J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Rig Tune

Bob - We have the same thing with our North main. I have found that the general rig tune does not work with the main.

Here are my observations (right or wrong):

Strong Breeze: 41 upper 37 lowers tight back-stay (1/2 inch of threads above/below the center bolt) - We found that with the lowers tighter the pre-bend is not carried nicely from the base up, but more from the lower hounds up. But loosening the lowers and tightening the backstay give the rig a better overall arc - which helps to flatten the lower area where the speed bubble is most pronounced.

Lighter Breeze:35 lowers 37 uppers - backstay is much looser - 4 inches of sag (2 inches of threads from center bolt) We then vang sheet the main to keep it from twisting into the slot as it is eased.

So these are somethings that we learned this year - we will try them again next year.

It would be interesting to see your thoughts on these settings.

David
#397

I have not had any issue with the speed bubble with the main I bought this year. I do find that outhaul and halyard tension has a huge impact on draft depth-I've been carrying a little more tension recently, to good effect. On the halyard-I take all wrinkles out of the luff in flat water/almost any breeze.

I have found that overall rig tension helps a lot to flatten the main when breeze is on or building-in the first race at the NA's, I think (judging from photos) that we had the flattest sail on the course.

Like Fuzzy, we used to keep the uppers and lowers at the same tension generally in the 38-41 range depending on breeze. The White/Bartlett tune is much looser shrouds and somewhat tighter headstay. But it might be worth trying, something new since we've been off the pace the last two weekends. Our setup is generally main halyard just tight enough to remove wrinkles, outhaul fairly tight, and no vang or no backstay tension up to 15 knots true upwind.

I can't help it; I have to ask the question:

Is the main is getting back winded predominantly by the 163? Wouldn't that argue better performance by a 155%?

I sail PHRF and I have bought a Dole carbon fiber main this year and have maximized my roach (within the tolerance of Nova Scotia ASPEN rating)...sorry guys. My Mylar 163% is bagged so now I am now faced with a decision that all PHRF sailors face, do I take a hit and sail a 163 or get a 155? My concern, even before I read this post, was the effect the 163 had on back winding the main. Anyone have any thoughts?

Thanks
Jason

Jason - the main with the rig properly tuned works well with the 163 by design and isn't back winded. I had the "speed bubble" issue with my 2007 North main because it took me a while to figure out what the correct tune was for that sail. The 2008 Main I had no problem tuning for at all. Not all sails are cut the same shape even if they have the same sail area, thus the tuning difference.

If you go with a 155, you should find that you sacrifice some light air performance, an area where the J/30 needs all the sail area it can get. For PHRF only racing, the 155 is probably the best compromise if you take the penalty with headsail area from 155 base to 163.

Keep the 163 "bagged sail" as it will help you in real light air. How about you race OD at the NAs in 2009? We had one Canadian boat this year and could use another.

Three races this past Saturday in 15-19 with gusts to 24. Six of eight weather legs were #3. One leg would've been better with the #1, while one of the two legs we did use the #1 was a mistake--way overpowered. Using a tighter rig: 40 uppers/lowers (Using PT-2 and above chart that's 2000 lbs), 15 turns on the headstay, six on each backstay. The 'speed bubble' in the main was gone. We also played the backstay a bit and had it on hard enough to invert the main on the leg where the #1 was a mistake.

Speed and point were good. I'd say we probably had a bit too much tension on the lowers. And, while I'm not going to throw the tuning guide away, I do think I'm going to set the main up to eliminate the bubble.

[This message has been edited by Bob Rutsch (edited 10-22-2008).]

I feel like I'm missing something. I see bills chart that lists the model "B" and the PT-2. However the model "B" doesn't seem to go above 43 for 2000lbs.

I tuned mine with the model 90 in the hyperlink. I also referred to older posts regarding shroud tension and they all concurred on 44/45. Is everyone else using the model "B" which renders a lower (40/41) number? Or am I too tight?

44 for the model 90 is still within range, correct?

http://www.loosnaples.com/how-to-use-90-amp-91-tension-gauges-pg-13.html
http://j30.us/ubb/Forum10/HTML/000356.html

[This message has been edited by MangoMadnesss (edited 10-21-2008).]

[This message has been edited by MangoMadnesss (edited 10-21-2008).]

[This message has been edited by MangoMadnesss (edited 10-21-2008).]

Rob - the conversion chart is direct from the Loos web site. I just deleted the other models so there is less confusion. The PT-2 scale only goes to 40. The Model B (which is the Model 90) goes higher than the PT-2. You'll find the tuning you have is very tight and I think most don't tune the rig that tightly.

Actually, when it's blowing stink, tension of 2000+ (I go up to about 2100) can be very fast.

This discussion would be easier if everyone referred to pounds of tension-trying to reference the various calibrations gets confusing...

I don't do the headstay tightening thing when I have the #3 up-my theory is that keeping the jib with a bit of sag puts more power in the jib to punch through waves, and provides a wider groove.

so these guys are too tight? (hyperlink)
http://j30.us/ubb/Forum10/HTML/000356.html

On a side note I was surfing sailnet and alot of people argued the point that during the americas cup the boats have their rigging as tight as the rigging will allow.
I don't know if its true, I know its a one time race and they're pushing the limits anyway, and I know why we would adjust ours to maximize trim, however keeping it tighter would seem safer.