Hi, I am defining a sail geometry using the SailModelfile.js and the sail topology parameters. Just to be sure and precise, are the length data measurement corresponding to straight lines measures or curvilinear measures?

In other words, is LFoot the straight line dimension from tack to clew, or the actual developed (curvilinear) length of the foot edge of the sail? Same question for LLuff.

Also, how is defined the position where to measure r25 r50 r100? Is it:

  • r25 is the positioned as the line cutting through the points on 25% of the luff and leech?
  • r25 is the positioned as the line cutting through 25% along either luff or leech and is parallel to the foot or head?
  • PS: these definition are equivalent or close when having a triangle or close to triangle shape, but may results in some differences when considering a more squared shape (r100 >> 0) such as for a squared head mainsail.
  • Once the position is defined,  is the r25 ratio numerator (r25*LFoot) using the direct straight line measure from point on luff to point on leech at that stripe location, or the developed curvilinear dimension (developed) at that stripe location?

Thank you.

Support SumToZero Answered question 14 May 2024