I do NOT think that TOP one design or Formula racing (on elapsed time) is comparable with large open racing (on handicap).
I also suppose that yr ancient Prindle 18-2 finished 4th place on corrected time and NOT on elapsed time.
Besides I am quite sure that it got one of the top spots ONCE and not in all the open regatta it entered this year. The same for yr Prindle 15.
I remind you that we are speaking about relative performance in a TOP regatta among boats of the same class.
I add a reply to Rolf:
all F18HT but the Eagle have only masts built in carbon. In fact there is no need to use exotic and expensive materials to get to the quite high minimun weight (Kg 130) set by the F18HT class rule. In the past many US and European F18HT owners were in favour to lower it to Kg 120. In such case the use of carbon for the hulls would have been mandatory