Backstay tension

Samuel thanks for clarifying the 1.5 bend thing in my message. 

I just point out that early masts were pretty round/oval shapes, and then along came the Delta sections which were stiffer in the athwart ship direction than the fore and aft direction, making them widely used for bendy mast fractional rigs. Any riggers on forum or mast stress men, maybe like to comment on this aspect?

I'm still happy with my 1.5 times the fore and aft dimention of section as max bend. I have used differential drum winches and cascaded back stay tackles to acceive my bend, but I always mark the system at my max pre-bend limit. Measured from Main haliyard straight line on a wind free day.

 I should buy a suitable tension gauge to check things all round the rig, but never got round to it. Would anyone who has this tension data please show the data?

You got it Richard,

I have loved sailing fractional rigs for these reasons. 

Your biggest sail you have greatest control from full deep draft with clew outhaul loosened main halyard slack, main twisted off to deal with low speed wind vectors as you go up in height.  Thru to main flattened out clew outhaul tightened halyard tightened pulling draft forward, or first reef in,  mast bend applied taking the top of sail to flattened shallow draft [fast shaped] and still powering upwind.  Forestay tighten to keep foresail aerodynamic  rather than bag of wind you see on a typical mast head rig part rolled genoa.

Sorry to be geeky, I get a touch religious about my fractional rigs!!!

PS  1.5 diameters, is just my go to number. When a well cut main is fully flattend [my friends say "bladed out"] there is ittle point in further bend.

Perry