ORC International Certificate


ORC International certificate comes in two A4 pages with optional third page. First page contains all the rating details used mainly by the race committee to score races as well as by sailors while racing.

Second page is the IMS Measurement certificate that includes all the measurements of rig, sails, propeller, freeboards and inclining test. Optional third page is showing sail plan and complete sails inventory.




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


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Boat's name and sail number issued by the relevant National Sailing Authority.

GPH is General Purpose Handicap. It is an average representation of all time allowances used for basic comparisons between boats for determining possible class divisions.

It is calculated as an average of the time allowances of 8 and 12 knots true wind speed for the Circular Random pre-selected course.


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

Name and date of the Offset file describes the file used for the complete hull shape definition including keel and rudder. It is not accessible except by the designer and the rating office.

Name of the measurer and the measurement date is also recorded.


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

IMS Division (Performance or Cruiser/Racer) is defined by IMS Appendix 1 where Cruiser/Racers are boats designed for cruising and are equipped with accommodation layouts at least comparable to the standards of series production boats. Boats not meeting these requirements are categorized in the Performance division.

Dynamic Allowance is a rating credit representing the dynamic behavior of a boat taking into account performance in unsteady states (i.e., in heavy seas or while tacking). Additional hull information includes: Forward Accommodation, as the type of interior volume forward of the mast, and Hull and Rudder Construction type.
Crew Arm Extension is a factor taking into account the possibility of extending the crew position beyond the sheerline, such as seen on Sportboats in accordance with Sportboat Class rule 4(c).
The main hydrostatic values are given here, such as IMS L - an effective sailing length which takes in account hull shape along its length, RL - Rated length used for Class Division Length (CDL) calculation, VCG - vertical centre of gravity from the offset file datum (VCGD) or from measurement waterline (VCGM). Sink shows how much weight change is needed to change the draft 1 mm, while Wetted Surface (WS) is given as one of the main factors in hull resistance.

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. 

Velocity Prediction in Knots for True Wind Speeds
Time Allowances set above are easily converted to boats' predicted wind speeds in knots 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.
Rating Office

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.

For countries where a National Rating Office is not yet established, the central ORC Rating office can give support by issuing certificates.


Certificate number is used for the ORC Rating Office administration, while 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.

Crew Weight

Crew weight, 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 may have a Declared value specified by the owner, but if not declared a Default figure is calculated and listed on the certificate.

The crew shall not be heavier than the Maximum value recorded on the certificate. And if the Notice of Race or Sailing Instructions specify, then the crew weight shall not be less than the Minimum shown on the certificate.

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.

Sails Limitations

The maximum number of sails allowed on board while racing according to the CDL. Headsails include those set on the forestay and headsails set flying. Spinnakers include: symmetric and asymmetric.

As only one mainsail is allowed regardless of a boat's rating, it is not listed here.

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.


Owner's name and address with statement to be signed: "I certify that I understand my responsibilities under ORC Rules and Regulations"