Here is the update on the post following the error I found in the rating certificate. The yacht is only 12.07 metres long, not 12.7 and I hoped it would make a difference. Hope was a futile emotion as the revised updated rating came through this morning with a revised rating of 1.111. That is a mere one percent reduction and is at odds with my estimate. I don’t have a VPP program but based on engine power required to propel the hull I have calculated a decrease in length of the amount of the revised certificate should have resulted in a three percent reduction in speed and hence rating. This applies right through the speed range which I have modeled with 5, 10, 20 and 30 Hp power available at the engine. I would think that if an increase in waterline length of 630 mm is only going to add 1% to the rating why not go for the longer length. Perhaps that is why all the new fast yachts have plumb stems As I said in the initial post there is no respite in the rating wars as far as Passion X is concerned. Our IRC rating came through and we were rated at 1.122 now revised 1.111 to the same as a First 45. Black Sheep, a First 45, rates 1.108 so we would have to give this 45 footer some time. This is no surprise as the ORCi ratings are similar. We appear to be rated just a little faster than the Sydney 38’s and an A40 which we have a lot of trouble matching. A J133 would have to give us a few seconds but they usually clear out by many minutes. The revised IRC certificate suggests we should have a crew of 10 and all of them on the windward rail. That is about 320 kg more crew than we typically have on board. That is about 16% more righting moment and would be significant but we are not going to find that many crew. The rating does suggest we have yet to find the right groove for Passion X in terms of pointing angle and boat speed.
Revised IRC rating for Passion X
Passion X incorrect IRC certificate