The rule we are trying to apply is that if a boat has completed fewer laps then it can’t be placed
ahead of one who has done more laps
I am far from convinced this is a good idea. Its intrinsic to handicap racing that whenever there is a dramatic change in the conditions during a race some boats will be greatly advantaged over others. One only need consider the pursuit race where the sea breeze comes in part way through the start sequence.
The most obvious anomaly to the casual viewer is the one where two boats of the same class do different numbers of laps, and the one that was ahead corrects out behind. So people want to consider some sort of correction for this because it looks so glaring. But consider the implications.
Ian has already pointed out that your initial suggestion (that no boat with fewer laps beats a boat with more laps, irrespective of handicap) hugely disadvantages the slower boats. The next thing that occurs to people is only to do this sort of correction when boats have the same PY. That seems tempting, until you consider that a few more anomalies creep in. Supposing there was no change in wind conditions, and the boat that did the extra lap spent the extra time upside down retrieving a messy capsize? Supposing two classes are only 1 point different in PY. Supposing 10 points?
The next option is to time the boats on every lap, and if the wind switches off on the last lap go back to the previous lap. That’s more reasonable, but will you also do it if all the boats do the same number of laps and the wind switches off? If not then over the series you are significantly advantaging the faster boats over the slower ones.
If there’s a dramatic change in wind conditions in a race some boats will always be advantaged over others. Its the luck of the draw and we all accept it because there’s nothing practical we can do about it. Yes, the fewer laps anomaly looks particularly glaring, but its only glaring because its easy to spot. If we correct for that one why are we not correcting for all the others which are of equal magnitude, but don’t look so obvious on the race sheet?
I’m of the opinion that its better to let the dice lie as they fall, and minimise the anomalies, obvious and not so obvious, by good race management. Have lots of short laps, not one to three long ones. Know the signs in the weather, shorten course before the big wind change comes in. These are things that will make the racing fairer for everyone, not just those affected by the one that stands out with a casual glance at the race sheet.