I replaced the 3 bladed bronze prop on my 28' S2 sailboat with a CDI
PerfectPitch plastic 2 bladed prop and I promised I would report
performance. So far, I can only report on performance under power.
The new prop brings her up to about 6.3 kts easily in calm water. The
last few hundred rpm doesnt seem to give any more speed which seems
consistent with what they say about "overpitching the prop for calm
water to have reserve for rough water". This is as good as my old
bronze 3 blade prop.
They really push the good performance in reverse but oddly I do not
see this. It may not be as good as my old prop but this was never an
issue anyway.
So far, so good, I like it.

David OHara