Rebuild the prop. Both blades should open exactly the same. Send it back to Martec. I did that and replaced cutlass bearing on my 34. Smooth as silk afterwards.
On Mon, Nov 11, 2024, 7:35 AM Wyatt via CnC-List <cnc-list@cnc-list.com> wrote: > Make sure to check the integrity of your prop strut after you upgrade/fix > your current prop and verify drivetrain alignment, good luck! > > On Sun, Nov 10, 2024 at 8:40 PM ejwills1993--- via CnC-List < > cnc-list@cnc-list.com> wrote: > >> Hey all - >> >> I have a 30 Mk II with the original Yanmar 2GM20F and factory Martec 15D >> x 11P x 1 2-blade brass prop. About 850 hrs on the engine, seems in great >> shape. >> >> Issue: I can only motor at 2200 RPM before the engine/stern begins to >> vibrate. This puts me at a max cruising speed of 5 kts. >> >> From the survey, one of the prop tips measures about 1/8 inch farther AFT >> (axially) when at 12 o’clock position versus when the other tip is rotated >> to the same 12 o’clock position. The prop blades are not chopped/scraped >> and the prop appears to be otherwise symmetrical in all other dimensions. >> >> The engine does not vibrate when revved to 2800-3000 rpm in neutral. >> >> The shaft does not wobble, and there is no leakage from the shaft packing. >> >> Q: What cruising speed should I expect from this boat and the Little >> Yanmar? I think the spec in the Yanmar manual says cruising rpm should be >> 2700-2800 rpm without breaking a sweat. I’m not expecting to motor at 8-9 >> knots like a big sailboat but I do expect to be closer to the 30-footer >> hull speed of around 6.7 kts. >> >> I’m trying to figure out if this is a valid excuse to get a folding prop >> :) >> >> Thanks! >> >> -Eddie W. >> >
