It is not an exact science, IIRC power boaters will use loaner props and swap them around to find the best one. It is very hard on a diesel to not be able to hit the factory spec max RPMs, gasoline engines tolerate this much better.
Joe Coquina From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of Joel Aronson via CnC-List Sent: Monday, December 18, 2017 12:45 PM To: cnc-list@cnc-list.com Cc: Joel Aronson <joel.aron...@gmail.com> Subject: Re: Stus-List PROPELLER PITCH Richard My MaxProp was set to 14 degrees. Gear ration was 2.6:1 Joel On Mon, Dec 18, 2017 at 11:24 AM, Dennis C. via CnC-List <cnc-list@cnc-list.com<mailto:cnc-list@cnc-list.com>> wrote: Take prop manufacturers recommendations with a grain of salt. Years ago I requested a recommendation from Flexofold. The rep at the time was Chuck Angle who was highly regarded. He said he didn't have a good prop recommendation for my 35-1. :) I went with Martec. In 2011, I repeated the request and got a recommendation for a 15 x 12. In 2016, I again asked and they said 16 x 12. Currently, Touche' is swinging a 14 x 14 Martec which seems a bit under pitched (or too small a diameter). I can run at 6.4-6.5 knots at cruise rpm (80% max, 2450 rpm) and flat water, no wind. On my list for next year's haul out is to measure and document (photograph) the prop tip clearance distance. I will also measure the hub and swing pin location. The swing plane for different props varies. I think prop selection is part science, part art and a bit of voodoo. Dennis C. Touche' 35-1 #83 Mandeville, LA
_______________________________________________ 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
