There are some anomalies in the Parker and Seal base numbers, which are:

Design 	Base Number
SEAL 22   	0.821
PARKER 235	0.856
SEAL 850	0.856
SEAL 26   	0.860
PARKER 21	0.862
SUPER SEAL 	0.879
PARKER 27 	0.888
PARKER 325	0.901
PARKER 275	0.910
PARKER 31	0.948

I think Seal 26 should be Seal 28, and the P235 and P275 ones look wrong!

So: If you do club racing, and your club is using the NHC, could you let us know your personal club NHC number?

Also: in the PSSA sailing instructions, we currently have Portsmouth Yardstick numbers, but with various allowances (eg. type of prop, fixed keel, cruising chute/spinnaker/neither. We're going to have to change that!

My feeling is that we should switch to NHC, (once the anomalies are corrected) and remove all allowances. Do you agree? Should this be discussed at the AGM?

Geoff

Parker 21 / 18 Dawn

My calculation below shows the PY numbers that PSSA is currently using. I have then inverted them to become a TCF (Multiplication rather than Division factor) then, in the third column, I have 'normalised' them to the Super Seal base number as this is the one most likely to be correct. If you compare these values with the new RYA published base numbers you can see the problem.

Design PSSA Inverse 'Normalised' RYA

PY of PN(TCF) TCF Base List

Seal 22 1140 0.8772 0.7525 0.821

Parker 235 1030 0.9709 0.8329 0.856

Seal 850 1080 0.9259 0.7944 0.856

Seal 28 1095 0.9132 0.7835 0.860

Parker 21 1063 0.9407 0.8071 0.862

Super Seal 976 1.0246 0.8790 0.879

Parker 27 976 1.0246 0.8790 0.888

Parker 325 940 1.0638 0.9127 0.901

Parker 275 976 1.0246 0.8790 0.910

Parker 31 950 1.0526 0.9031 0.948

For instance :- under PY there is a 17% difference in speed between the Seal 22 and the Super Seal. Using RYA base number values there is only 6.6% difference. My 'normalised' values mirror the differences more closely ... though not completely.

However, in the RYa's defence, they are not worried too much about base number accuracy as, after each race, the system alters the handicaps for the next race based on the performance of each boat. After a few races they correct themselves to the skill of the individuals and conditions in the local fleet.

After a while, close racing will take place.

If we are only going to have one or two races a year with varying entrants, this system will not work. We would be better to stick to the PYs.

Chris.

Chris.

I agree that the NHC doesn't really work for one-off races, and - given that the PY numbers are well established - it may be better to stick to them, or use your normalised numbers (which will give the same result).

Are you using NHC at RVYC?

Geoff

Parker 21 / 18 Dawn

We have just started using the NHC system for our Frostbite series which started last Sunday. We are not fully convinced that it will work with our short seven race series and with a small number of entries. What we are hoping is, if we keep it going throughout next year, that anomalies will eventually be sorted out.

My calculation was done on a simple mathematical formula which deviates a little as the range of handicap increases ... so it shouldn't be used. I just wanted to demonstrate the wild inaccuracies of a simple measurement system. (cf ISC handicaps in RIOW race!)

PY was, after all, a performance based system too, albeit altered only once a year on the basis of club returns. The PY for cruisers has been abandoned by the RYA as few, if any, returns were being made.

In any case, with NHC, as there are no allowances made (unlike the PY system) for prop, rig, keel, engine, spinnaker, chute etc. then a competitor may do what he likes to the boat... appropriate for each race. Over a series this will even out. If we stuck to an NHC base number, however calculated, with no regular alteration, it would be a huge disadvantage, for instance, to the non spinnaker or three bladed prop guy.

For one off races we hav'n't really any option but to stick to the numbers and allowances we have under PY.

Chris.

Within the 26's alone we have lift and fixed keels, inboard and outboard engines and every type of prop. If we are to race with any chance of a level base we must keep our allowances.