Well almost nothing! After a lot of hard work from the crew we had Passion X weighted for the IRC rating certificate and for a measured input to the ORCi Club certificate. While the weight on the certificate went up from 4306 kg to 5042 kg the rating came down only 2% from 1.11 to 1.092. The rating was influenced a little by the larger spinnaker which gave a small speed increase in light air running and the removal of the runners which were incorrectly shown on the certificate. It was not until I read the detailed Velocity Prediction Program description that I realized the incorrectly shown runners impacted the rating. That contributed 0.004 to the rating reduction.
So for a lot of effort we have a small rating reduction but still cannot sail to the new rating.
I will probably go for the full International ORCi rating and see if the extra measurements make a significant reduction to the rating.
There was a little good news with the rating reduction but that was off set by the slower top speed potential in the VPP. Our reaching speed in 20 knots of wind is now predicted to be 11.71 knots and not the 12.25 knots we would have had if the yacht had been 700 kg lighter. This speed reduction is pretty much the same as I calculated for the performance under motor with the different weights so I was not surprised with the top speed reduction. What did surprise me was how little the rating came down.
We still have a lot of work to do to sail Passion X to its full potential and we have not yet tried the light air reaching angles suggested on the VPP program. Up to now we have run square the wind while the VPP suggests we should be sailing at gybe angles of 142 degrees true. Hopefully we will soon have the asymmetric spinnaker running from a short bowsprit and will get some excitement from that.