Join Date: Mar 2008
Location: outer Cape Cod
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Re: 3-blade fixed prop recommendations?
Regarding pitching issues, it seems from my own experience and what I'm seeing here that some tweaking becomes necessary when going to a CS prop; my original 2-blade was a 12" x 10" and was replaced by a 12" x 6" CS-exactly half the pitch! (I forgot to mention the dia./pitch in my previous post). As it turned out, I still had to have some adjustments made at New England Propeller in Plymouth, as the engine would not go above about 3150 rpm. They (and Norm) recommended against any further reduction in pitch, but simply removed some of the cupping. This solved the problem. While I never had any real problems backing or stopping with the old 2-blade, I notice that she's a lot more surefooted now; the only problem I have with propwalk is when I have a decent breeze pushing against my starboard side, and even then, it's more manageable. It's worth noting here that my Yanmar's Hurth/Kanzaki gear-like that on most small Yanmars-has a higher ratio astern than ahead; ahead it's 2.62:1, going astern it's 3.04:1. Even with the lower shaft speed going astern, this prop pulls its weight without overrevving the engine.
Last edited by Catboatfan; 09-27-2012 at 03:58 PM.