[C320-list] Correct Engine RPM's

[jackbrennan]

On the Yanmar, peak sustained running is 3,200 rpm with a top of 3,600 rpm.

I've seen owners recommend all kinds of numbers, even 3,200, but I think that's way too high.

On longer motoring cruises, I like to range between 2,200 and 2,400 rpm. That gives a speed of roughly 5.5 to 6 knots at half to 3/4s of a gallon.

3,000 might get me to 6.5 knots, but fuel consumption will be way up, probably more than a gallon an hour.
Jack Brennan
Sonas, 1998 Catalina 320
Tierra Verde, Fl.
Dolphin Cruising Club of Tampa Bay





Sent from Yahoo Mail on Android 
 
  On Wed, Jun 12, 2019 at 3:15 PM, Mark Seyler<mseyler at cox.net> wrote:   I've always been told that most diesel engines are happy running at about 70-80% of the rated maximum, or "red line" on the tachometer.  On my Perkins the red line is 3,600 RPM, so I usually run around 2,500 - 2,700 RPM. I don't know the red line for the Yanmar, but the math should be the same.

The other question that may apply is what gives the best fuel economy.  I only run my engine to get in and out of my marina, and don't burn enough diesel to care that much.  But if you are cruising longer distances, that might make a difference.

Mark Seyler
S/V Reality, 
Catalina 320, #232
New Orleans, LA



-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf Of Roger Nitkin
Sent: Wednesday, June 12, 2019 1:14 PM
To: c320-list at lists.catalina320.com
Subject: [C320-list] Correct Engine RPM's

We recently installed a new MaxPropEasy feathering prop to replace the original bronze two-blade prop on Summer Time.The MaxProp supplier pre-set the blade pitch for our Yanmar 3GM30F and boat.

Does anyone have any guidelines on appropriate cruising RPM's, or how we can figure this out ?Thanks !
RogerSummer Time, 1997, #429Westport, CT