Join Date: Sep 2004
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harmonics vs vibration prop issue
Have been going around and around re: replacing my three blade fixed prop with a 2 blade feathering max prop. Boat: Endeavour 32 with a new Volvo 30 (28hp). Yard found and repaired problems re: cutlass bearing, shaft, shaft dripless seal, and engine installation/alignment. Final decree: engine can rev to 3000 (rated 2800 to 3200) and achieve 6 knots in flat water. Vibration I feel is excessive above 2000 rpm is harmonics, not vibration and the engine in not moving on the mounts. Per manufacturer, I'll sea trial with the distributor and he'll show me that the feeling I'm getting may acceptable. I plan to race the boat so they both say stay with 2 blade, but I strongly think I'll ask to return and replace with their 3 blade. They say a 2 blade will always cause more harmonics/vibration and it should be acceptable in exchange for going faster under sail.