Most of the current owners have concluded that rig tension is not the most important factor in boatspeed - the aluminum mast is so stiff that tweaking does not seem to pay much of a return. Forestay tension and jib halyard tension upwind, and leech tension both upwind and downwind, are much more worth the attention.
Leech tension is of course controlled through sheet, vang, cunningham and outhaul.
Forestay tension is controlled primarily by the mainsheet, but when you want a tight forestay without getting an overtight leech, chocks offer the best adjustment - chocks leaver the mast aft, and that stiff sleeve keeps it from inverting. Thickness of chocks has a very direct correlation to force on the forestay.
So here are base settings. I believe most owners start with similar numbers for rig tension:
- mast butt in middle of track (note that the bar blocking the front of the butt in the track often breaks - make sure it is solid)
- 1/2" chock in front of mast
- 25-35 on the uppers (loos gauge numbers)
- lowers very loose - deflecting 2" at dock - they should just hold mast in column when underway (sight up mast while close hauled)
I typically sail with a crew weight of 470-500 in serious races, and go for the looser end of the range on the uppers up to about 15kts of wind. Over 15kts, I'll typically put another 1/4" block in front of the mast, and may tighten the uppers 2 turns if it can easily be done (on-water adjustments are not easy, so if it's not convenient I don't feel too much urgency up to 20kts).
Before leaving dock on a heavy air day with chop, or sailing shorthanded in breeze, I typically put 1"-worth of chock in front of the mast (gives a very tight forestay with ability to twist off main), tighten uppers to 35 on loos gauge (I think other owners go as tight as 45?), and snug lowers.
(Worth noting that in the beercan races I typically have 350lbs crew weight, and may start out with tighter settings if breeze over 15kts is expected - though again, chocks would be what I would adjust
Very interested in what others have found.
After starting this thread I noticed another on the same subject (Headstay Tension Downwind). Oversight on my part. I notice, in any case, that Justin and I have different opinions about a few things. Several others in common, though. Will suggest in the other thread that people read this thread, and vice-versa. Interested what consensus we come to. Please post your experiences.
We're sailing #70 with carbon spar & Hyde mylar sails. Still learning the boat. Started out with lots of rake (lengthened forestay) & the uppers set at 40 on the Loos gauge (lowers quite loose, with about 2" deflection, as seems to be the consensus). Had a light day yesterday, so backed off the uppers two full turns--but at the end of the evening had a puff @ 12-15 knots. With the chute up under this rig we experienced severe lee helm, so we'll be resetting the uppers at 40, which seems to work well in the winds we've seen (nothing over 20). Does the carbon mast/mylar sail combo (the sails are gorgeous, btw) need more rake & tension than the older rigs?
Matt.
The carbon rig absolutely needs mast butt futher aft and longer headstay than the al mast. The aluminum mast struggles to get any prebend. The carbon mast prebends and so the center of mast bends fwd. To move the center of effort back to compensate = longer headstay etc.
We are all still learning on the carbon rig tension. I have not found that the tension needs to be greater than aluminum. Good chocks are key. Otherwise I have found that I am sailing with a tad less tension than aluminum...but still learning.
Do new stays and trurnbuckles come with the carbon mast ordered through Rondar? If so, does the headstay already come with a turnbuckle or do we need to get a rigger to instal that after it arrives?
Also, I thought that I had heard that the new mast comes with halyards. Is that true?