Yanmar Fuel Consumption Table

[Bob Dugan]

Becky and I are taking the Mack-Boring diesel engine course. It is very informative. Here's a chart that shows hourly fuel consumption under way at various RPMs for different engine models. The instructor said that Yanmar is famous for having fuel efficient engines.



bdugan@stepzero.com

[Lou Ostendorff]

Hello Bob;
I appreciate your post and this interesting info...did the course instructor indicate where the most efficient operation (MEO) could be expected, or does this depend on the boat, prop, etc. ? I have generated a speed curve for my CD25D and 1GM10, unfortunately, it's different for different boats so I suspect that my MEO won't be quite the same as yours...however, if you have a CD25D with a 3-blade prop and a 1GM10, the curve should be close. When you finish the course, please post any other info. you think appropriate...thanks a lot!
Lou Ostendorff
CD25D Karma
Hailing Port "Oriental, NC" ('cause I like the name)



louosten@ipass.net

[Bob Dugan]

Hello Bob;
I appreciate your post and this interesting info...did the course instructor indicate where the most efficient operation (MEO) could be expected, or does this depend on the boat, prop, etc. ? I have generated a speed curve for my CD25D and 1GM10, unfortunately, it's different for different boats so I suspect that my MEO won't be quite the same as yours...however, if you have a CD25D with a 3-blade prop and a 1GM10, the curve should be close. When you finish the course, please post any other info. you think appropriate...thanks a lot!
Lou Ostendorff

Lou,

I think I'd like to generate a speed curve for my boat as well. I have a 1GM (not a 1GM10) and a 3 blade prop. How do you do it? Is this something I can read about in Chapman's? The instructor is mostly showing us how to fix the engine when something goes wrong and getting us to the point where we can perform all the routine maintenance on the engine to prevent things from going wrong. His name is Larry Berlin and he's quite a character... he's been teaching this stuff for close to 30 years and has an encyclopediac knowledge of Yanmars.

He said that the Yanmar engines were designed to be run at an RPM of 2500 to 3100 under load. If you take care of the routine maintenance, then the engine will last through 10,000 hours of use.

We've taken Cricket out a couple of times, but we're going to pay more attention to what this RPM range translates to in terms of hull speed.

Speaking of hull speed... what do you see for a cruising speed on your boat under power and under sail? To be conservative we're estimating 5 knots under power and 4 knots under sail. We're trying to use these for trip planning.

Bob
CD25D Cricket #092
Wayland, MA

CD25D Karma
Hailing Port "Oriental, NC" ('cause I like the name)

bdugan@stepzero.com

[Lou Ostendorff]

Bob;
If you search the archives for "25D Speed Curve", you'll see a post I made a year or so ago on this very subject...it's easy to do for your boat, you just need a calm day to log the numbers, and a measured course or GPS to record rate or distance; I plotted speed (Knots) vs. engine RPMs and got a fairly consistent curve until I got close to 6 knots, where things start getting weird since hullspeed on a 25D is about 5.84 Knots. I did another interesting thing after seeing your fuel consumption chart...I plotted, over top of the speed curve, range in nautical miles vs. RPMs for a 25D with a 12 gallon tank. It 'appears' that there are some plateaus in this new curve, for instance, at 1700-1800 RPMs, I 'might' expect close to a 400 NM range...at 2500-2600 RPMs, I 'might' expect a 250 NM range...it then drops rather dramatically around 3500-3600 RPMs to about 125 NM...of course this is all hypothetical since I haven't ever travelled this far at one time before...the key is to start recording points on the graph, and over time, you'll have a more 'reliable indicator' for trip planning...it's great fun too! Let me know how you make out, and good luck!
Lou Ostendorff
CD25D Karma
"Navigare necesse est, vivere non est necesse"



louosten@ipass.net

[Leo MacDonald]

Becky and I are taking the Mack-Boring diesel engine course. It is very informative. Here's a chart that shows hourly fuel consumption under way at various RPMs for different engine models. The instructor said that Yanmar is famous for having fuel efficient engines.

macdoreNOSPAM@aol.com