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post #7 of Old 11-30-2009
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Originally Posted by KeelHaulin View Post

Did you go from running at lower RPM with the 18x16 to higher RPM with the Campbell Sailer? What boat did you have and what was the engine HP and reduction? That's a huge change in prop pitch in addition to a smaller diameter.

On the Martec props; I have heard about the pins wearing the bronze at the hinges; how long does a Martec prop typically last before the prop needs repair or replacement? Seems that galvanic corrosion and wear due to thrust on those pin holes is inevitable due to the design.
It was a Choate 40, about 17,000 lbs actual, with a 50HP Pathfinder and Hurth V-150 (don't recall the exact reduction but you can look it up I'm sure) What we noticed most about the change was the smoothness, the cruising RPM differed only by a couple of hundred rpm (higher) It's been a few years now but I believe we cruised at 7 knots at around 2400rpm.

On our Martec (non-geared folder) the cheeks into which the blades fit to be pinned had "splayed", opening up a bit allowing extra clearance for some vibration. While we coveted a MAX prop, just couldn't justify the cost for the type of sailing we did then. The Campbell was a good (inexpensive ~$750CDN 10 years ago) compromise.


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