ORC Double Handed Certificate
   
 
 

An ORC Double Handed certificate is comprised of two pages, and can be translated into any language. These are issued by rating offices for boats with existing ORC Club or ORC International certificates that want to race in a Double Handed format, so the default crew weight is fixed at 170 kg. Sails on an ORC DH certificate may be any combination of what is in the Sails Inventory of the full-crewed certificate.

The first page of an ORC DH certificate resembles an ORC Club certificate, with a proportionally-scaled boat drawing shown with measurements of the sails, rig, hull, and other measurement details.
 

 

 

 
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  ORC DH certificates will be branded as Club or International, depending on the quality of the measurement inputs in the original full-crew certificate.  A key difference from the Club certificate is the Scoring Options box, which contains Time on Time and Time on Distance ratings for four course model types that are common for distance races: Coastal/Long distance, Circular Random, Predominantly Upwind and Predominantly Downwind courses.

The second page is a polar diagram showing the performance of the boat through a range of conditions…these are also available in an ORC Speed Guide that may be generated for the boat in Double Handed trim.

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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POLAR DIAGRAM
Polar diagrams plot the performance of the boat predicted in knots of boat speed on the radial coordinates and Apparent (left) and True (right) wind angles in the angular coordinates for 6, 8, 10, 12, 14, 16 and 20 knots of true wind speed. The colors in the plots correspond to sails listed on the certificate being used to calculate the boats speed in each of these wind strengths.
BOAT
Boat's name and sail number issued by the relevant National Sailing Authority.
GPH

GPH is General Purpose Handicap. It is an average representation of all time allowances used for very 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.
CLASS

Class 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.
COMMENTS
This space is used by Rating Officers for comments on particular certificate.
PROPELLER

Propeller data includes type of propeller (solid, folding or feathering) and propeller installation (in aperture, strut drive or shaft) followed by propeller diameter PRD, propeller blade width PBW and propeller installation projected area PIPA.
HULL

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.
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.
CENTERBOARD

Centerboard is measured separately from the offset files with set of measurements defining its size and moving range.   

SCORING OPTIONS

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.
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
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 GPH. 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.
Stability

Limit of positive stability as measured or estimated is shown together with Stability Index and appropriate Category of races according to the Offshore Special Regulations for which boat is eligible.
Owner

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