They have put quite a lot of thought into it and the numbers can change if a fleet dominate the results. The method of coming to the 'HISC figures' can be found on the following link.

These numbers are still not perfect and every dog will have its day. The Solo are generally very good on a light/medium day.

If it is windy and there are a lot of spinnaker legs the RS200 and 29ers are pretty good. 

In other days/courses other boats are better but generally every dog can have it's day. 

On the point of returns, we sail mostly pursuit sailing so not much point 

There have been adjustments in the past though when a class is obviously wrong for our water.

At Netley we also apply a tidal correction factor, though as our tides are not as strong as those at HISC we apply a 'lighter touch' - ditto through our sailing Committee we are happy to amend PYs that seem blatantly wrong. This is not a case of giving a poor boat or sailor a leg up, but a recognition that our waters suit some boats better than others,

Regarding the use of a further correction factor for age amongst the development classes, we're aware of the need to be even handed, so for instance an older IC might well get the PY it would have had some years back. Rather than criticize the Merlins and 12s for trying to be inclusive for their older variants, there is an argument that maybe more classes should be aware of the large numbers of older boats out there. It could be age related, or simply something as simple of  a carbon spars v alloy or a pre-frp/frp split, or as has already been pointed out, if there was a major change adopted by  a class. 

Right now I'm trying to complete the book charting the history of the 5o5 and in the last few days, I've been looking at the changes in hull shapes (but in a bit more detail than in the recent 'One design or two' article). So here you have a fleet that has a clear point of change - boat numbers of 8400 marking the boundary between two quite distinct notions of the hull form. Now if there was class racing for the 5o5 at club level, would it be fair for someone with a good boat, but with a 83xx sail number - to be sailing off the same PY as the later hull forms? 

Ditto the Contender.... it is easy to say "sail a newer boat" and that is of course the answer, but it doesn't do much for inclusivity.

If the above is in part an argument that there might be a better way, would that be a bad thing.

BUT - it would need a top down, fully inclusive coming together of the stakeholders, innovators and wise minds to ensure that any possible solutions are actually 'better' that the current status quo. But this would cut across so many other topics, starting with 'where is the sport going' over the next 30 years (ie, up to 2050) that the likely outcome is that ...nothing will happen!

D

Spot on, if there was an age allowance there may be less unloved boats in the dinghy park, sailing would be more accessible and participation would be up. 

The issue will be separating the results in the returns, this year the list was full of notes saying ‘please separate different versions in returns’ (paraphrasing) 

Current world champion GP14 is 25 years old. Another 25 year old boat was top 5.

Both were home built too........