>…2 bladed prop is really that inefficient or my pitch should be changed.<
My experience on OPB (other people’s boats) with 2 bladed MAX props is they are not inefficient. Calypso has a 3 blade mostly to reduce vibration. If I had to replace the prop I would buy a 2 blade MAX prop. > Above that rpm, there is not much of a noticeable change in speed, just > noise.< Does this indicate you can throttle up to max engine rpm easily? If so I would take that as an indication the pitch should be increased. Last time I changed the pitch on Calypso’s 3 blade it seemed I could move in +-10% change increments. Do you have a local boat yard that would give you a deal on a quick haul out, hang in the slings to change the pitch, the re-launch to test? I have read of people changing the pitch in the water but I would not attempt it myself. Maybe a pro dive service has the chops and spare parts to pull it off in shallow water clear enough to find the important piece that dropped to the bottom. Martin DeYoung Calypso 1971 C&C 43 Seattle [Description: Description: cid:D1BF9853-22F7-47FB-86F2-4115CE0BAF2F] From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Ron Ricci via CnC-List Sent: Wednesday, July 22, 2015 6:07 AM To: cnc-list@cnc-list.com Cc: Ron Ricci Subject: Stus-List C&C 37+ Propeller & Boat Speed I’m curious to see what kind of speed everyone gets on their 37/40. It is interesting to see that some listers get over 7 knots. I’m lucky to get 5 knots at 2500 rpm. Above that rpm, there is not much of a noticeable change in speed, just noise. Here’s what Patriot has: · 3HM35F Yanmar 30 HP · 2.14 Gear Ratio · 16” Max-Prop – 2 bladed · Right Rotation – from http://www.pyiinc.com/images/pdf/max-prop/PYI_Max-Prop_2_Blade_Instructions.pdf o 18° o X = E o Y (dot) = H o Y (dot)(dot) = V Perhaps the 2 bladed prop is really that inefficient or my pitch should be changed. Any advice will be appreciated. Regards, Ron Ronald V. Ricci S/V Patriot C&C 37+ Bristol, RI ron.ri...@1968.usna.com<mailto:ron.ri...@1968.usna.com>
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