Rig setting process, please forgive me for putting it here

[danstanford]

I know this is not a sail trim question but it is related and all the people interested in sail trim are interested in this. I have a set-up guide from a sail maker for my boat but I would like to do my own settings based on some knowledge and symptoms as I am trimming.
First I would go sailing upwind and once settled I would let go of the tiller to see what happens. If the boat slowly turns up the rig is probably close to where I want it to be. If it turns down I want to move the mast head aft by lengthening the forestay and if she turns quickly up I want to move that masthead forward.

Assuming I have pre-bend that looks about right and the sail has sufficient draft I will move on to backstay tensioning. Otherwise if the sail is too deep I will increase tension on the V1's to add pre-bend in the mast and if the sail looks too flat I will soften the D1's to straighten the mast. It is a given that this setting will vary depending on the wind strength.

If the sail looks right at this point I will put on some backstay to flatten the main and to tension the forestay removing sag from it. If the sail will not flatten because the mast won't bend I will soften the V1's and V2's keeping an eye on the shape of the curve. If the sail goes right into overbend wrinkles I will tighten the V1's and V2's to make the mast harder to bend but still allow me to take sag out of the forestay by putting on backstay.

I should have qualified this to say my boat is a fractional rig with swept back spreaders.

Any thoughts on the process/steps?

 

[Davidasailor26]

First I would go sailing upwind and once settled I would let go of the tiller to see what happens.

Rather than letting go of the tiller I’d hold the tiller and measure the rudder angle needed to hold a steady course. A measured number of degrees will be easier to quantify than “quickly” or “slowly”. Also if you let go of the tiller it might just bounce in a wave, and once it turns a little it’ll turn itself more, so that’s a less precise measurement. If you have an autopilot with a display and rudder sensor that can tell you the rudder angle easily. If not you’ll have to eyeball it. The target would be about 2-3 degrees of weatherhelm deflection if I remember right.

 

[dlochner]

The sailmaker's guides are starting, not end points. They don't know how heavy your tool box is or where it is located, how much beer is in the cooler, and many other factors unique to your boat.

Objective data is essential to developing your own tuning guide. Measuring the shroud tension and wind speed, measuring tiller angle, boat speed and so forth. Second is record keeping and experimentation. Use a Loos gauge to measure base tension and how many turns tighter or looser in various conditions. Find a way to measure tiller angle. Etc, etc.

With good records and experience you will begin to dial in the best settings for your boat and the current conditions. The most successful racers I've known and sailed with will tune the rig before the race for expected conditions and re-tune the rig between races.

Data and records are the key.

 

[Will Gilmore]

What type of rig do you have?

Assuming I have pre-bend that looks about right and the sail has sufficient draft I will move on to backstay tensioning.

Depending on your rigging, backstay tension usually determines your pre-bend. So you might not want to change that if you have a typical fractional rig and are happy with sail draft.

-Will

 

[danstanford]

What type of rig do you have?

Depending on your rigging, backstay tension usually determines your pre-bend. So you might not want to change that if you have a typical fractional rig and are happy with sail draft.

-Will

Deck stepped fractional with swept spreaders.
With the swept spreaders the pre-bend comes from the D1's pulling down on the mast tip and spreaders. I will have pre-bend without any backstay at all. Certainly adding backstay adds bend as you suggest,

 

[danstanford]

What type of rig do you have?

Depending on your rigging, backstay tension usually determines your pre-bend. So you might not want to change that if you have a typical fractional rig and are happy with sail draft.

-Will

Will, sorry for the late reply.

I have pre-bend with the backstay right off in my boat. My understanding is that the swept spreaders, when tensioned, push the mast forward.

I will set the pre-bend with V1 tension and then manage the shape of the bend with the D1 and D2 tensions. Application of the backstay will generally bend the upper mast more from the pre-bend state.