Rig tuning advice

[Alan Gomes]

Alan, do you have a backstay adjuster?? If so I would keep the rears fairly loose , I pretty much stop once the stay straightens with tension, this allows the midpoint of the mast toned forward flatting the main, I inly tighten the uppers and inner stay for racing in 15 knots true or more , I also have running backstays for upwind in 10+ knots of true wind

Thank you, Brad. This is actually very helpful. I do indeed have a backstay tensioner. This confirms my thought that I should back off on those aft lowers compared to where I have them currently set, which is at about 8% of breaking strength. That is definitely tighter than what you describe and considerably tighter, I think, and how I interpret Ericsons guidelines.

i’m a bit curious about what you had to say about your uppers and in-line lowers. Are you saying that you only tension them up before you head out to race, and then relieve some tension for when you are just sitting at the dock or just out day sailing? What does your default setting look like?

 

[Alan Gomes]

I sent a thread link to a friend and professional rigger for comments.
His comments seem useful and even a bit wry, and do indicate that tuning is not, IMHO, completely a science.
There seems to be some 'art' in it, too!

"That is one convoluted discussion. As usual the manual that comes with the boat seems to be lacking some information.

From what it sounds like I think he's best sticking with the higher percentages as suggested by Mr. Toss. Shape, balance and the ability to keep the mast in column when hard on the wind in about 15-20 kts. of breeze are the final guiding factors in rig tune. It can be difficult to tune when you don't have directly opposing lower shrouds and various wire sizes, ask R___(a mutual friend) how much I love tuning his rig. Even professional riggers disagree on how tight the rig should be, as long as everything stays in column athwartship, and you get a little tip fall off to leeward in the big gusts, there is some discussion as to how slack the leeward side should be.

I tend to go with higher tensions, as long as the boat's structure can take it. I prefer to not have the rig subjected to the shock loading that can happen when tacking in higher winds. I also prefer to have a little bit of a bend in the mast that can be adjusted with backstay tension. When you have a rig with "in-line" aft lowers it can be difficult to control the bend and they don't really contribute that much to the fore and aft shape of the mast. Single spreader, fractional rigs are tricky; in my opinion they're best left to trailerable boats.
Just my $.05 worth of comment (inflation values) "

Please pass my sincere thanks on to your rigger friend, Loren! This does help to confirm the direction I think I want to go with this tuning.

By the way: I am reviewing that old Brion Toss video that I have not looked at in years. (I had archived that old video onto a hard drive that was sitting in my office. I just retrieved it this afternoon.) I took careful notes on it and have relied on those, but watching it again as a refresher may prove helpful.

 

[Alan Gomes]

OK. Thanks.

I think Ericson‘s point in that document is that the fwd lowers are there to limit the forward bend of the mast at/below the spreaders rather than attempting to keep the mast in column, which the in-line lowers would help to do. I’m supposing that is why they say they are not concerned about those going slack, whereas the uppers and the forward lowers should not be so loose on the leeward side. At least that is how I am reading it. But I am not certain what that translates into exactly as far as a specific tension goes.

Oops! Please correct the first sentence to read “…AFT lowers are there to limit…”

 

[Brad Johnson]

Alan , I keep the uppers Tight enough that the leeward shroud in 10 Knots of breeze Has no tension on it , not flopping but no real tension, once I get that then tighten or loosen the lowers to keep the mast straight, IMO excessive fighting just is driving the mast down on the compression post and could do damage

 

[Alan Gomes]

Alan , I keep the uppers Tight enough that the leeward shroud in 10 Knots of breeze Has no tension on it , not flopping but no real tension, once I get that then tighten or loosen the lowers to keep the mast straight, IMO excessive fighting just is driving the mast down on the compression post and could do damage

Thank you.