Slieve McGalliard wrote:

Hi Jef

Thanks for the information on your jibs. Where I believe you are on the right lines, I feel that you have too much cloth in the jibs and are not getting the camber to produce the drive you want, particularly for a light, easily driven hull. A flat/ horizontal shelf will not work in a jib, and is not ideal in a ‘mainsail’ panel either. I see them as poor design which is simple to understand but does not produce the best result. I use 45° shelves in the jibs and have further tightened the leeches.

 The photo in PBO was taken over 2 years ago and things have moved on since then. Yes, you do see little sheetlets, but they were a temporary experiment and I have re-cambered the sail so they have gone (for the moment). There aren’t any battens in the jibs and I guess you are looking at the webbing batten parrels, but they have also been removed from all but the bottom and top battens and replaced with combined batten parrels/ downhauls, making for a simpler and more rigid rig.

The secret of the better performance is not in putting in the right parameters and accepting what you get, but making sure that the parameters you put in gives you the final shape you are looking for. I look at the photos of commercially built cambered sails and see shapes that will not give the best performance because the sailmakers apparently do not really understand what they are trying to achieve. I feel there is a lack of understanding of basic aeronautics and that effort is being used to produce ‘pretty’ sails that will sell well rather than efficient sails that will sail well. Yes, they are better than flat sails or hinged batten sails, which isn’t difficult, but they could be much better with slight changes of shape.

I built Poppy’s sails with leech lines on all panels, and have now further reinforced the leech areas even though it is not strictly necessary. It actually is quite a sophisticated sail design which is why it is taking so long to write up. (The write up is not helped by me trying to include the background thinking for the benefit of future experimenters).

In haste, as ever,

Cheers, Slieve.

Hello Slieve,

You made a post on the other thread about "which sail to choose" and when I  indicated I would probably go for cambered panels and not split junk, you "pleaded" for your rig not to be discounted.

I was very enthused by the PBO article and started to waver from my increasing preference for cambered panels towards your rig. Your latest post finally starts to open up the intricacies of your design which I still have not quite worked out, so I am still very much looking forward to your publication of your "improved" design before making my decision. My aim is to find the "cheapest" and most "convenient" way to aquire a vessel 28-35ft  with some form of "reliable" junk type rig on board and then go in for the RTI, just for the experience. Being of an age and without huge sailing experience, physical and mental exhaustion becomes an increasing factor in how one chooses to go sailing AND enjoy it, AND have friends on board who remain friends after a trip! or should I say voyage. Bermudan rig does not do that for me.

The very first JRA rally I ever went on was from Warsash and on POPPY and I knew so little about the subject I was rather overwhelmed by my inability to ask the right questions. What stands out in my memory is the total relaxation of that trip. No nasty heeling surprises, no nasty gybing etc. Unfortunately "the general public" never like to be teased about the fact that what they do is either "different" or "does not look right(pretty)" according to the current "fashion" as dictated by the current boating press.

"I have not tasted it, therefore I do not like it" was what I encountered with my new cheeses! Plus ca change, plus ca ne change pas! I very much look forward to new spec coming out.

Rodney W

Slieve McGalliard wrote:

Hi Jef

It’s interesting that you are not getting good performance form your split junk. It would appear that the design of the jibs is not working well. You mention shelf construction and an 11° sheeting angle, but you don’t explain the type of shelf used nor mention the amount and position of camber in the jibs. The design of the jibs is the main key to the rig, and that is one of the reasons I have been so slow to write up the details. Get it wrong and the performance will not be good. It would be interesting to know more detail about your jibs.

Regards, Slieve.

Slieve,

Details of my jibs are as follows: shelf close to a Naca 0015 profile with 8% camber and its deepest point at 35%. Making the sail, I had to flatten it a little bit in the nose because of the wrinkles I got.Panel height is 66 to 70cm.6 panels. Setting up the sail in my garage ( the 3 lowest panels) with a fan in front I measured in the center of the jib an angle of 27degr. with the batten. Making short battens at the ends of the shelf foot did not improve the form of the jib.

Looking at a picture of Poppy's jiblets in PBO page 60, i see  longtitudinal battens and a kind of sheeting to the middle of each jiblet. Is that the secret of a better performance?

To improve the performance of the rig  and avoid diagonal creases, I have in mind to fix a  kickingstrap to the lowest batten of the jiblets in use (extra work when reefing). Also i think to open up the hem at the lee of the mainpart and stich in a kevlar rope  to prevent streching of the sailcloth.

Regards, Jef.

Hi Jef

It’s interesting that you are not getting good performance form your split junk. It would appear that the design of the jibs is not working well. You mention shelf construction and an 11° sheeting angle, but you don’t explain the type of shelf used nor mention the amount and position of camber in the jibs. The design of the jibs is the main key to the rig, and that is one of the reasons I have been so slow to write up the details. Get it wrong and the performance will not be good. It would be interesting to know more detail about your jibs.

Regards, Slieve.

Last winter I have made a split rig on my proa, a mix of the sailplan of poppy and pingpong. The mast is in the same place as before and i put 33% in the jib part.Now I have the possibility to use the bm rig or the sp rig. The boat is with both rigs perfectly in balance .Clause hauled the jr is slower but much relaxed to sail. In 3bf and + you need a wet suite and spectacles when you sail the bm rig, while you don't need much protection sailing the jr. In the jib part I used the shelf construction with 11dgr. sheeting angle which is too wide, the sail starts fluttering coming close hauled. The main part has the barrel construction with 6% camber develloping  diagonal creases when you tighten the sheets. May be the ripstop nylon I used streched too much. In the coming month I want to change the the main part to  shelf construction and the sheeting angle of the jib part to 7 degr. Next year i hope to sail fasterwith the jr than the bm rig.

Jef.

Thank you Slieve, this was food for thought. The Swedish/ Norwegian LYS handcap system does not seem to take sailshape or number of edges in consideration. When ED was measured, the measurer used a gaff sail as template. The funny parts started when he wanted to mark the upper point of the sail on the mast and the outhaul point on the boom. He was ending up with numbers of infinate walues, but as he said: "We had a committee meeting were common sense prevailed". "In other words, wet your finger and stick it up in the breeze," I asked. I understood that they had consulted the sailing brigade in Tønsberg where they had more than ten Mikkel 32`s in the early 80`s, and they felt that a LYS handicap of 1,06 was the normal for a bermuda rigged wersion. I got a LYS of 1,04, but I think that will be changed for next year. Having searched the starting and finishing lists of ICR handicap, I should end up sailing with Poppy in ICR Division 8B if the LYS handicap is used. I spotted a Hallberg Rassey 29, Lys 1,04 was rated 0.901. I think, in all honesty, that I should have litte problem in keeping up with a HR29 given winds of more than 10 knots. The racing has led me to number of small improvements that has had good effects on the windward sailing, + driving ED to the max in a make or brake mood, really helps. I was out sailing today in a cold breeze of 10-16 knots, and I am still confused of what is the good tack. Today it was the port tack, believe it or not.