IRC Jargon Translated

All rating rules contain acronyms and abbreviations, although IRC less complex than most, with minimal inputs.  This page does not replace the IRC definitions which are part of the full Rule text, but is a quick guide.

Hull

  • LH: Hull Length (note that sales brochure Length Overall sometimes includes pulpit/bow roller, not included in LH)
  • LWP: Waterline length
  • BO: Bow overhang
  • SO: Stern overhang
  • y, h, x: Additional measurements taken at the bow and stern
  • DLR: Displacement/Length Ratio

Rig

  • P: maximum hoist point of mainsail (on mast)
  • E: maximum outhaul point of the mainsail (on boom)
  • J: from the mast to the forestay attachment point
  • FL: Forestay length
  • STL: Spinnaker tack length

Mizzen rig

  • PY: maximum hoist point of mainsail (on mizzen mast)
  • EY: maximum outhaul point of the mainsail (on mizzen boom)

Mainsail

  • MUW: Mainsail upper (7/8) width (ie. taken 7/8 of the way up the leech)
  • MTW: Mainsail three quarter width (ie. taken 3/4 of the way up the leech)
  • MHW: Mainsail half width (ie. taken 1/2 way up the leech)

Headsail

  • HLUmax: Maximum luff length on any headsail
  • HLU: Luff length of largest headsail
  • HLP: Luff perpendicular – from clew to luff
  • HHW: Headsail half width (ie. taken 1/2 way up the leech)
  • HTW: Headsail three quarter width (ie. taken 3/4 of the way up the leech)
  • HUW: Headsail 7/8 width (ie. taken 7/8 of the way up the leech)
  • HSA: Headsail area

Spinnaker

  • SLU: Spinnaker luff length
  • SLE: Spinnaker leech length
  • SFL: Spinnaker foot length
  • SHW: Spinnaker half width (half luff to half leech)
  • SPA: Spinnaker area

Mizzen staysail

  • LLY: Luff length
  • LPY: Luff perpendicular

Stability and safety

  • STIX: Stability Index
  • AVS: Angle of Vanishing Stability
  • SSS: Safety & Stability System
  • ISO: International Organization for Standardization
  • OSR: Offshore Special Regulations published by World Sailing