28TE fuel usage

[Cape Codder]

I need to chart my rpm's and speed.
My prop must be far different.

2800 rpm, I'm running 16-17 knots, and at 3000, I'm running somewhere around 21 kts.

3200 rpm around 23-24 kts if memory serves me correctly.

[fairtide]

Thanks, mhanna, for the fuel burn information on your Yanmar engine. I printed the graphic material for future reference. It will be interesting to compare your experience with the data published by Mack Boring. While we are talking about fuel, the engine manual states that the cetane rating should be at least 45. Has anyone seen anything higher than a rating of 40 where they buy diesel?

[Maye Marie]

Mariner,
Thank you for your help in posting.

Incase any one finds this of any help these are the performance charts I have made up for Maye Marie.

[mhanna]

Terry our fuel usage vs rpm are off by 5-10%. The reason I ask is I will use yours if you have better data. I took my info from

http://www.yanmarmarine.com/products/product_lp.php



and had to literally 'read between the lines' to get rpm vs gph. I know there will be deltas with wind, weight and "barnacles" ...might as well get as close as possible with the static info.

Anyone have flowscan data for RPMs to verify ?

Matt

[Maye Marie]

Matt,
I am like you still adjusting my information as I run my boat this year. I have made a lot of runs this year in the six hour range and feel this is coming out pretty close in the 3000 RPM to the 3600 RPM range. I went thru the same interpolation as you and found it to be difficult. I enlarged the chart and used a drafting divider to come up with my numbers. I then have been tweaking them a little.

I have read on other threads like boat diesel .com that Yanmars numbers are pretty close. It is definitely a good starting point.

I am with you and would like to see some numbers come off the flow gauges.

I thought the same thing with the speeds you posted I think your on the conservative side compared to what I have been producing. But for now better to lean that way than the other if your cutting fuel close. I have been making some long Tuna runs and am very pleased with fuel burn.

I have the engine box so could be some difference there. I have been told the engine box models are a little more efficient with the numbers. But I think the juries still out.

[driftaway]

Gang,

Just ran a 2003 TE with 315 Y (80hrs at start) from NY to Norfolk then ICW to FL...
2 people + live aboard equipment/provisioning, full to 1/2 tank...
3000 rpm @ 13 to 14 knts with app 2 nm/gal, mostly flat or light chop
one day running 3200 rpm @ 17 knts with about 1.5 nm/gal

driftaway

[jcollins]

Did you run outside to Norfolk or down the Chesapeake?
What was your total trip time? (days and engine hours)
How many miles?
How many gallons of fuel?
Did you diary the trip? Would love to read about it.