I have the Campbell 3 blade
Rob, I have had a 3 blade 12X7 Campbell on my CS 27 (27 ft., 6100#, 8 HP Yanmar YSE8) for two seasons. Replaced a fixed 2 blade 13X8.I got it to fix two complaints: 1) Not enough power into waves and wind, and 2) bad prop walk in reverse. There is less prop walk but its still there. As for power, there was a definite improvement. Going out the harbour entrance into a head wind and waves use to slow the boat down to about 2 knots, now I can go out at 4 to 4.5 knots with some throttle to spare. Note, I don't have a tach so I can't supply before and after rpm comparisions. Motoring in calm conditions improved by 1 knot, but I think I may be too conservative with my rpms and could probably motor a little faster. Have not noticed any reduction in sailing speed. Here is my only complaint. The finish on the prop was a bit rough. There are a lot grove marks on the blade surfaces left from the machining/polishing. This lets the algae get a good hold on the prop and it builds up more than my smoother two blade. You may want to talk to North by West to see if they have improved on this. I know two other boat owner who are very happy with the improved motoring performance.Kevin