Can your SB8 achieve full rated RPM either in calm or choppy conditions? Calypso's 3 blade MAX prop was intentionally over pitched (by 10%) for many years. I did this to allow calm water hull speed at an engine RPM "smooth spot". Worked fine for most PNW inland waters.
For our trip around Vancouver Island I wanted to be sure Calypso could power upwind effectively in all wind/sea conditions. I "down shifted" the prop by 15% (now 5% under pitch). The 20 year old Perkins 4-108 could now run up to full rated RPM (3600) while powering into a wind and sea. I did not observe a significant change in fuel usage but we did choose to use 6.6 to 6.8 knots (down from 7 to 7.2) as our target powering speed through the water. My key point is: If your engine cannot reach full RPM it is not achieving full rated horsepower. The pitch of a prop may be more important than the diameter or number of blades. Martin Calypso 1970 C&C 43 Seattle -----Original Message----- From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Allen White Sent: Wednesday, February 13, 2013 3:38 AM To: cnc-list@cnc-list.com Subject: Re: Stus-List propellers I have a 26 with a single cylinder SB8 that is not able to push the boat to hull speed easily in wind and chop. Has anyone specs on what prop should be on the boat, and any possible upgrades. The current prop is a 2 blade fixed, unsure of the specs. I cruise more than race, and seem to wind up motoring home often when the wind gives up on me. I love the boat and would welcome any advise you guys can offer. Allen C&C 26 Windfall - _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
