You are getting about what you should expect from that engine and boat combination, so the propeller can't be too far away from optimum. Sailboats equipped with Atomic 4s were typically equipped with a 2 blade fixed prop, 12" in diameter by 6" pitch. The relatively shallow pitch as compared to a small diesel is due to the lack of gear reduction in the transmission. All else being equal, a larger diameter is more efficient, but the pitch might have to be reduced to match the torque available from the motor. I have a Gori folding prop on my 27 and I am quite happy with it.
Steve Thomas C&C27 MKIII Port Stanley, ON ---- David Morris via CnC-List <cnc-list@cnc-list.com> wrote: I determined at haulout this weekend our newly-acquired 1975 C&C 30 MKI, Atomic 4, direct drive is equipped with a Gori two-blade folding prop, measuring approx. 11.5". I have neither the experience or expertise to know if this is a great prop for the boat, a lousy one, or, more likely, somewhere in between. After a major tune-up on the engine, we seemed to be able to run at around 6.2 knots in relatively calm water. Any advice, suggestions, observations anyone would care to offer on prop selection would be much appreciated. David J. Morris, MBA President, D.J. Morris & Associates Ltd. 427 Division Street, Kingston, ON Canada K7K 4A8 Tel. 613-531-4429 email: djmor...@djma-ltd.com Member: Professional Writers Association of Canada Blogging at: http://davidmorrisjourneys.wordpress.com/ --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus _______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
