J/30 Class Association Forums J/30 Forum Racing Tools and Techniques Shroud Tension Tuning

Hi All, I'm having trouble establishing satisfying settings for Light/Medium/Heavy air that provide consistent winning results in our PHRF night races.

Following the "Rig Tuning" guides saved under Info, specifically the North Sails Quick Reference Guide, have been questionable.

North Sails Quick Reference Guide – Version 1.0
Wind V1 (Caps) D1 (Lowers) Headstay turns from 0
Base Setting 1050 950 15
Light (0-7) 450 250 10
Medium (8-12) 1050 950 15
Medium/Heavy (13-17) 1600 1600 20
Heavy (18+) 2000-2200 2000-2200 20-30

We've been following the Base Setting to start, results have been okay here. However on both Light and Heavy ends of the spectrum these numbers just don't seem to work?!

Light - 450/250 makes my shrouds complete noodles, not just on the leeward shrouds but on both sides of the rig, to the point that it just does not seem feasible. Can you guys share what you find has won races in Light?

Medium/Heavy - We've also tried bumping up to 1600 for more spirited nights but find that the sail just seems to be choked. We've had better success just leaving the Base setting for these conditions. Note, there is typically a good deal of chop when the wind is here, have had limited nights with flat conditions that might warrant a tighter rig. Thoughts?

Heavy - 2000 just seems to be WAY too tight on the rig. Perhaps I'm just nervous about high tensions, I understand the rig is rated for this, but it just seems too tight. Note, in these conditions we're typically reefed as our smallest jib is a 140% (anyone have a serviceable #3 they'd like to sell, let me know)

Couple notes on our setup. Rigging is 1/4". Main is a Quantum from around 2010 era, not bagged out, one full batten three half battens. Head sail is a 161% UK from around 2010 era as well, decent condition not bagged. Second head sail is a 140% North Sail, unknown year, fair condition. We have a roller furling system installed, don't use it for racing, but head sails use the foil.

Due to different Loos Gauges (I have the Model B) out there, please use pounds (lbs) of tension in this thread if you can or clarify what gauge you are using.

Looking forward to see what can of worms I'm opening up on this topic!

Here's our numbers though not in pounds; you'll have to look up the conversion from the info on line. We have a pro style Loos gauge
Our numbers are a place to start as we fine tune based on mast shape and sea conditions

Wind 0-6 uppers = 20 ish lowers = 15 ish (some would say that's too loose. We think it fast
We raced last night in 7 -8k winds we set shrouds at 30 and 25. Uppers were a bit too tight. Yet we won OA. The boat was fast and sailed above our targets up and down wind.
Our base setting is 32 -27 for 10-12k. Again a starting point
14k we set at 36 -30
above 16 we set at 41u and 40 on lowers w/shortened headstay

We race with strictly North sails for serious OD racing
We have some old Quantum sails for banging around on beer can racing

One other thing. If you are sailing in a lot of heavy air and chop to the point you are cranking on your shrouds, I would recommend that you make sure your bulkheads are solid and dry. I have a newer boat, hull 529, and still beefed up my chainplates. Drawings of our chainplate mods are on this web site under "info", J30 drawings and files

Thanks for the intel Russ, I'll look into this. One question, what diameter cables is your standing rigging? I'm looking at the PT-2 Loos Guage label and some of the numbers you're stating are well below the chart for 1/4"

https://loosnaples.com/images/pt-2_Label.gif

1/4 "

We race with all NS similar to Wildcat and our tuning is very similar to the above. I would add that we leave the headstay at max length until 18 knots, then put turns on after that. We tend to be on the extreme at low end and upper end with tension of standing rigging - . Super loose in light air, with leeward shrouds like a noodle. In high winds, we go up to 42/43 on lowers and uppers. We also tighten turnbuckles on the backstay in over 18 as well to allows for enough backstay tension. The tension on the backstay for breezy conditions does not allow the backstay to be eased enough in light air so a light and heavy air setting for both backstay turnbuckles is needed.

I have found that if you reef the main, it is very difficult to point. Some boats in OD get faux reef points that meet the rule but can't be used as they feel they will never reef the main while racing.

Take some pics and post them and I'm sure you will get a few opinions on this forum.

usa1136 - Are you measuring 42/43 using the Pro PT-2 (coil spring) or the 90 Model B?