The Fuller Number

When I did a sum I put the N12 area at 10.5m but notice the website FAQ says 11m.  The basic triangles are 8.4m and I don't see how you get an extra 2.6m, but maybe it is as much as that.

i think that 5kg out of the boat weight is much more significant than 5kg out of either the crew weight or the all up weight.  Dynamic weight is much more less of a penalty than weight that cannot be moved around the boat.  When we reduced all up weight in the N12 by 10kg in two 5kg instalments 20 years ago (sailor weights did not change) the difference was pretty impressive.  5 points is essentially a bad tack and then having to sail in bad air.

Hull forms that plane earlier and longer have a great advantage ... once planing it matters much less what length the hull.  A light 13ft boat planing v a 15ft 'traditional' boat stuck in displacement ?  Pretty obvious .. Sure when both are in displacement length can be very useful ... but modern boats or ones designed or upgraded to plane early are much more common now. 

When both are planing it is a slightly different case but as was particularly obvious with boards when 'fullers roamed the earth' in pre-history waggling a long hull around with a (now un-needed) load of it in the air is simply not fast.   A part parallel can be seen with the foiling 600 v Int Moth ... now which is faster ?   The assumption that 'more sail' = 'faster' is not always correct either and so on.

This debate will run and run as it is great forum fodder ... there are hundreds of factors that can be important on occasion and in certain conditons.  Development classes very reason to live is that 'rules' can in practical terms only 'fix' some variables and inventive developers will always strive to 'better' them.  

Want 'fairer' handicap numbers ?  Well my bet is that future handicap approaches likely to be credible will still remain 'wet' results based approaches as they are very 'doable' and avoid the complexity and limitations of boat based formulas.  The only question will be on what basis or samples in the future.  All want numbers that 'capture' the potential of the craft and not much else. Now do we mean recent class examples with good crews or not ? 

Formulas that have ambitions to handicap everything under the sun 'fairly' will have to and inevitably become more and more complex ... how many 'exceptions' are out there ?  (A. Well quite a few really - ask on this forum for a start !) .  'Lead into gold' ...not totally impossible perhaps but as likely to drive the 'chemists' round the bend on the way there as well.

Mike L.

The N12 being so developed will be an outlier in this analysis ... 

Originally posted by JimC Originally posted by iGRF A handicap changing because some physical alteration to the craft has taken place is one thing, That's a measured rating system, which the Portsmouth yardstick isn't. Yes I realise that, it's what I'd like to see constructed as a viable alternative a la SCHRS with no reason not to work in concert to what we have at the moment Kipling wrote "There are nine and sixty ways of constructing tribal lays,/And every single one of them is right!", and there are probably 69 ways of managing handicap racing, and they're all correct too. I don't think the current scheme (which of course is in the middle of major change of philosophy) is perfect, or ideal, or anything else, but I do think its probably the most practical system the sport can manage at the moment, and what follows is my personal understanding/interpretation. I do accept that and appreciate all that has gone before and didn't actually believe it was that bad before this latest seizmic shift Over the years its changed. It started out in the 1950s simply as an average of the handicaps actually in use at as many clubs as possible, with a means of normalising each clubs data. It moved, fairly quickly I think, to club officers saying what they thought the handicap should be, rather than what they had used that season. That was how it continued until quite recently, based on the club handicap numbers with various increasingly sophisticated numerical tools to make the club numbers as comparable as possible and things like spreadsheets for the clubs to use to adjust their numbers. The criticism of that over the years was that the clubs had become too complacent and were not putting enough effort into recommending variant numbers. When I look at the historical data I've put together I think there's a little evidence that there weren't as many numbers changing as much in the 2000s as there were in the 1980s. I suspect part of that is pyschological, because 90 -> 91 feels like a smaller change than 900-910... Anyway, that's changed now, and the system is in the middle of moving away from the method of numbers based on club recommendations to a new method of numbers based on actual club results - the web system. This brings a whole number of advantages, and also a number of disadvantages, because nothing's perfect. The systems aren't as different as they sound, because the actual functionality behind the web system is using the maths in the tools that were made available to the clubs to calculate the equivalent of club recommended numbers, and then aggregate the club numbers in the same way. Again, I appreciate all that and thanks for detailing it so succinctly, I have been around since the days when we worked out that the Original Windsurfer could compete at 120, but were told we couldn't because of what happened when we began to plane, rather like foiling moths today. However there must be some form of formulaic interpretation built into the Sailwave system when it recommends a number, do you know the maths behind that, and are you absolutely confident in it? So the new system effectively calculates recommendations for every club, whereas before it was considered that many clubs didn't bother to do the calculations and just returned the standard numbers every year. So a big advantage of the new system is that it much more closely represents what's happening on the water, and a feature is that the opinion of the club officer about what the handicap should be, whether beneficial or otherwise, is reduced in influence. Accepted, but let me anecdotally tell you what happened last night when I was OOD, the guy that should have been in the race box failed to show, so I'm on the water all night having to place then recover the marks, order a course shortening because it was getting dark and the race was being timed then shortened by the daughter of the helm that was in the lead in a Hornet, the chasing boat, a Merlin which took 50 secs to even get across the start line due to an error the helm made in tidal assumption, so the inevitable politics of that scenario,(the Merlin still won in a fleet of lasers such is its badness)is enough to cope with, the daughter worked out the rests and just refers straight to the RYA list, nobody wants to be the person to say the Merlin shouldn't have won, which clearly it shouldn't. So a small under resourced club has no choice but to refer to the greater authority, but when that greater authority is wrong... But the key point about this system is, rightly or wrongly, its not based on the size of the boat, the length of the boat or anything else. Its based on what actually happened on the water over the last 3 seasons. So, unlike all the many Yacht handicapping rules which have come and gone over last 50 years, its immune from designers gaming the measurement system, 'cos there ain't one! On the other hand it does mean its impossible for the RYA team to create handicaps for new boats until there's enough data in the system, and if boats don't maintain a certain level of activity they'll be dropped from the published lists.But what happened over the last three seasons is the impact of a megalomaniacal series dominating the process and swaying the Laser handicap as part of that Agenda So basically, whilst in a measured rating system numbers change because the boats have changed, in an observed performance system, which PYS is, numbers change because the performance on the water has changed, and the system doesn't need to attempt to collect data about boat changes. Nothing wrong with either way of doing things: they're just different. Agreed, but I still feel there's room for a parallel device that can be brought to bear, wether it should have been derived the one from the other however remains up for discussion, I was rather hoping we might also get some Dan Holman input he must have some similar formulaic device, I'm sure from the great minds assembled here, some improvement can be had and we all benefit, thanks again for listing all that. What a great thread this is turning out to be