Please select your home edition
Edition
Bakewell-White Yacht Design

ORC Worlds fleet ITC analysis

by ORC Press on 5 Jul 2011
ORC Worlds © Max Ranchi Photography http://www.maxranchi.com
Here is a preliminary parametric study made to evaluate performance of ORC rating system 4 July 2011.

For the two days of inshore racing at the ORCi World Champsionship that concluded a week ago in Cres, International Technical Committee (ITC) Chairman Alessandro Nazareth was on hand to observe the fleet and the racing.


He has made some preliminary observations based on some parametric analyses of the top half finishing designs in Class A and Class B, looking at the following non-dimensional parameters: LVR; Sqrt(UP SA) / VOL^0.33; Sqrt(DWN SA) / VOL^0.33; UP SA / WS; DWN SA / WS; DRAFT / IMS L; and RM /DEF RM.

A summary of the observations Nazareth has made of Class A are as follows:

All the top-finishing boats (Aniene TP52, Calipso IV Cookson 50, Airis GP42, Enfant Terrible Farr 40, Altair 3 Felci 50, Marina Kastela GS 56) have all their non-dimensional parameters on the more powerful side, meaning that the winning boats have very powerful characteristics.

They are the longer and lighter boats, they have greater sail area compared to displacement and wetted surface, and they have deeper keels and so are stiffer.

The only design that has smaller ratios but is still among the top-scoring boats is the very well sailed Man GS 4205R, a 'boxy boat' with a conventional bulb-less keel, but the quasi-sistership Bohemia Express has changed their keel into adding a T bulb and thus has a higher RM.

My very quick conclusion is that older 'boxy' boats can survive because their narrow shape still helps them on up-and-down courses, but that the power of being light or with more sail area is allowing the more 'modern' designs to be competitive with them on corrected time, and often to beat them, even on windward-leeward courses. Perhaps if there were more wind we would have seen this effect even more pronounced on the offshore races.

Class B
It is interesting to note that the Class B designs are composed completely of less powered boats. For the LVR ratio, only 5 boats have more than 5.5, a value smaller than for Class A.

Some top boats (Scugnizza, Rewind, Italia 10.98) are on the lighter (5.7) side but the NM37, Comet 38, GS40, X37 are among the top boats as well but are averaging values of 5.3-5.4.

For UP SA/VOL only very few reach the minimum of group A (5.0) and they are the lighter ones (like Scugnizza) and those GS40's with overlapping jibs. The NM37, X37 and Comet 38 have average values (4.7) of the larger group.

For UPSA/WS only the two GS40's with genoas reach the minimum of Class A (3.0), with the remaining having very low sail areas compared to WS.

Downwind in the top boats only Scugnizza, Scricca and the X-35 have sail areas in the average of Class A (both in SA/VOL and SA/WS).

Looking at RM/DEF RM, very few are above 1.0, which means that very few have stabilities higher than what ORC is estimating. Only the Comet 38 and Salona 34 has stability in the range of the TP52, GP42 and Cookson 50. This characteristic of the NM 38 may account for the favorable upwind speed of the NM 38.

This is a preliminary analysis, with a more in-depth study being prepared for the next ORC column in Seahorse magazine.

Other ITC news is that a Working Group studying Residual Resistance is meeting in Delft over 16-18 July to examine how to improve this algorithm in the ORC VPP.

For more information and parametric plots that accompany this analysis, and for more information about ORC rules, rating systems and events, visit www.orc.org.
upffront 660x82Newport Boat Show 2016 660x82Wildwind 2016 660x82

Related Articles

OK Dinghy World Championship - Danes dominate glamour first day
Jørgen Svendsen (DEN) and Bo Petersen (DEN) shared the spoils on the first day of the 2016 OK Dinghy World Championship 2016 OK Dinghy World Championship - Jørgen Svendsen (DEN) and Bo Petersen (DEN) shared the spoils on the first day of the 2016 OK Dinghy World Championship in Quiberon, France after a glamour day on the water with unbroken sunshine and a building sea breeze that topped out at 16-18 knots. An impressive 105 OK Dinghies from 10 nations completed registration.
Posted today at 3:35 am
52 Super Series – Puerto Portals Sailing Week – Bouncing back on Day 1
Quantum Racing pretty much carried on from where they left off in Sardinia earlier this month, ferociously consistent Quantum Racing pretty much carried on from where they left off in Sardinia earlier this month, ferociously consistent and proving the value of every point gained on each race course. After their ninth and tenth places respectively at the Audi Settimana delle Bocche Vladimir Liubomirov’s Bronenosec and Takashi Okura’s Sled both bounced back with a strong opening day to the third regatta of the five
Posted on 25 Jul
52 Super Series – Puerto Portals Sailing Week – Races 1 and 2 images
Photographer Max Ranchi has provided this gallery of images from races one and two Photographer Max Ranchi has provided this gallery of images from races one and two
Posted on 25 Jul
New challenges for Oman Air at halfway stage of Extreme Sailing Series
Race organisers have extended the race area on the River Elbe to cater for the higher speeds of the new foiling GC32s. Race organisers have extended the race area on the River Elbe to cater for the higher speeds of the new foiling GC32s but Oman Air skipper Morgan Larson says avoiding errors will still be the biggest challenge if they are to extend their overall lead with their third Act victory of the season.
Posted on 25 Jul
Rolex Swan Cup – A noble approach to sailing
Mention the Swan Cup to any sailor and the feelings evoked are common – great competition in an enviable environment Mention the Swan Cup to any sailor and the feelings evoked are common – great competition in an enviable environment, a prevailing spirit of fair play and an opportunity to sail yachts renowned for their grace, enduring appeal and rich heritage.
Posted on 25 Jul
Comanche's Trans-Atlantic record attempt hits soft spot
Light air zones threaten record-breaking pace as 100ft yacht charges across mid-Atlantic With 1,548 nautical miles left to sail to the finish of the Transatlantic record (as of 08:30 GMT today) at Lizard Point, UK, Comanche remains on course to break Mari Cha IV’s 2003 record. Stan Honey, Comanche navigator, noted this morning: Chilly here. Set the A-3 Gennaker to go deeper. Very flat water. Smooth sailing. Not much wind down low near the cold water. Visibility 10meters.
Posted on 25 Jul
World of Sailing in review - July 2016 edition - Round the Island Race
World Sailing present their July 2016 video magazine featuring the Round the Island race World Sailing present their July 2016 video magazine featuring the Round the Island race (around the Isle of Wight) and preview several personalities and aspects of the upcoming Rio Olympics
Posted on 25 Jul
America’s Cup World Series – More final day images by Ingrid Abery
Ingrid Abery has provided this gallery of images from final day Ingrid Abery has provided this gallery of images from final day
Posted on 25 Jul
America’s Cup World Series – Final race day images by Ingrid Abery
Ingrid Abery provided this gallery of images from final day Ingrid Abery provided this gallery of images from final day
Posted on 25 Jul
PA Consulting and Allen RS Feva Worlds - Practice and opening day
164 boats completed registration and had their practice race just out of the harbour entrance in front of the city beach 2016 PA Consulting/Allen RS Feva World Championship - It’s officially Fiesta Week in Santander! Oh yes, in addition to the traditional massive fair and circus and two public holidays this week there is this year the RS Feva Worlds. 164 boats completed registration and had their practice race just out of the harbour entrance in front of the city beach.
Posted on 25 Jul