I agree with Josh on contacting Hutch at PYI to get the best info. Your description of being unable to reach full RPM when in gear does sound like a reduction in pitch is called for.
I have changed the pitch on Calypso's MAX Prop several times including the original effort at installation. For a few years I intentionally ran 10% over pitch to reduce cruise speed RPM. Before we went around Vancouver Island (2011) I reduced pitch by one increment to be sure we could achieve full RPM (horsepower) when motoring into bigger waves and higher winds. The reduction to cruise speed (at a smooth engine RPM) was about .2 knot with no measurable change in fuel consumption. The MAX prop owner's manual has the chart that describes the X Y relationship to pitch. I have heard tales of divers willing and able to change the pitch on a classic MAX prop underwater. I would not attempt it myself and in the past set up a deal with a yard to haul and hold in the slings for the change then re-launch. It may take several haul/launch cycles if you want to fully optimize the pitch. Martin Calypso 1971 C&C 43 Seattle [Description: cid:D1BF9853-22F7-47FB-86F2-4115CE0BAF2F] From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Josh Muckley via CnC-List Sent: Sunday, July 27, 2014 9:22 PM To: C&C List; Bill Hoyne Subject: Re: Stus-List Prop Grease (Now Max-Prop settings) Bill, Contact Fred "Hutch" Hutchinson at PYI. He'll be able to tell you immediately where to start. hu...@pyiinc.com<mailto:hu...@pyiinc.com> Josh Muckley S/V Sea Hawk 1989 C&C 37+ Solomons, MD On Jul 28, 2014 12:16 AM, "Bill Hoyne via CnC-List" <cnc-list@cnc-list.com<mailto:cnc-list@cnc-list.com>> wrote: Hi All, I have a Max Prop of unknown diameter (forgot to measure when I had the boat out of the water). I also have a Volvo Penta 2003 and when I run the engine in idle I get 3000+ RPM,s but when I run it in gear I only get 1900-2000 RPM's. I suspect the pitch is a little high. ( A dripless seal, new shaft and cutless bering were installed last year and in the process the max-prop was taken off and may not have been installed with the original specs of which I don't have from the PO.) My question in does anybody out there know what the X,Y values should be for a typical C&C MKII? I would like a starting point to compare what is in the prop now and where I should head to. The other question is can I do thin in the water or do I need to haul the boat? Thanks, Bill Bill Hoyne Mithrandir '74 C&C35 MkII in Victoria,BC
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