 44 one class design ?
RC44 what’s that ?
The film is just a demostrartion of how it is difficult to control the genoa and how is much time consuming in the manouvers, running is a disaster !!
AC Rules published last year banned the genoas only jib allowed !
Actually busy with AC100 and J class 130cm long
Ciao
Claudio
Yes agree the video is not a good example, it was 2007 and in rolling wave conditions, but it’s a starting point.
RC 44 is … well let’s say it’s the AC 100 version of the current AC boats design which are Russel Coutts design http://www.rc44.com/en/index.php
Russell Coutts addressing the 34 America’s Cup media Conference’ in Rome said that Bruce Nelson and Melvin and Morelli have been commissioned to develop new concepts for a multihull and monohull. A meeting will be called to which leading designers will be invited to discuss the concept.
Boats will have to be capable of sailing in winds of up to 35 knots.
Key is to avoid delay in the America’s cup racing. Need a boat that spans a wide range of conditions.
Race officials will be able to adjust the length of the race course to suit the TV schedules.
Coutts said that he expects that there will be regular events in 2012 involving the teams racing in the new class of boat.
There was a designers conference (closed) in two weeks after these statements in Valencia, but have only heard speculation since then ?
Just me joining the dots together the RC 44 kinda fits the bill and uses Jib and not a Genoa …???
Funny this came up. Right at the beginning of my build we had seen the genoa option in the rules and I wanted one but steered clear after some extensive discussions in depth with our full sized IACC sailmaker…
The general opinion was that a genoa would not make these yachts any faster and you would also not be able to ‘Point’ as high the same boat but conventionally rigged with jib boom etc.
I am not saying it cant be done… But you need a lot more forestay tension, runners, cunninghams, cars, pushers and a trimmer to do it!
Here is where it gets a bit spooky… The example he gave was…
In the beginning, the RC44’s experimented with huge overlapping Genoa’s… to no great effect! They sailed higher and faster with the smaller foresail. Hence they are sailing with ‘Jibs’… WEIRD!!
Even now, the Genoa’s on the Louis Vuitton V5 boats have been radically re-cut and are much smaller than ever used in the cup in 2007. (No battens at all I think…)
See where it might be headed… I don’t want to put anyone off, but it has been tried and as much as I would love a big powerful looking headsail, it seems that thinking is being re-evaluated in the sailmaking circles…
Just to round it off - Strange as it might sound, I sail my IACC 120 with an IOM JIb most of the time and it is very happy in all wind ranges with that setup.
Cheers,
Jim
Hmm … well Claudio presented the coffin on this subject and now you have dug the hole …the only thing left is to bury Genoa on IACC 120 idea … R.I.P
Now just waiting for Claudio to come up with a RC 44 scale or is he rethinling the new IACC 100 ?.. (thinking a planing hull with two Jibs here :tapedshut)
Ok Genoa is buried by complexity … but still looking for ideas with simplicity.
I’m now considering a double forestay arrangement on one of my 120’s to see if there is any performance improvement.
The idea is to move the Jib tack to the centreline of the boat, when beating you would be able to point higher, when running wing and wing you would have more jib sail area exposed to the wind (not shadowed by the main)
Further it is hopeful that we can remove Jib boom counterbalance weight, eliminate Jib topping lift which sometime causes tangles with spreaders and maybe improve down wind steering.
The thinking is to have a double forestay which is doing for the jib what the boom vang does for the mainsail - adjusting the leech tension. The concept is to lengthen the Jib boom so the pivot point is moved forward to same position of the Jib tack and then adding second forestay to the tip of the extended boom with bowsie to balance the double forestay tensions.
Alan,
The idea is intriguing, but if I understood well you need additional servo to create the jib hocking displacement . Assuming the feseability, the drawback is that the CE is also moving forward and backward disturbing the tuning setting.
Cheers
ClaudioD
Claudio, the CE would move backward & forward I had no intention of changing the sail plan …only extending the Jib boom, how can/could the CE change ?
I missed the point for a second servo ? my thinking was to move the Jib fairlead position forward to maintain the same Main & Jib boom travel as per normal i[/i] boom pivot.
All of the rig tension, whether from aft shrouds or backstay, is spread between the forestay and the jib leech. If you add another forestay, the same tension will be split three ways. Any tension on the new forestay will loosen the jib luff very quickly… not good.
I have seen a rig where the jib was tacked on the CL, and the jib boom at the same point, but there was a fitting there that acted as sort of a boom vang. There may be a drawing of it in the US1meter construction guide on the AMYA webpage. Page 46 of http://theamya.org/boats/us1m/pdf/us1mconst.pdf Can’t be used with genoas.
You are still going to be working with an amount of rig tension, and have to divide it up between luff and leech however you want. Want more tension, crank on more backstay if you can handle the mast bend.
Hi Alan,
probably I miss totally the concept, sorry.
The actual AC10 champion was winning twice the French Cup just because he used the boomed jib against the others that used the classical genoa and related manouvers complexity.
The boomed jib can easily change board and it is a much faster manouver compared with a genoa. Probably, in term of overall effinciecy are equivalent.
Cheers
Claudio
Hartaluminium, mit zwei Kugellagern, für meine Bäume eingerichtet, Schotführung für “Butterfly”, komplett mit Kleinteilen.
Jib-boom fastening aluminium, with two ball bearings, prepared for my booms, sheet lead for “Butterfly”, complete with small material.
Vit de mulet pour le foc en duralö avec 2 palier annulaire à billes, concu pour mes bômes, y compris contuide des écoutes pour le “butterfly”, et menues piéces.
Hi Hew, yes that is the idea, I understand what you say about balancing tensions, the AMYA guide and Claudio’s picture of the hinge for radial boom seems like the same solution, both sophisticated & the German system over engineered & ridiculously expensive (which is normal)
As my #2 hull is about to be retired, I will take the plunge and try the concept on this hull and report back when completed and tested.
lots of room to work within the rules.
only thing was a few pics on Vortex 60 which looks great.
