ORC Multihull Certificate

  ORC Multihull certificates come in four A4 pages. The first page gives a general overview of the boat with its rated boat speeds, in addition to the measurements of the main hull, the propeller, the rigging and the sail.

The second page is presenting the scoring options.
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The third page is showing a detailed list of measurements of the hull and appendages, propeller, rig, flotation, and the measurement inventory, while the fourth page is reserved for measurements within the sails inventory. 

Place the cursor over different parts of the certificate page for a brief explanation. More details are given in the measurement and scoring sections, while complete definitions can be found in the appropriate rules documents.


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This is a space for the Rating Office logo. ORC Rating Offices are established worldwide in each country that has active offshore racing. Rating offices have several functions, including supervising the measurement and rating of yachts, supporting ORC racing by administering to their national fleets, and issuing ORC certificates.

Currently, ORC Multihull certificates are issued by the ORC Central Rating Office while this role will be given to the National Rating offices in the future.


MHR is Multihull Rating. It is an average representation of all time allowances used for basic comparisons between boats for determining possible class divisions. It is also used as a single-number Time on Distance scoring co-efficient for the All-purpose course type

It is also used as a single-numaber Time on Distance ecoring co-efficient for the All-purpose course type.

Boat description data includes Class, Designer and Builder as well as Age and Series Dates

Age Date is the month and year of the first launching, while Series Date is the Age Date of the earliest boat of an unmodified series built in production moulds or jigs.

Offset file describes the file used for the complete hull and appendages shape definition.

Hull data includes the boat's primary characteristics while in measurement trim: Length overall, Maximum Beam, Draft and Displacement

Age Allowance is a rating credit for age increasing each year up to a maximum of 15 years.

Propeller data includes propeller installation (in aperture, strut drive or shaft) and type of propeller (solid, folding or feathering) followed by propeller diameter.


CREW, an important factor affecting the boat's performance, is considered in the VPP rating calculations.

The weight of all crew members on board while racing weighed in light street clothes shall not be greater than the 130% and smaller than 85% of the number recorded in the certificate.

Crew Arm Extension is a factor taking into account the possibility of extending the crew position beyond the sheerline.

Measured rated sail areas are shown for the largest sails of each type recorded: mainsail, hesadsail set on the forestay, headsail set flying as well as symmetric and asymmetric spinnakers.


Owner's name and address with statement to certify that he/she understand his/her responsibilities under ORC Rules and Regulations.

Proportional scaled boat drawing with main rig and sail measurements which may include some items depending on the actual rig and sail configuration as follows:
  • The rig configuration details vary with the input. Thus, the spreaders diagrammed match the spreader count, the standing rigging matches adjustable stays recorded, an inner forestay is shown if recorded and split rigs are shown with a mizzen together with appropriate dimensions.
  • A bow sprit is shown if the headsail or asymmetric spinnaker can be tacked forward of the stem.
  • The transom geometry will represent the actual boat's transom in various types that vary from the default reverse transom to options that have an outboard rudder.
  • Asymmetrical spinnakers are shown according to the type declared for the yacht; i.e., the type which the rule requires to be tacked on the yacht’s centerline (with no pole aboard) or else an asymmetrical which may be tacked on a spinnaker pole.
  • Measured sail areas are printed for the largest of each sail type.
  • A cruising-type main with in-mast furler/reefer and/or a headsail furler/reefer is displayed if fitted.
As a result of VPP calculations predicted boat velocites for wind speeds in knots ar given for a complete set of polar plot for different wind conditions in the range of 6 – 20 knots of true wind speed from optimum beat, over 52, 60, 75, 90, 110, 120, 135, 150 degrees of true wind angle to the optimum run.
These predicted speeds can be easily used on boat for comparison with real performance and as it also shows Beat and Run VMGs with appropriate angles.

ORC Reference number is a unique number identifying that certificate and may be retrieved in the ORC database available at the ORC Sailor Services.

There is an issue date as well as a VPP version used together with the latest date for the validity of the certificate.  

A boat shall have only one valid certificate at any one time. The valid certificate is the last one issued.

ORC Certificates are valid for one year. This is because the VPP software calculations are updated yearly based on the ITC’s latest research of aero and hydrodynamics, as well as improvements made from analysis of race results and boat performance during the racing season, and submissions made from ORC Nominating Bodies.


One of main advantages of the ORC Rating Systems is variety of scoring options which can be selected locally based on expected wind conditions, type of racing or fleet composition.

Simple scoring options includes: Time On Distance and Time on Time as well as Triple number, set of three different Time On Distance or Time On Time coefficients for different wind strengths.

All scoring coefficients are given for Windward / Leeward races (50% beat, 50% run) and Coastal / Long Distance races (Different percantages of beat, reach and run).

Scoring options are explained in more details in Scoring section.

An ORC International certificate provide a range of ratings, expressed as Time Allowances in s/NM for different wind conditions in the range of 6 – 20 knots of true wind speed for an optimum beat, and for 52, 60, 75, 90, 110, 120, 135, 150 degrees of true wind angle for an optimum run.
These time allowances are used in Performance Curve Scoring as a unique feature that is fundamentally different and much more precise than any other handicap system. It can rate different boats for different race conditions and course configurations by giving the boat’s theoretical predicted speeds for any wind condition and direction.

Scoring options are explained in more detail in the Scoring section.

Selected Courses
Four types of Pre-Selected courses are calculated from Time Allowances above:
Windward/Leeward (up and down) is a conventional course around windward and leeward marks where the race course consists of 50% upwind and 50% downwind legs.
Circular Random is a hypothetical course type in which the boat circumnavigates a circular island with the true wind direction held constant. 

Ocean for PCS is a composite course, the content of which varies from 45% Beat VMG and 55% Run VMG at the 6 knots with decrease of Beat and Run parts and increase of reaching parts with increase of the wind speeds;

Non Spinnaker is a circular random course type (see above) but calculated without the use of a spinnaker or any headsail set flying. 

Special Scoring

Special scoring options are available in Time on Distance and Time on Time coefficients for Double Handed and Non-Spinnaker configurations.

Double handed ratings are calculated for a crew weight of 170 kg, and Non-Spinnaker ratings are shown for offshore races for which Performance Line coefficients are also given.

Double handed ratings are shown on the certificate when this option is selected by the Rating Office. The Rating Office may also produce a separate Double handed certificate where differences can be found in rig and sail measurements, not just crew weight, for the same boat.

Scoring options are explained in more detail in the Scoring section.

Class Division Length

Class Division Length (CDL) is the average of the effective sailing length (IMS L) and the rated length (RL) that is calculated from the upwind speed of the boat in a True Wind Speed of 12 knots. It is used for class divisions as a combination of the boat’s upwind speed and length.

Storm Sails Area

Maximum area for storm sails as required by the WS Offshore Special Regulations: Heavy Weather Jib, Storm Jib and Storm Trysail.