Posts: 3508
Location: Elk River, Minnesota | And I am sitting here contemplating HOW one could lose RPM in the designed prop, same construction materials in the same pitch and increase speed... The larger fins of a 11-1/4 might reduce prop slip a touch, but to lose 300 RPM's and gain 1 - 2 mph?
I'm no physics professor, but lets saythe original prop had a 15% slip. The new, larger diameter prop would have to have a slip factor of .06% NO stock aluminum prop, nor any aftermarket steel prop could attain a slip factor such as that on a multispecies/walleye/muskie, or even a top end bass boat could get to that point.
Now...lets say the original prop was 20% slip (Quite likely for a stock aluminum)...the larger prop would have to drop to 10%. With a stock yamaha aluminum... Very very doubtful to gain that much without other changes to the boat set-up. Can't say it couldn't happen, but I would say it is highly suspect.
Worrall would know with the Tuffy series as I believe he has helped design many of their model lines, so his suggestion to be mindful of the style of boat and propping accordingly is spot on. What happens on a deep V is quite different than a padded hull.
Steve |
