The following article appeared in the December 2008 issue of Australian Sailing, Australia's monthly sailing magazine, on ORC International's introduction to Australia. Authored by Features Editor Bob Ross, the article explains how the Cruising YC of Australia initiated the look into having a transparent VPP-based rating rule for use in its offshore events, how ORCi differs from IMS, how the rule works in practice, and the enthusiasm with which noted Australian yachtsman Syd Fischer has also endorsed this new look towards ORCi for the country's handicap rating needs.

New rule for Hobart?

The new ORC International Rule is to be trialed in Australian offshore racing, by Bob Ross

Cruising Yacht Club of Australia is looking seriously at introducing a new handicap rating rule for “grand prix” boats in its Rolex Sydney-Hobart race and other events.

The rule is ORC International, introduced in January this year by the Offshore Racing Congress to replace its International Measurement System rating rule, which the CYCA used for a decade as its grand prix rule.

At the invitation of CYCA Commodore Matt Allen and Vice Commodore Garry Linacre, ORC technical consultant Dobbs Davis traveled to Sydney from the USA to give a presentation on the rule to a meeting of yacht owners.

Sydney yacht designer David Lyons, who is a member of the ORC’s international technical committee, supported the presentation with details about the aero and hydrodynamic modeling efforts to improve the ORC’s velocity prediction program, on which the rule is based.

The ORC reported later: “During a lengthy question and answer period there were many questions raised about how the rule treats various types of boats, what the measurement procedure would be to obtain certificates, how popular it is in use around the world and about the transparent aspects of the rule.

“There is a strong interest among these Australian sailors for a modern handicap rule which is fair and produces predictable rating results, according to CYCA Commodore Allen.”


IMS dropped

The CYCA dropped IMS handicapping in favour of International Rule Club in 2004 when IRC was rising in popularity while IMS was declining. “IMS was encouraging boats to be too slow, too deep and heavy. And the post-construction of courses (for varying wind conditions) became too complicated,” says Commodore Allen.

But the CYCA at that time also recognised the shortcomings of IRC. as a rule for grand prix racing. Announcing the change in February 2004, Rear Commodore Roger Hickman said: “Whilst the IRC rule has now gained international recognition through the International Sailing Federation, it was not designed as a rating rule for grand prix boats and is not an open and transparent rating system.”

He said the CYCA did not see IRC as a long-term replacement for IMS and would apply the IRC rule on a year-by-year basis until a suitable alternative was identified.

That alternative may have arrived. Commodore Allen says that the club will trial ORC International in its racing some time within the next 12 months, once measuring equipment and procedures are in place, but probably not in time for this year’s Hobart race.

“The club’s attitude has always been very clear,” said Commodore Allen. “We are open-minded to the degree that if we get more boats to sail under a different handicap rule we will run parallel divisions. Owners will be able to race IRC or ORCi.

“Everything I have seen in the rule looks good. There are minor issues, like electric winches not being allowed, although there could be flexibility there.

“We are very open-minded. Ultimately it’s the owners’ prerogative to decide which rule they want to race under. It should not be Yachting Australia or the CYCA’s.

”There is probably enough momentum to look at a new rule now where two years ago there wasn’t. There is a sufficient amount of enthusiasm to trial the rule pretty quickly, but I’m not sure there’s enough time to do it for Hobart.”


Syd’s crusade

Offshore veteran Syd Fischer, who has been a stern critic of the IRC over the past three years, strongly supports the introduction of ORC International. With Yachting NSW technical officer John Anderson, has been sourcing the best total surface laser machine for measuring the yachts.

He says he will build yet another new <I>Ragamuffin<P> if the rule is adopted and had only purchased his current boat, a second-hand TP52, because of his doubts about how IRC would treat a new boat.

Fischer says there has been general dissatisfaction with the IRC rule, which is administered by England’s Royal Ocean Racing Club. “My problem with the IRC rules is there is no direct way for an owner to challenge any anomally,” he said.

“We need a rating system that is fair to all types of boats, that will be totally transparent, objective, non-biased, simple to use and understand and not too expensive. Also, the ORCI rating system has an age allowance, which would help the older yachts to be competitive.

“The IRC is an excellent club racing rule Ń that’s what it was originally framed for Ń but it’s not a grand prix racing rule with one man in the world having the say on what your rating is. There appears to be no direct way for owners to challenge the anomalies they believe are in the rating of their yacht, except through the RORC rating office.

“Mike Irwin [the RORC rating office’s technical director] gave a lecture in Sydney and admitted when I questioned him that the IRC is simply a club rule and should not be used for grand prix racing. Why should people with billions of dollars worth of yachts have this club rule foisted on them.”

Two years ago Fischer was a prime mover in a group that formed the Offshore Yacht Owners’ Association to present a strong collective voice.

He says OYOA had pursued the use of the RORC’s IRM fully-measured rating system, had about 20 yachts measured under IRM and in conjunction with the CYCA had been comparing results in long races. But the RORC had abandoned IRM when it became aware of OYOA’s intense interest in it.

“Fortuitously, the ORCI then came out,” said Fischer. “It is a fully transparent system of measurement. It uses the VPP data from the IMS rule for calculating the speed of the yacht through the water at various angles. However this is not the old IMS data. It has been fully reviewed to take into account lighter, stiff yachts.

“I believe the fact that it’s transparent, fair and has got an age allowance, are very key factors for all yachts. John Anderson and I have been pursing a laser system of measurement that will be quicker and more economical than old-fashioned wanding.

“It has yet to be sanctioned by Yachting Australia but that depends on time and more information being put forward to them.”

Having the national rating authority processing measurement data and issuing certificates would avoid having to wait in a single processing queue. The International Sailing Federation had sanctioned ORCI and recognised only ORCI as the rating system to be used for offshore world championships.


What is ORC International?

ORC International continues to use the IMS platform of multiple modules from measurement to scoring, however the Velocity Prediction Program software has been completely re-written.

The major technical factors that have been given extra attention and adjustment include:

* A new aero model with a different evaluation of sail forces with heel angle
* Implementation of Code Zero sails
* A new Residuary Resistance curve (part of the total resistance of the boat)
* A new Righting Moment evaluation
* A new formulation for effective draft of wings and bulb keels.

ORCi aims to favour light boats with a high stability and disadvantage boats with low stability and a low length/volume ratio. It gives a relative advantage to keels having a bulb and reduces the length extension for immersed transoms.

Fietje Judel, co-designer with Rolf Vrolijk of successful offshore racers for many years and a member of the ORC’s technical committee that worked on ORCI, says there had clearly been the need to modernise the IMS rule. The new rule will produce better ratings for the newer boats in the existing fleet.

“I believe that in the future no-one will blame the ORC rules for creating slow, tender and heavy boats. Light displacement and stiff boats with a lot of sail area will be treated considerably better than in the past. They will not achieve a guarantee for winning, like sometimes happens with so-called ‘low tech’ rules, but a well-campaigned light and stiff boat will now be able to win trophies.

“So the balance between the typical series production cruiser-racer and the more exciting racing boat has been moved a bit towards the racing yacht. That does not mean that the ‘normal’ boat has no chance any longer. They can still win, but it will not be as easy as before.”

ORC chief measurer Nicola Sironi, in further explaining the effect of the new rule on the existing fleet, said: “All boats will be faster, on average between four and six seconds/mile GPH. The most favoured are the J-Boats, traditionally too penalised by IMS, the Open classes, the GP classes, the TP52s and all those following the contemporary trend towards more sail area and less weight for a given length who will get a GPH very close to the 2007 IMS value.

“The most penalised at the other end of the test run are the old Holland-designed "Polaris 33" and [the 40-year-old S&S-designed] "Sunstone" together with several other old boats traditionally showing to be over-competitive in large IMS fleets.”


How it works ?

The ORC explains on its web site that ORC International does not compare boats, like any other traditional rating system, but the capability of the race crew.

The rule uses mathematical models and a large number of measurements, including hull lines, to calculate the theoretical time that a boat should complete a given race course in the given conditions. The boat that achieves the best corrected time is the one that completes the course in the shortest possible time relative to this theoretical limit.

The race is against the clock and not necessarily against opponents as any deviation from sailing the fastest track around the course will result in a lower corrected time performance. And finding holes in the rule to ‘adjust’ the boat’s rating not help much either, as that put extra demands on crew performance.

ORCi ratings are a total of ratings for various conditions: wind strength of 6, 8, 10, 12, 14, 16 and 20 knots; direction of true wind from close-hauled to 52, 60, 79, 90, 110, 120, 135, 150 and 180 degrees.

With this data it is possible to establish a polar diagram that shows the speed of the boat in relation to wind strength and direction. This enables sailors to compare the speed of their boat to theoretical speeds from their rating certificate. It also gives them the opportunity to learn the trim of their boat to achieve the best possible speed in any particular conditions.

The computer program that produces polar diagrams consists of two parts: LPP (lines processing program) and VPP (velocity prediction program). LPP calculates hydrostatic date like wetted surface, displacement and stability. These are necessary inputs for the VPP program, which creates a computer simulation of the boat’s performance based on scientific research of boat hulls in hydrodynamic basins, sails in aerodynamic tunnels and measurements taken on real boats.

Hull resistance is calculated in sailing trim with the total crew weight and equipment on board for various angles of inclination and wind strength. Forces that propel and heel the boat are calculated for all possible combinations of sails, along with a choice of the optimal combination for the given wind conditions.

ORC International certificates have quite a large amount of data that allows for several ways to calculate corrected times, including simple scoring options with just one, two or three scoring coefficients.

ORCi allows for different ratings in a race depending on weather conditions and the course type. Thus a heavy boat with smaller sail area will be rated as slow in light winds, but faster in stronger winds; boats with deep keels will be rated fast upwind, just as boats with smaller keels will be rated fast downwind.

The ORC says that ORCi is at its best in around-the-buoys racing where the course is defined with three items: compass bearing, length of leg and wind direction on each leg of the course. The course definition is taking into account how many beats, reaches or runs a boat was sailing and the wind speed used for calculating corrected times based on the boat’s theoretical performance in such conditions.

ORCi also offers different scoring methods, giving race organisers the option to choose the best one for their local conditions, including size of boats, type of course or wind conditions.


Bob Ross
Australian Sailing