the NHC handicap system

Birdseye

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I wrote this explanation of the system in response to the mis perceptions that there are of NHC. I checked the detail at the time with both the RYA and RORC so it should be correct if simplified. The keen IRC man who is contemptuous of NHC might like to read for a more nuanced reaction.

What's wrong with NYC?
I think it's fair to say that NYC hasn't been received with universal joy . Indeed, not too long after it was introduced when chatting with a table of at least three quarters of the regular racers in a series, every one of those present reckoned that the new handicaps put their boat at a real disadvantage to everyone else ! Think about it ?
This short note explains the way NHC works, some of its faults as well as its advantages and will hopefully counter some of the common misconceptions. So how does it work?

Base NHC handicaps
To devise the individual base handicaps , the RYA turned for help to the RORC who calculate the IRC handicaps . Together they devised a simplified version of the IRC calculation algorithm using basic boat dimensions to predict boat performance. It needed to be a simplified system, because unlike the IRC, the RYA had to cater for a huge range of sometimes quite old boats for which only limited and sometimes unreliable dimension data was available.

When statisticians want to compare two sets of data they calculate something called a correlation coefficient. This is a number varying from +1 through zero to -1 . A correlation of +1 is two sets of numbers marching in lock step whilst zero is two sets of numbers that are totally unrelated. Doing the calculation for IRC and NHC gives a very high 0.9 which proves a hugely close tie between the two handicaps. Interestingly, the correlation between NHC and Byron is much worse at 0.125

Handicap adjustment
NHC is a performance based system just as PY was and for example a golf or horse racing handicap is. So what the RYA then needed was a standard method of adjusting the individual handicaps following each race in a series . The maths of the system chosen isn't that complicated but I doubt that many people want to know the equations involved. So here instead is a simple summary of the way the system works and all you need to know is the significance of a what is called a “standard deviation”..Again its a calculation and its significance is that in a series of random events, like good or bad performance in a race, there is only a 1 in three chance of an event being more than one standard deviation from the mean.
So the computer program called HAL works as follows:
1/ After each race, the finishing order is worked out in the usual way by multiplying a boats elapsed time by its handicap at the at the start to give a corrected time, and then ranking the fleet on the basis of these corrected times.
2/ HAL then works out a handicap number for each finisher which would have meant every boat finishing in a dead heat.
3/ The next step is to calculate your handicap for the next race which HAL does by blending your starting handicap with your handicap under 2 above. But in doing this it only takes into account 30% of the difference. As an illustration, if your start handicap was 0.9 and your handicap from 2/ above was 0.93, HAL will give you a handicap of 0.91 for the next race.
4// But what about those boats who for unusual reasons do particularly badly or wildly well in just that one race? The extreme performers who are more than one standard deviation from the mean. It could be, for example, that after half the fleet had finished the wind died to near nothing. So to prevent excessive large adjustments, HAL trets these boats as if they had finished at the time corresponding to one standard deviation.
5/ The final step that HAL takes is one to prevent the drift up or down of all the handicaps in a fleet. It does this in effect by adjusting all the new post race handicaps so that on average they are close to the base NHC handicap number. This doesnt alter the relativities between boats – they all move up or down together including those who didnt even turn out .

The misconceptions
So let's deal with a few, together with some of the strengths and weaknesses of NHC:
1/ The race officer can fiddle the handicaps and look after his pals. Leaving aside that we don't have race officers like that, no he can't. The post race handicap adjustment is computer generated.
2/ Bad sailors can win in NHC. No they can't unless they start as bad sailors and significantly improve. NHC rewards those who do just a bit better every race. Even then it takes a long time for the handicap starting at the base number to fall with bad performance until the boat starts finishing in the top half and the handicap starts climbing again. Remember the 30%
3/ You can game NHC by sailing badly until your handicap is low and then sailing well. To a very limited extent, you can cheat in this way, just as you can with self measurement in IRC. Or indeed by missing marks, or hiring hot shot crew.
4/ NHC punishes you for sailing well. Yes it takes 30% of your out performance away from you each race, so you have to do a bit better each time. But it does avoid the situation where the same boat is winning all the time and the losers simply can never compete.
5/ NHC base numbers are over simple and it takes time for a handicap to reflect reality. True. For some reason the RYA dropped the old PY adjustment factors for things like twin keels. small sails, 3 blade props.
There are Pro and Con for the two basic handicap types, and the proponents of each need to recognise that they are designed for different types of racer. In the absence of a pure one make fleet, the keen racers will nearly always go for a design based handicap like IRC recognising that to a significant degree he will have to email and man his boat to the appropriate standard if he wishes to win. A family sailor in a non racing type of boat and simply wanting some Sunday fun will mostly code a performance based system that will still give him a real chance even if he is sailing a 30 year old bilge Keeler with its original sails and all his cruising gear on board. Horses for courses.
What is true of either handicap system is that they only really work well with similar boats. No handicap that will cover an Impala and a J109 in 10 kn wind and a neap tide will work in 25kn breeze and a spring tide.
 

lw395

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TBH your other thread reinforces its image as the No Hoper's Comedy.
A refuge for crap sailors who don't know the rules and aren't in a hurry to improve.

I think along the with changes to dinghy PY it's a conspiracy to promote One Design racing.
I do a mix of racing. The OD stuff we take seriously. PY is fun on the water, we're not really bothered where the spreadsheet puts us, we only take it seriously in terms of how we do against people we respect in comparable boats. It 's social and I'm all in favour of the trophies being shared around a bit.
Low budget yacht racing is an evening out with some mates, again we have our arch rivals on the water. A lot of the fleet are just moving hazards really.
Bigger budget yacht racing is often much the same except there are a few highly organised boats and usually a few full of obnoxious people.
The odd outing in dayboats like Squibs or XOD or Etchells is a much better standard.
When you can really enjoy a race and come mid fleet, that's good racing, you can learn from people you respect.
 

lw395

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Racing is actually mostly about people.
The boats are just equipment which enables the game.
The people racing NHC and caring at all about the results don't earn much respect as racers.
If you've got good people to race against, the result are not so important. So the handicapping scheme is not so important. But NHC seems to have driven a wedge between its apologists and the respectable racers.

It's a great shame there are no decent cruiser OD classes any more at a halfway affordable level.
Back in the day, if you did OK in Sigma 33s or similar, people knew that meant you were a pretty decent sailor.
 

Praxinoscope

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Although the RYA dropped the PY adjustments for twin keels etc. there are a some designs which a different handicap has been awarded for bilge keel, the Sadler 25 has two handicap ratings, 836 and 841. The strange thing is that the lower h/c (836) has been awarded to the fin keel version and the bilge keel the higher (841). This must be an error surely?
The NHC is not perfect, I don’t think there is a perfect h/c system, they all compromise, but it does at least remove some of the points that were for ever argued over in the PY, and still opens club racing up to those who are more cruising oriented but enjoy the occasional club race.
 

lpdsn

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I believe the NHC handicap system is based on the ECHO handicap in use in Ireland. It rewards improvement, which could still be bad sailing, and it is surprising how much effort seems to be put into massaging it. The key thing though is that it is dual-scored with IRC, so the good boats race under IRC yet ECHO gives the poorer boats hope as they move up the fleet and encourages them to keep trying.
 

lw395

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Although the RYA dropped the PY adjustments for twin keels etc. there are a some designs which a different handicap has been awarded for bilge keel, the Sadler 25 has two handicap ratings, 836 and 841. The strange thing is that the lower h/c (836) has been awarded to the fin keel version and the bilge keel the higher (841). This must be an error surely?
....
The difference is 0.6% or 21 seconds in an hour.
If you think any PY is that accurate, you have more faith than I do.
 

dunedin

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The NHC is not perfect, I don’t think there is a perfect h/c system, they all compromise, but it does at least remove some of the points that were for ever argued over in the PY.

Out of interest what do you see as the improvements of NHC over PY?

Many years back I used to do occasional dinghy races under PY (most racing being One Design class racing). Whilst not perfect (some boats were light wind bandits, like Albacores, others like 420 unbeatable in strong winds), at least the system was readily understood and credible. Importantly, at least for dinghy classes, it was not a golf style individual handicap, but one set for the class of boat as a whole. Therefore sailing better than others was rewarded.

As an ex dinghy racer and owner of an efficient sailing yacht, I sometimes wonder about doing some occasional racing. But whilst I would consider doing this under a boat based PY, or a cheap and simple boat rating, the personal handicap element of NHC would not appeal at all.
So NHC is not encouraging me to do any club racing.
 

Praxinoscope

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Out of interest what do you see as the improvements of NHC over PY?

Many years back I used to do occasional dinghy races under PY (most racing being One Design class racing). Whilst not perfect (some boats were light wind bandits, like Albacores, others like 420 unbeatable in strong winds), at least the system was readily understood and credible. Importantly, at least for dinghy classes, it was not a golf style individual handicap, but one set for the class of boat as a whole. Therefore sailing better than others was rewarded.

As an ex dinghy racer and owner of an efficient sailing yacht, I sometimes wonder about doing some occasional racing. But whilst I would consider doing this under a boat based PY, or a cheap and simple boat rating, the personal handicap element of NHC would not appeal at all.
So NHC is not encouraging me to do any club racing.


I have on earler posts said that I quite liked PY and felt it a shame that it was dropped by the RYA, although I can see why they did as returns were dwindling making it extremely difficult to maintain the base handicaps.
I still remember the arguements over the additional allowances ‘you rated him as a 3 blade prop but he changed it to a 2 blade last week’ . Well as OOD one has to rely upon the competitor advising you of any changes that might affect the h/c
and on something like this you can hardly dive down and under his boat and check. This was just one example, by removing all these additional computations theoretically NHC avoids these situations, but wheteher this makes it fairer? Lets give it a few years to settle down and see.
I don’t particuarly like having to rely on a computer program to calculate the results and revised h/c’s but to do it manually would be impossible unless you are a mathmatical genius.
As Insaid in my post I don’t think there is a perfect h/c sytem, PY worked reasonably well and it looks as if NHC will work reasonably well,the great advantage of both these methods is that the casual racer doesn’t have to pay to have their boat measured which encourages those club members who might be hesitating to join in the racing but doesn’t have a measurement certificate for their boat to join in.
 

lw395

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I have on earler posts said that I quite liked PY and felt it a shame that it was dropped by the RYA, although I can see why they did as returns were dwindling making it extremely difficult to maintain the base handicaps.
I still remember the arguements over the additional allowances ‘you rated him as a 3 blade prop but he changed it to a 2 blade last week’ . Well as OOD one has to rely upon the competitor advising you of any changes that might affect the h/c.....
The PY data for yachts does not really date terribly quickly, if the object of the game is to rate the potential of the various designs.
A Co32 or a Sonata are pretty much the same thing as they've been forever, the data from the last 30 years is still valid.
But PY is not viewed like that by the RYA, they want clubs to bugger about with the numbers in the same way as for NHC, except on a class basis rather than individual boats.
No club I've ever been in has done this.

Most club racing around the Solent seems to be 'club ratings' which are mysterious numbers generated by committees in dimly lit rooms or some unaccountable bloke. Often these numbers look suspiciously like ripped off IRC ratings from the first boat which springs to mind as looking similar. When I once had to find (invent) a number for some obscure boats, I drew graphs of PY, IRC, ISC, IOR and some european numbers for a range of boats which looked like they were designed in the same eras. A bit of armwaving about sail areas and waterline lengths, throw a dart at the right area of the graph.
It worked well enough. The results they got looked about right for how they sailed.
If you play with the results and ratings after the event, the rating usually has to be grossly wrong to change the outcomes at the prizegiving.
Half the time with club cruisers, just having a rating proportional to sqrtL would be near enough.
 

Birdseye

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Out of interest what do you see as the improvements of NHC over PY?

PY was no longer viable because it was based on race results and the number of club race officers sending results data to the RYA gradually got down to single figures. Hence the decision to change toi base numbers calculated from design data.

The major improvement is that the race by race update system is standardiused and computerised to get rid of the favouritism or accusations of favouritism involved when ROs did the adjustments.

Otherwise the system is really the same as PY except that mathematically its the reciprocal

Many years back I used to do occasional dinghy races under PY (most racing being One Design class racing). Whilst not perfect (some boats were light wind bandits, like Albacores, others like 420 unbeatable in strong winds), at least the system was readily understood and credible. Importantly, at least for dinghy classes, it was not a golf style individual handicap, but one set for the class of boat as a whole. Therefore sailing better than others was rewarded.

As an ex dinghy racer and owner of an efficient sailing yacht, I sometimes wonder about doing some occasional racing. But whilst I would consider doing this under a boat based PY, or a cheap and simple boat rating, the personal handicap element of NHC would not appeal at all.
So NHC is not encouraging me to do any club racing.

PY was meant to be adjusted race by race according to performance. many clubs didnt do that but used PY numbers as a sort of cheepo IRC you didnt have to pay for measurement. You can use NHC like that if you want.

In fact you can handicap skippers based on anything your club choses to use for club racing.
 

sctzilla

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My club is planning to use the RYA NHC performance handicap system. It looks really good and We thought it will be very useful.

I saw the excel calculation at National Handicap for Cruisers (NHC) | Racing | RYA - Royal Yachting Association

I have 3 questions I like some advice on.

1. Let's say we have 10 boats and 3 boats did not start (DNF), disqualified (DQ) or did not finish (DNF), what numbers do we put into the Overview sheet? I tried putting 0 or 99999 and this affected the calculations

2. If we have more than 25 boats participating and in the excel, there are only rows for 21 boats, how can we duplicate the rows without affecting the calculation?

3. If we hold more than 6 races but the excel sheets provided for only 6 races, how can we add more columns without affecting the calculation?

Thank you very much!
 

Birdseye

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We have been using the NHC system for some years now. Yes there is some validity in LW395's comments because it does rewards the most improved rather than the best but then IRC rewards the wealthiest rather than the best. The only truly fair racing is in one designs and with iron clad rules but that seems to have almost disappeared in cruisers.

I was not aware of the RYA spreadsheet. Certainly there are two proper software packages that the RYA recommend to be used and they do the job in the way that the original handicap system designer intended. One is valled Hals Racing Results and is FOC - cant remember the name of the other.

The base handicaps for NHC use a simplified version of the IRC rating software as supplied by the RORC. NHC simply adds a layer of performance based adjustments to those numbers as happens in golf or in horse racing. However you need to be careful to make sure that you start off at base number for different fleets because the adjustments to your handicap recognise your performance relative to other members of the fleet
 

TernVI

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At the end of the day, if you need to get a nice number on the spreadsheet to say you've enjoyed the race, it's a waste of time.
Handicap racing, enjoy it on the water, laugh at the spreadsheet.

When you analyse the season's results, are all the wrong people taking home all the trophies in a wheelbarrow?
Mostly it does no harm if a random foible of the handicap system spreads the prizes around a bit.
We know who we respect as racers on the water.
We know who we enjoy racing against, boat against boat.
Top tip, if you want to do well, finish all the races.
 

flaming

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but then IRC rewards the wealthiest rather than the best.
Maybe in your neck of the woods, but it doesn't matter how tricked out your boat is in the Solent, if you can't sail well you won't win.

What we all want is OD. But for various reasons big boat OD has withered and died in the UK.

If your options then are NHC and IRC, there is no contest if what you are trying to do is provide racing that recognises the best team every time out.

As I've said to you a number of times over the years, the problem you are having competing against the IRC boats in your area is not the rating system but the disparity in terms of the effort put into the racing. IRC (or any other measurement system) is perfectly able to provide good racing when the participants are largely putting in the same effort. So for example if all the boats are using cruising sails and are antifouled and have cruising paraphernalia on board then the rating system will cope. But as soon as someone strips their boat out, or buys a set of carbon sails, or dry sails their boat etc then the rating system does not compensate.

The answer, as ever, is not actually about the rating system used, it's about getting the fleet to agree to sail at a level. The RC35 fleet in Scotland is a good example of this. They race under IRC within a tight band, and in addition to the normal IRC rules they have some additional ones. For example the boats have to be kept afloat during the season and antifouled. And they are limited to the number of sail purchases. Sounds like this a little way above where you are racing in terms of the "effort" but it shows a path.

There is nothing stopping your club from saying "right, we're going to use IRC, but we're going to have 2 fleets. One with the IRC rules only, and another where fancy sails are banned and boats must be antifouled and have x number of saucepans on board etc." The best racing is had when the participants find a level, whether or not that is done officially or by a form of mutual consent. Whether this is done under NHC or IRC or anything else is very much a secondary consideration.
 

TernVI

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Wot Flaming said.
Plus, just like in dinghy racing, all handicap systems fall apart if the boats are not 'similar'.
My dinghy club, I can look at the weather and the course and tell you who will win 90% of the time.
Symmetrical vs asy kite or no kite. Course angles matter.
Falling wind in evening races punish slower boats
Boats which surf or plane quickly vs heavier ones.
Tide can help or hinder slow boats.

Some of this might average out over a series or a season. Or it might not.
Luckily, we don't care.
We race to enjoy racing on the water.

Nobody has much faith in any of the yardstick systems, when boats are dissimilar.
And when boats are similar, races are won or lost by smaller margins than the uncertainty in a yacht's yardstick...
 

Praxinoscope

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If racing is your main enjoyment then great use IRC, one of the other 'full measurement' systems or even go One Design, however the advantage with H/C system such as NHC or the old PY is that it helps to encourage the predominantly cruising sailors to have a go at racing, without having to invest in renewable measurement certificates, and especially when the club regatta comes around and you want as many members to participate in the event.
Added to which there are numerous small clubs around the country that just don't have large enough fleets to maintain a race programme without the addition of the cruising boats, the adoption of H/C's such as NHC by these smaller clubs at least keeps racing alive in their area, even if it is a bit 'scratch' at times.
I did like the old PY, but accept that it relied very much on returns to RYA each year to remain functional, however the NHC seems to do a reasonable job, it's not perfect, but at least it does provide a basis to work from when ones fleet can comprise of anything from a Seawych to a Fulmar.
 
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