Rig Tension and Rig Knowledge

[jviss]

My previous boat was a C36 (sold, by the way), which was a masthead, single spreader rig with cap shrouds, forward lowers, aft lowers, forestay and backstay with adjuster. Pretty well know, well documented stuff.

My present boat is a masthead rig with two spreaders; cap, intermediate, and lowers all coming to the same, massive chain plate; and a baby stay.

Any wisdom in baby stay tuning or adjustment? It's loose now. I have 15% B.S. on the caps, and 10% on the intermediates and lowers now.

Thanks,

jv

 

[BarryL]

Hey,
Is the baby stay adjustable? The C&C 35 I race on has an adjustable baby stay. 99% of the time it is 'off'' or loose. If we are beating into seas and the mast starts pumping we put the baby stay 'on' or tight. And that's all I know about baby stay.

Barry

 

[SG]

First, the extent of what you do with some of these features is influenced by how the sails were cut, how you use vang, outhaul, luff tension (halyard and cunninghams), etc. Your rig on that Tartan is probably pretty "stout", don't go crazy -- it's not a Mumm 30 ;^)))

The baby stay is usually used for a bit of "pre-bend" assistance to avoid having to over-tension the back stay to achieve this result. That's pretty important on a stiffer rig (I think) because you don't want to have really CRANK up the pressure unnecessarily to get the same effect.

Pages 33, or so.
http://www.riggingandsails.com/pdf/selden-tuning.pdf

The description by North sails is brief (The diagram is helpful as an adjunct):
https://northsails.com/sailing/en/2016/10/how-to-tune-your-rig

With a stiff mast, backstay tension translates primarily into headstay tension, controlling sag. A baby stay can then be used to add bend. The backstay contributes to bend as well, particularly once bend has been initiated by the baby stay.

Running backstays allow control of mast bend independent of headstay sag. A tight backstay will tighten the headstay and bend the mast. Tensioning the runners will straighten the mast.​

P.S. -- Our Hall (may they rest in piece) mast has a lot of pre-bend which is expected except when she's really off the wind. Our main is relatively large, yours is more traditional in terms of the relative size of the foretriangle vs. the main -- i.e., you have a larger 'J', J. :^))). We don't have a baby stay, but it's a multi spreader rig. I think the baby stay is more important with the larger foresail.​

 

[jviss]

Wow, thanks for the detailed reply, @SG. Lots to digest....

 

[LeeandRick]

Nice post SG. Quick, to the point, with facts and references. I've had that Selden guide, or a version, from back before the internet and you talked a rigger out of a copy. The reasons I'm commenting is to praise SG (there are no double likes) and to punch this back to the top, in case someone who needs a generic rig tuning understanding, missed it. Your mileage may vary, depending on your rig. Prost .