Dart 15 Forums

Just looked on the RYA website and the PN for una rig is listed as 918 (no surprise). Have the Sport Rig sailors been getting a bit of a move on recently, though? There is a change of -23 so the new number is 860. Bit of a coup for those who believe the class should be una rig only. Don't think there'll be many 2 sail boats attending the TT series events in future.

Anyone have any likely explanations for this change?

I get access denied when I try to download the spreadsheet. Managed to get the PDF OK.

That's a big hit for the 'Sport'.
Ironic after the more favourable shift in SCHRS ratings last year.

Looking at the 'number of races', the Sprint 15 appear to have a very healthy participation in handicap events.
No seperate published figures for 2 up?

Robert wrote:Just looked on the RYA website and the PN for una rig is listed as 918 (no surprise). Have the Sport Rig sailors been getting a bit of a move on recently, though? There is a change of -23 so the new number is 860. Bit of a coup for those who believe the class should be una rig only. Don't think there'll be many 2 sail boats attending the TT series events in future.

Anyone have any likely explanations for this change?

Hi Robert,
Yes this is a baffling change. The new RYA PN for Sport mode requires a Sport mode boat to be 6.3% faster than a unarig boat (up from 3.8%) faster in 2012.
Years ago in the mid 90's the RYA numbers for standard and Sport were 97 and 93 (i.e. 4.1% faster) and I reckoned that 97 and 94 would have been fairer and started to collect statistics but I never got enough for them to be significant. I have always been of the opinion it is harder to get the same position in a handicap race if I sailed Sport mode rather than Standard mode on the old ratings.

The change is even more baffling because:
a) Most of the really good Sport Sailors are not sailing it anymore. e.g. George Carter, Robin Leather, Laurie Gustar and many others at Gurnard, Kyle Stoneham and even Steve Sawford seldom sails Sport mode anymore. Mike Cemms boat is for sale but I'm not sure if he sailed it much last year.
b) the RYA rating is based on 358 returns yet it was based on 330 returns last year.

Some pretty good sailors must have been sailing Sport mode in handicap events somewhere last year. Does anyone know who they are? It might just be one really good sailor who has sailed a lot in handicap events. It is likely to be at Club(s) on big open water where they do not have a separate Catamaran so the Cats have to sail with the monohulls.

As a class we do not have to use the RYA number and it would be my preference that we do not adopt the 860 for our open events (I'll sound out the committee on this) but this does not help in handicap open events so I would like to understand where the hot sailors are.
ANY IDEAS FOLKS? If you know please let us know.

Cheers

Bob

PS SCHRS which is based on a formula reckons that the Sport mode should be 8.6% faster than the standard mode. We have never found sailors can perform to this level and have put it down to a quirk in the formula (or a weakness in the Sport mode design that it cannot consistently perform to the formula). For this reason we have never adopted SCHRS ratings for our class events and choose to use PY ratings as they reflect actual data rather than theoretical calculations.

PPS I see that SCHRS requires that the DX configuration is 16.8% faster than standard mode. This must be incredibly tough.

Another thought.
Clubs are encouraged to adjust the handicaps to suit their conditions and their fleets. I see that Queen Mary use 950 and 915 for the Sprint 15 and the Sport configurations. Draycote use 929 and 905. It depends on your club how they allow such changes. At Grafham we have very few Sport mode sailors and they are hopeless - so we have no data on the Sport mode. Our data on the standard mode reflects a strong fleet which perform better (faster) than the RYA 918 so no cause (benefit) to push to update..........
Cheers
Bob
Andrew - what happens at Thorpe Bay?

For club racing at Thorpe Bay, we all sail una-rig. We race with this format for two reasons. 1) It promotes one-design racing. 2) It is much easier to attract newcomers to the sport, without their first having to learn how to trapeze.

The two-sail option is used where someone takes a crew. Same PY of course. In the past, I have taken someone for a demonstration sail. I like to race at the same time, but wouldn't stand a chance if everyone else was sailing Sport mode.

Why does the SCHRS system not favour the Sprint 15 Sport mode which it predicts should be 8.6% faster than standard mode? The SCHRS system is entirely theoretical and has little experimental validation for individual boat designs. Now over the last 20 years the RYA PNs have generally had the Sprint 15 Sport mode ~4% faster than the standard Sprint 15 and we have perceived it to be reasonably fair or even a little harsh. Now I have had many discussions with Simon Longstaff (the past chairman of the SCHRS committee) on the subject. His view is that if the Sprint 15 Sport sailors cannot sail competitively to the SCHRS ratings as the sailors are not good enough. I do not accept that as they are often the same sailors who sail in standard mode. It is my view that the Sprint 15 Sport design does not sail to the formula. The SCHRS formula is complex but the idea behind it is simple. If you increase the sail area by x amount you would expect the boat to become proportionately faster (or by some more complex factor). So we add nearly 2 Sq metres of jib to the 10.5 Sq metres of mainsail and we only go 4% faster. You can clearly see that this is a very poor return for the addition of so much extra sail area. It is easy to understand why to those who sail the boat in a mixed fleet with the standard una-rig boat for the following reasons:
a) the jib is of such a design that it makes little or no contribution upwind, Any extra speed is offset by the degradation in the pointing ability which increases the distance you have to sail. You generally have to sail a few degrees freer to get the benefit of the jib as otherwise it backs the mainsail.
b) it is a big advantage on the reach.
c) downwind it constrains the course sailed (you cannot run directly like with the una-rig as the mainsail backs the jib) and so you have to reach and tack downwind and at wind strengths of force 3 or less the extra speed does not compensate for the extra distance travelled. In force 4-5 winds it is quicker but as the wind strength gets to force 6 or more it is normal to have to furl the jib to prevent a pitch pole.
So for much of the time a Sport mode boat is no faster than a una-rig boat and the speed is very course dependant. Indeed on a windward-leeward course or in light winds it is very difficult to match the speed of a una-rig boat on the water with no handicap correction.
So I believe that the Sport mode does not use extra 19% of sail area very effectively. It is easy to believe if you add that amount of sail to other catamarans or in other ways you would get bigger speed increases. I do not believe there is much the SCHRS system can do to correct it. It is the boat design/effectiveness that is the problem. In yacht racing where they have a formula (like SCHRS) you hear that yachts are designed to perform well with that formula. If catamarans were designed to perform to the SCHRS formula a Sprint 15 Sport would not have been a successful boat.
Fortunately the Sprint 15 Sport variant is successful and it is enjoyable to sail in class racing even if it is not effective when sailed against other Cats under SCHRS ratings. The fact that it is sailed extensively has resulted in it getting an RYA PN which is based on empirical data. For the last 25 years this data has produced a PN which has been approximately 4% faster than the una-rig boat which we judge to be fair. We just need to understand why the RYA have suddenly changed it to a rating which expects it to be 6.3% faster.
In the Class Association we can retain the 883 handicap and the committee are considering doing this at present. It is vitally important we understand the basis for the RYA change to 860 as it effects the way the boat performs in club racing against mono hulls.
Regards
Bob

This is something I'm inclined to leave to the experts. But from a layman's point of view, the RYA seems to have overlooked something. Namely, that the amount sail area should not be the sole criteria.

Calculating a PY of 860 would suggest that Sport mode is enhanced in other ways. For example, is the boat 6.3% lighter? Is the sail plan enhanced with a differently shaped main? etc.

I intend to keep 883 at SSC for club sailing until we know more - obviously for the June TT I will abide by the class decision (which hopefully we know by then).

I have some concern that returns may have been made for some 'special' races - like the Piers and IOSSC island races that may include DX sport, or two ups where they should be 917. Definitely needs challenging with the RYA.

The increase in the Dart 18 PY last year made them more closely aligned with una rig Sprint 15s and gave us some very close handicap results which I would expect knowing the competitors in question.

Several boats changes at SSC over the winter - not quite sure what our fleet size is for a few weeks (24/25 ?). Hope the weather warms up soon !!!!!!!!!!

Steve

Andrew Hannah wrote:This is something I'm inclined to leave to the experts. But from a layman's point of view, the RYA seems to have overlooked something. Namely, that the amount sail area should not be the sole criteria.

Calculating a PY of 860 would suggest that Sport mode is enhanced in other ways. For example, is the boat 6.3% lighter? Is the sail plan enhanced with a differently shaped main? etc.

SCHRS uses calculations based on weight, length, beam, sail area etc. etc. to reach a 'rating' that can be applied in handicap events.

The RYA PY scheme is very different, in that it relys on a dat base of handicap race results over the past 3 years. The numbers the RYA come up with are based on an average performance for the particular class. The sail area of a particular class/configuration does not come into it.
The large drop in the Sport mode PY would suggest that there have been some very favourable results over the past 3 years at the old PY of 883, hence the 'adjustment'.

[quote="Andymac"
The RYA PY scheme is very different, in that it relys on a dat base of handicap race results over the past 3 years. The numbers the RYA come up with are based on an average performance for the particular class. The sail area of a particular class/configuration does not come into it.
The large drop in the Sport mode PY would suggest that there have been some very favourable results over the past 3 years at the old PY of 883, hence the 'adjustment'.[/quote]

Yes Andy,
Right on. But I don't see any hot sailors sailing in Sport mode in handicap races with monohulls in open events which are input to the RYA PYS system. Catamaran races like the 3 piers race do not get loaded as the RYA PYS system cannot deal with SCHRS ratings. This almost certainly excludes Instow and Shanklin too. In fact I know of very few hot Sprint 15 Sport mode sailors sailing outside our events. So we have to conclude either that someone is doing very well in a club handicap series or that there has been an error. That is why I ask if anyone knows of anybody who might be causing such a severe change?
Regards
Bob
PS I think I know that it is not Queen Mary or Draycote(as they have revised the handicap upwards). I think Carsington sail on SCHRS ratings and Ray Gall revised them to give the Sport mode a better chance. Stewart/Simon - what happens at Oxford? Are you cleaning up in the club racing? Any other suggestions?

Hi Bob

Im not cleaning up at Oxford, I joined Stewartby for the winter as I was the only 15 racing at Oxford regularly in the fast fleet. Needed to race boats on a like for like basis to try and find any improvement in sailing. Stewart has not been racing this winter, to cold.

Simon 1970

simon wrote:Hi Bob

Im not cleaning up at Oxford, I joined Stewartby for the winter as I was the only 15 racing at Oxford regularly in the fast fleet. Needed to race boats on a like for like basis to try and find any improvement in sailing. Stewart has not been racing this winter, to cold.

Simon 1970

Simon thanks for the reply. It is the whole of last year that I'm interested in. Were either of you getting good results in the Summer?
Regards
Bob
PS Anyone know if Instow make RYA returns? I suspect that they just sail in catamaran fleets.

Hi Bob

No I didnt have any good results in the summer, oh only on 2 occasions when it was so windy that only the contenders came out to play and I gave them a good kicking.
Stew,Clive and myself did the Wednesday eveings in dying winds and were thrashed.

Hope to see you Sunday


Simon 1970

This is mainly for Bob Carter - to provide background for Queen Mary Handicap Numbers. The following is extracted from an October 2011 email to QM (some?) members.

"Handicap Changes

Various handicap changes will be effective from the start of November, following both the analysis of our Wednesday Evening Series data and discussions with other 'Great Lakes' Clubs based on large flat water venues like ours (Grafham, Rutland, Northampton, Draycote and Chew). This link up has enabled us to pool our experience and adjust handicaps for classes that we do not see regularly in Club racing but do turn up from time to time for Open Pursuits. As usual the handicaps being used will be published in the Notice of Race for the Series."

For info :-

A) the Wednesday Evening Series is the only QM series in which all classes compete on a handicap basis - all other series are subdivided into significant classes of boat, with just 3 handicap classes with relatively small numbers. The Wednesday Evening Series is regarded as THE club series to win and is sailed keenly by most of QM's best sailors (exceptions are usually those who can't make Weds evenings due to work commitments). There can be over 50 boats on the start line some evenings - but not all of them are good.....

B) there are very few occasions when Sport Mode is sailed at QM - usually just me in the month or so before the Sport Nationals, and then only on Sundays, NOT in the Wednesday Evening Series.

I haven't sailed since the Draycote January Winter Traveller, and I may not make it to Grafham. But when I am next at Queen Mary I'll ask who does QM's RYA return, who does the consultation with the other clubs, and from them try to find out more about how we can get info on this unexpected change. Others might try the same at their Club?

I looked at the NDYC website, on their Sprint 15 page http://www.ndyc.org/fleets/sprint-15. I get the impression that normal Sprint 15 racing at Instow is a Sprint 15 Sport class only race, with very limited handicap racing.