MultiRule has transitioned to ORCmultihull (ORCmh)

ORCmh is now issuing certificates

The background story behind "OMA MultiRule" and it's Goals

April 2017

The goal of the MultiRule is to allow a range of multihulls, 40 ft and larger, to race as fairly as possible in all wind conditions. The intent is that the best crewed boat in a particular race finishes with the lowest corrected time.  A guiding principle is that the MultiRule is trying to mimic one design racing (crew performance, not boat design, determines corrected results.) The MultiRule is not intended to be a “golf handicap” or a subjective PHRF type approach.  

The operation of the MutliRule will be transparent.  The analyses which determine and refine polar curves, the methods of determining boat weights and other particulars, and the inputs to and methods of PCS scoring will be transparent to all competitors. The owners of the racing boats will govern the MultiRule through the MultiHull Owners Association (“OMA”).


Ratings Goals Include

  • To rate each boat based upon accurate polar curves 
  • Initial polars for a boat will necessarily be VPP based or adjustments to known design based (as determined by a VPP analysis firm) 
  • Subsequent event polars will be refined from VPP polars based upon prior events’ instrument data analyzed by VPP analysis firm
  • Sampling and/or other methods will be used to discern fastest potential speeds and minimize the effects of crew skill
  • Human judgement/observations/opinions (aside from VPP analysis firm) will not determine polars
  • The MultiRule will define and refine methods for determining boat weights prior to events
  • Boats will be provided post event log based polar curve analysis so that all competitors understand reasons for polar curve adjustments


Scoring Goals Include

  • To score races using a version of the PCS scoring system 
  • To accurately measure, by leg, the course wind conditions, which are inputs to PCS scoring
  • To accurately measure the course itself and accurately weight each point of sail, which are inputs to PCS scoring


Conduct Goals Include

  • Prior to an event each boat’s declared sails, crew weight, boat weight and possibly other attributes will be determined.  These boat attributes cannot be modified without permission
  • Any structural boat modifications which affect a boat’s speed (e.g. new spars, blades, rigging, types of sails, etc) will be declared promptly so that polars can be initially modified before the next event occurs
  • A participating boat must have sufficient and reliable instrumentation such that the required data can be collected for refinement of its polars
  • OMA may set out safety rules in cases concerning boat modifications which improve performance/scoring under MultiRule but are deemed “unsafe”

KND SailingPerformance MultiRule:

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