At the last club AGM, there was much discussion of local adjustment of national Portsmouth Yardstick Numbers (PN). Whilst there was no specific proposal to vote on, the clear view was that this should be given serious consideration. Accordingly, the committee tasked a working group with finding a recommendation.
It was agreed that any acceptable approach needs to be data-based and applied consistently to all, rather than relying on opinions about individual classes.
Like other clubs, we provide annual returns to the RYA setting out results of handicap racing. RYA provide national PY numbers based on all club returns, updated annually.
RYA then provides club-level data supported by online software. For each class, this gives:
- an estimated PN achieved locally at SSC
- a Confidence Factor (CF) ranging from 0 to1 (or 0% – 100%), based how many times that class appears. The more results, the higher the CF.
These use several years of SSC returns, and thus stable. RYA encourages clubs to use this evidence to adjust PNs, but does not compel this or dictate how their data should be used.
A simple and logical approach (used by some other clubs) is to start with the national PN for each class and then move in the direction of the PN achieved at locally, in proportion to the Confidence Factor.
- For example, suppose a class has a National PN of 1000, and RYA returns show that these boats typically achieved 1100 in local racing (100 points difference).
- If the Confidence Factor is 0.5 (50%) the new local PN would shift by 50 points to 1050 for races in the coming season.
- If the CF is only 0.2, it would shift to 1020.
Further results are shown below. More generally, the formula used is:
Suggested PN = National PN + CF * (Achieved PN – National PN)
The group recommended unanimously that:
- this system should be used for all club handicap racing this year
- it should replace any existing one-off adjustments for specific classes
- all relevant club trophies should be awarded on the basis of these results
- results should also be produced using the standard national PY, so that members can see and understand the effects of this change
- in future, results may be pooled with clubs (e.g. Lancing) that sail in similar waters. This may improve Confidence Factors and will be explored, but meanwhile adjustment as above should proceed.
The main committee agreed that this system be used for all handicap races run by SSC in 2026, including open events (e.g. the Easter series)
SSC returns include results for over 60 (!) different classes. However, most appear infrequently and have a PN Confidence Factor of zero. They will therefore race without PN adjustment.
Just ten classes have non-zero CF (D-Zero, Hadron H2, ILCA 6, ILCA 7, Merlin, Phantom, Aero 7, RS 200, Supernova and Mk 4 Wayfarer). The table below shows how PNs for these are calculated.
Note that a change of (e.g.) 10 points represents roughly 24 secs in a race of 40 minutes.
| Class | National PN (2026) | Past SSC PN achieved | Confidence Factor | SSC PN for 2026 |
| Devoti D-Zero | 1029 | 1049 | 0.16 | 1032 |
| Hadron H2 | 1045 | 1041 | 0.08 | 1045 |
| ILCA 6 / Laser Radial | 1156 | 1166 | 0.12 | 1157 |
| ILCA 7 / Laser | 1103 | 1120 | 0.46 | 1111 |
| Merlin Rocket | 980 | 956 | 0.7 | 963 |
| Phantom | 998 | 1012 | 0.32 | 1002 |
| RS Aero 7 | 1062 | 1083 | 0.04 | 1063 |
| RS200 | 1053 | 1065 | 0.07 | 1054 |
| Supernova | 1075 | 1074 | 0.16 | 1075 |
| Wayfarer Mk 4* | 1107 | 1067 | 0.48 | 1088 |
*Note that SSC previously applied a local handicap of 1080 to the Hartley Mk 4. Any earlier boats racing will continue to use the national PN of 1107.
These numbers are now added formally to our Club SIs in Appendix B