CRF (Classic Rating Formula) was developed as a measurement system for rating yachts of varying types and sizes with traditional, full-keeled designs. The CRF was an adaptation and development of the old CCA Rule, adjusted over time for classics – for use in the Opera House Cup, The MOY Classic Yacht Regatta, and the Herreshoff Rendezvous.
However, it wasn’t a single entity issuing ratings. It was used in various forms by different classic races along the East Coast during the 80’s. Every event was using a custom variation of the formula and the same boats would have wildly different ratings from event to event. In the late 80’s an attempt to create a standardized rating system among all events so ratings were consistent, created the WoodenBoat Regatta Series.
The WoodenBoat Regatta Series, and the CRF Ratings were coordinating dates, schedules, and issuing consistent rules and ratings for Classics – meeting annually and agreeing on all rules and adjustments. Only the OHC used their own custom variation during that time while all other events (as many as 12 per season) used the CRF formula. The North American Panerai Classic Yacht Challenge (NAPCYC) took over that role in the 2000s, and managed the coordination of rules and ratings until 2016.
In 2016, the Classic Yacht Owners Association (CYOA) formed a technical committee to review CRF versus other rating alternatives including PHRF, Europe’s CIM, and an ORC VPP-based system. The group quickly recognized that current CRF ratings provide a reasonable reflection of the real world performance potential of some yachts within classes of similar sizes and types. However, the Committee also recognized that there were notable exceptions, and as a means of addressing those shortcomings, the Committee developed a comprehensive reformulation of CRF that was dubbed ‘CRF MkII’. The formulae underlying the MkII proposal were based on the CRF 2016 data requirements. Starting in 2020, the CRF will be referred to by year of issue (CRF 2020.)
A CRF rating continues to be based on owner-supplied measurement inputs and no subjective adjustments are made to the calculated ratings. A CRF rating is expressed on the certificate both in decimal feet and in seconds per mile. The formulae and factors on which the CRF rating calculations depend are refined annually based on a quantitative analysis of race results from previous seasons, so ratings often change slightly from one year to the next. CRF is committed to full transparency, so all valid certificates and the calculations on which the ratings are based are available for inspection on line.
CRF 2020 Technical Committee
- Simon Davidson, Chair
- Adam Langerman
- Joe Loughborough
- Brad Read
- Bob Stephens
- Greg Stewart
- Jim Taylor
- Susan Wayne
- Steve White
CRF Background, Formulae, and Factors
The Classic Rating Formula (CRF) was first developed in the 1980’s to encourage participation in classic yacht racing by providing a rating system that was tailored to suit the unique characteristics of those boats. After decades of both increasing interest and resulting pressure on the ratings that were produced, a newly formed Classic Yacht Owners Association (CYOA) recognized that it was time to take a fresh look at the details of the system used. A technical committee was formed not only to evaluate CRF as it was, but also to consider alternatives such as Europe’s CIM, PHRF, and even a sophisticated VPP based system. In the end, the committee decided that the best approach would be to fundamentally rework CRF, and the result of this effort, then dubbed CRF MkII, debuted at the start of the 2017 classic racing season.
The current version of CRF maintains continuity with its original form by keeping a similarly firm focus on providing fair racing for classic yachts, and by keeping it ‘user friendly’ by embracing the use of owner declared data rather than requiring official measurers. Most (but not quite all) of the required data declarations for CRF now are the same as those needed by its original form, the ratings of most boats relative to others in the classic fleet have remained similar.
Going forward, the primary goals of CRF are to refine the rating formulae annually, based on careful quantitative analysis of race results after each season, and to maintain full transparency in the way the ratings are generated. All of the formulae and factors used in calculating a CRF rating are published on- line (see below), and there are no subjective adjustments made to ratings. It is a straightforward ‘data in and ratings out’ calculation for all boats, and the only human involvement in the process is a review of the data declared on-line to assure that it reasonably reflects the characteristics of the boat as she will be presented on the starting line.
For those without the time or inclination to wade through the published factors and formulae, the following short summary of how ratings are calculated may be helpful:
- A ‘base rating’ is calculated first. Its most important initial term carries the performance drivers of effective sailing length ‘L’ and the square root of rated sail area ‘S’ in the numerator, and the performance limiter of displacement ‘DSPS’ in the denominator, much as in Nathaniel Herreshoff’s Universal Rule did in the early 1900’s and IOR 60 did years later. The calculations for effective sail area include factors for rig type (sloop, yawl, etc.) and for standing rigging material. This first term is then adjusted by a Draft Correction ‘DC’, a Length/Beam Ratio Correction ‘LBRC’, and a Stability Correction ‘StabC’.
- The final rating is calculated by applying Propeller, Displacement/Length, Sail Area/Displacement, Keel Type, Spar Material, and Moveable Appendage factors to the base rating.
The current formulae and factors used in calculating CRF ratings will be published soon.
Frequently Asked Questions
Q. I’ve noticed that on my certificate I have a CYOA Division listed, but that division is not always the one that I compete under. Sometimes, I compete against a group of yachts, but at another regatta, I’m in a different division. Why is that?
A. Divisions are provided as guidelines to Organizing Authorities; each regatta may, based on their individual traditions or due to a lack of entrants, place competitors in different divisions, so you may not compete against the same yachts from event to event.
Q. My new rating is different than it was last year, but my data declarations are the same. Why? What caused the rating change?
A. The formulae and factors used to calculate ratings are routinely refined annually, based on a quantitative analysis of race results from the previous season, so ratings often change from one year to the next.
Q. I have had a valid CRF certificate in the past, and wish to renew for this year. Is there additional information that will be required?
A. The online application/revalidation process for acquiring a CRF certificate is quite straightforward, with pop-up help available for data definitions. Most of the information required is the same from year to year, and it is resident on the site under your online CRF account. You should check all of your declarations to be sure that they accurately reflect the way that you intend to race your boat this year, but you will not have to re-enter them if they have not changed. Occasionally some new data will be required that has not been included in previous years.
For CRF 2020, the following additional information will be required:
– Standing rigging material, if not provided previously. This was requested in 2019 but not used in calculating ratings. It will be required in 2020, and will be used in calculating 2020 ratings.
– Stern type for canoe sterns (double enders) only.
– Mainsail and spinnaker girths (luff to leech widths). This data is being gathered for rule development testing in 2020, but will likely be used in calculating ratings in 2021.
– Design and build year (to help with division assignment)
A. Certificates of all currently registered classic yachts may be viewed by going to the CERTIFICATES CRF Database.
Q. I believe the rating on a competitor’s yacht is wrong. How can I confirm if the rating is accurate?
A . A first step should be to check the declared data on which the rating is based. CRF is committed to full transparency, and all valid CRF certificates are available for inspection online. If you still have questions, you can file a rating inquiry.
The CRF Technical Committee will review the certificate, and if there is a error, they will notify the yacht owner of the error and any resulting change in rating. IF the measurement in question needs verification from an independent outside source, a measurer will be hired at the expense of the appealing party.
A. First, while it is possible that an input error has been made, be aware that the formulae and factors used to calculate ratings are routinely refined each year, so ratings often change from one year to the next. For example, for 2020, a Standing Rigging factor will effect ratings compared to 2019, as will an improved Stability Correction.
Also 2020 ratings reflect an adjustment to the effective sailing length of canoe stern (double ended) hulls. Of course, it is also possible that an error in data input has been made. If you feel that this is the case, file an inquiry. The CRF Tech Committee will review if there is an error. If so they will notify you, correct the rating, and reissue you a new certificate.
Q. I’ve made a mistake on measurements on my application, and my certificate has been issued. What do I do?
A. File an inquiry and see our process here. Your request will be reviewed by CRF handicappers, and if there is an error, they will notify you, make the change in the data, and reissue your rating with the corrected measurements.
Q. Can I have more than one CRF certificate with different data declarations (e.g. different sail configurations) that are valid for racing at the same time?
A. No. A boat will be allowed one configuration change only during any one season. A new CRF certificate reflecting that one change must be issued at least 10 days before the next race in which the boat competes, and the boat may not revert back to her original configuration later in the same season. (This ‘one change’ limitation does not preclude correcting errors or making minor updates to declarations, which may be accepted and a new certificate issued, at the discretion of CRF administration).
A. A CRF certificate is valid for the calendar year in which it is issued, and must be renewed each year.
A. Once processed,
A. Although the application is processed automatically for a rating, to ensure accuracy each certificate will be manually reviewed before it is issued. Plan on at least 5-7 business days, and if applying during July and August, it may take longer due to a larger number of certificates being issued.
A. A certificate costs $50.00. The fee contributes to the expenses of rating rule administration and development.
Hull and Underbody Questions
Q. Where/How do I find the weight of my keel so I can complete the ballast weight portion of the certificate?
A. Designer data, builder specifications and brochures, etc. are typically the best source. If necessary, the CRF Technical Committee can help with researching ballast data or even calculating it from measurements.
To request help in calculating your ballast weight, complete as much of your CRF Application as you can, use our Data Inquiry Form to request help and specifically request assistance in determining your ballast weight.
Q. I have a yacht with a centerboard, and none of the keel profile sketches displayed in the rating application show a centerboard. What keel type should I declare?
A. Check the box corresponding to the underbody profile that most closely resembles the fixed portion of your keel. CRF accounts for the effect of the centerboard via the declared value for ‘Draft Centerboard Down’.
A. Stability and wetted area are critically important performance parameters, but it is not reasonable or practical to ask owners to declare appropriate values for them. The 6 underbody types displayed on the CRF rating application work as surrogates for stability (via related keel volume, VCB and VCG), and for wetted area more directly. In addition, the various underbody type options help account for the advantages of a high aspect ratio fin with separated spade rudder over a lower aspect ratio configurations, including a full keel with an attached rudder.
Q. I have determined that the displacement of my yacht is heavier than that shown in the designer/builder specifications. How does this affect the other CRF data declarations that I need to make?
A. If you are declaring a displacement that is heavier than the designer/builder specification, it follows that your declaration for the LWL that corresponds to that heavier displacement should be longer, and that your declaration for Draft should be deeper, than the designer/builder specified values. One way to quantify the differences in LWL and Draft (DM) would be to estimate the sinkage resulting from the difference between the designer/builder spec and the declared displacement (DSPS). The ‘Pounds per Inch Immersion’ (sink) for most boats can be approximated by: Lbs/in Immer = 1.1*LWL^2. It follows that actual sinkage (in inches) = delta DSPS/Lbs per In Immer. This estimated sinkage would equal to the amount added to the designer/builder specified Draft (DM) in inches , and for most boats multiplying this sinkage by 6 approximates the amount added to the designer/builder specified LWL, also in inches.
Q. The only information that I have on displacement for my yacht comes from original design specification. How can I update that to a current ‘as raced’ weight?
A. Designers and builders typically provide displacement data referenced to the ‘design waterline’ that most often resembles a ‘light ship’ condition, with empty tanks and minimal food and gear. The weight added in equipping and provisioning for coastal cruising can increase that displacement by 10%. The boat hauling equipment in some yards can provide a boat weight, but these weights are typically not especially accurate, and should be used as a rough reality check only.
Rig and Sail Questions
Q. Explain the 2020 requests for sail girths (widths) for mainsails and spinnakers is new for 2020.
A. Requests for sail girths (widths) for mainsails and spinnakers is new for 2020, and they were intended to be for newly built sails only, as the data would be readily available to owners from the sailmaker. These sail girths are just used for data gathering and not for ratings in 2020, and an apology is due to owners for not implementing the ‘new sails only’ part of this request as intended. The intent is to include mainsail girths in ‘CRF 2021’ sail area calculations for newly built sails to reflect the fact that modern sailmaking methods and materials can support roach profiles that are substantially more aggressive than those that are typical of the existing Classic fleet, and this has given those new sails extra area that has been ‘free’ in terms of rating. Similarly, in the interest of simplicity, CRF has been calculating a downwind sail area that includes an assumed spinnaker area that is a function of the height of the chute halyard and the length of the pole and/or spinnaker tack point. To head off teams gaining an unrated advantage by building spinnakers with girths that are larger than those that typical of the Classic fleet, for ‘CRF 2021’ the area for newly built spinnakers will likely include their measured, rather than an assumed, mid width.
A. Sail material guidelines are intended to encourage the use of sails that are cost efficient and that are aesthetically appropriate for Classic racing. The 2020 recommendations remove the prior requirement for paneled construction and allow for ‘molded’ sails. This change also removes the requirement for ‘woven fabric.’ Carbon is prohibited since low stretch sails risk damaging older hulls hardware, and rigs. Only classic, light colored sails are allowed.
A. The rigs of some older boats have been upgraded by replacing the original wire standing rigging with stainless steel rod, which implies a rating advantage. Also, some boats are fitted with composite (typically carbon) standing rigging, that results in a substantial performance advantage. A Standing Rigging Factor that is new for CRF 2020 addresses this advantage via a rating adjustment.
A. Yes, as long as you declare a spinnaker pole length ‘SPL’. Note that a whisker pole can only be used to wing out a headsail, and not to trim a spinnaker. Also, be aware that if you do declare an ‘SPL’, your calculated spinnaker area will be larger, and your rating will be
A. Yes, as long as you declare a spinnaker pole length ‘SPL’. If you declare both a pole length ‘SPL’ and a spinnaker tack point ‘TPS’, CRF will calculate a spinnaker area for both an s-sail via SPL, and an a-sail via TPS, and it will calculate rating on whichever area is larger.
A. Any pole used in trimming a spinnaker is a spinnaker pole, and it is rated as such with its overall length declared as ‘SPL’. A whisker pole is a pole used to wing out headsails only, and its length is limited to not more than 1.1*’J’. A spinnaker pole with a declared length not longer than 1.1*’J’ can be used as a whisker pole to trim headsails. A boat can use a spinnaker pole with either symmetrical or asymmetrical spinnakers, but if a spinnaker pole is declared, the boat will be rated for an s-sail spinnaker area, whether or not she actually carries any s-sails.
Q. Can you explain the definition and use of the declaration for the tack point of an asymmetrical spinnaker (TPS)?
A. ‘TPS’ is the distance from the forward face of the mast to the attachment point for an a-sail tack to the deck, to an anchor roller, to a bowsprit, or to a similar fixture. If an a-sail is tacked to the stem near the headstay tang, ‘TPS’ is nearly equal to ‘J’, the length of the foretriangle base. If an a-sail is tacked further forward to the end of an overhanging stem or to a bowsprit, ‘TPS’ will be significantly larger than ‘J’, the rated area of that a-sail will be bigger, and the rating will be faster. Under CRF MkII the change in rating for increasing ‘TPS’ is generally in line with that of other handicapping systems.
Q. In light air, I plan to fly a headsail whose mid girth is less than 75% of its foot length, but it is too big to fit inside the nominal foretriangle. What should my declarations be for foretriangle height (IG), foretriangle base (J), and longest perpendicular, LP?
A. This sail is by definition a headsail and not a spinnaker (See RRS 50.4), and CRF will rate it as a headsail. For such a sail, ‘IG’ would be declared as the vertical distance from the sheerline to the top of the sheave supporting its halyard, and not to the upper end of the nominal foretriangle headstay. Similarly, for such a sail, ‘J’ would be declared as the horizontal distance from the forward face of the mast to the attachment point for its tack on the deck or bowsprit, and not to the nominal forestay headstay tang at the deck. And finally, the LP of this sail would be the distance from its clew to its luff, measured perpendicular to the luff, and not the LP of a smaller sail set in the nominal foretriangle. Note that CRF will rate the speed potential of the boat with this sail in its best condition, and that the rating with such a sail will be ‘faster’ than it would be with a smaller headsail set in the nominal foretriangle, even when only that smaller sail is flown. Note further that some race organizers will require that such a headsail must have its luff attached to a stay, and that it cannot be set free flying
A. A spinnaker is any sail set forward of the foremost mast whose width, measured between the midpoints of its luff and leech, is equal to or greater than 75% of its foot length. (See RRS 50.4)
Q. Some previously ‘square head’ mainsails in the Spirit of Tradition (SOT) class were converted to gaff headed sails and were rated as such in 2016. How will such conversions be dealt with under CRF?
A. Under CRF, gaff headed mainsails in the SOT class will be rated as ‘square headed’. Exceptions to this approach are possible in cases where the sail configuration is very intentionally designed to have an entirely traditional appearance, with the gaff length on the order of 2/3 that of the boom length. However, any such exceptions shall only be made after special consideration by, and at the discretion of, the rating authority.
Q. Can you clarify the difference between the declared heights of jib headed and gaff headed mainsails?
A. The height of a jib headed mainsail is declared as ‘P’, which is essentially the luff length of the sail. The height of a gaff headed mainsail is declared as ‘PG’, which is the height from the mainsail tack to either the peak halyard block, or to head of a topsail (if carried), whichever is higher.