moniker ORCi – the European national authorities persevered with the project. They amassed a good database of hull offset files for the popular classes, improved the hull scanning of one-offs, and set up a way of using the designers’ computer files to replace the physical scanning of larger yachts. Meanwhile, the VPP improved due to the diligent work of the ITC. The race management process was streamlined and in the past few years there have been 100-yacht fleets at world and European ORCi championships. This period of relative inactivity for the handicappers was disturbed almost overnight when the Superyacht fleet dis- covered competitive racing. There had always been ad hoc Superyacht regattas in glamorous venues, where the racing was little more than a way of working up a thirst for the post-race party. However, recently the size and sophistication of the yachts had grown, and with it the competi- tive instinct of the owners and their crews. It was back to the early days of the Cumberland Fleet – owners wanted to race their large yachts, which were often not designed nor rigged for racing. In response to this growing interest in racing the Superyacht Racing Association (SYRA) was formed in 2012. Led by the designers, yards and owners, it had a mandate to re- cast the racing rules so that these big boats could race at close quarters on confined courses, and to foster fair sailing. With the co-operation of ISAF the racing rules were quickly agreed and published. This shifted the spotlight onto the handicap rule. Now a way had to be found to equitably handicap a fleet that ranged in length from 25 to 65m and in displace- ment from 30 to 550 tonnes. Quite quickly the pragmatic ‘Bucket Rules’ became inap- propriate, they were just not robust enough to withstand the pressure from well-drilled teams in well-prepared boats. In the spring of 2014 the SYRA took a
bold step to work with the ORC to adapt the existing ORCi VPP for use with the Superyacht fleet. To the untrained eye it was indeed a very bold step. The ORCi worked well for sloop-rigged yachts up to 70ft in length, how could anyone know if the same formulations would work for much larger boats with multi-masted rigs and a diversity of sail-handling systems? But the ORC working party was confident that they could come up with something if we tackled the problem with basic physics. For example, these big boats sail quite slowly so most of their resistance is due to surface friction, and we could measure that very accurately from the hull files supplied by the designers. The rigs were very different, but with the experience of the Wolfson Unit we were able to distil a set of sail coefficients that captured the close-hauled excellence of the sloops and the reaching power of the ketches and schooners. The windage of the high super- structures and radar domes and hoisted furled sails could also be estimated once the dimensions were captured, while the Superyachts were able to supply righting moment and displacement data from their MCA Stability books – removing the need for an inclining test.
The major uncertainty was the dynamic behaviour of the boats. The true Super - yachts are bad at tacking, particularly if they have to furl a headsail to do so, and there is the additional slowing effect of the ocean waves to allow for. If we were hand- icapping a transatlantic race it would be easy – none of these dynamic effects are in play. But for a race around the island of St Barths it’s as much the tacking and gybing as it is the basic speed. But by adapting some existing factors relating to length, displacement and sail area, and by devel- oping some robust new metrics related to the VCG position, the rule can detect the yachts that are least nimble and offer them appropriate handicap relief.
The working party spent the autumn and winter of 2014-15 working on the VPP. When it was first used in anger at the Loro Piana and St Barths Bucket Regattas in March 2015 it was on the 38th itera- tion. Did the ORCsy Rule work? Better than most pundits expected: in the last race of the Bucket after 25 miles of pursuit racing Adela and Elfje were overlapped on the finish line to decide the class winner. Nevertheless, the SYRA and ORC are realistic that this will be a work in progress for several years, and it can never be as robust as the rules for the smaller yachts as there are just too many variables in the Superyacht fleet that don’t appear in ‘normal’ fleets. For a 40m Superyacht one tack can add three or four minutes to her elapsed time, while for more nimble yachts that loss is only 10-15 seconds. The devil will always be in this type of detail. That said, from my point of view this has been a clear demonstration that when carefully developed, VPP-based yacht handicapping offers several important benefits to diverse racing fleets: publication of detailed certificates allows the class to self-police, not to identify possible ‘cheats’ but for oversights and misinterpretations in measurement that are inevitable when the yachts only race three or four times a year; issuing handicaps that depend on wind strength and course mix is also very important for these boats – a light-air sluggard can often be very fast in a strong breeze. making the rule transparent via a published methodology and the ability to run trial certificates allows the owners, designers, yards and the sailmakers to confidently plan because they know what the handicap effect of a change will be. It has taken 30 years for the science of yacht performance prediction to demon- strate its utility for yacht handicapping. The success of the ORCsy is just one part of the story…
SEAHORSE 29
q
INGRID ABERY
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72