Originally Posted by sunchaser
There are thousands of Cummins 5.9 owners out there that are quite content to run their engines at 1500 or 1800 RPM. They do this day and night for tens of thousands of hours running at a continuous 110 or 130 or so HP. They are called gensets.
Fuel burn on these 5.9 units is about 5 to 6 gph. So here is my question Baltic, do you see any harm in running your engine at it's prime design range (provided oil and water temps are OK) of 1500 to 1800 RPM for long periods other than it results in a slow boat.
I almost time i run 850-1350rmp of my tug (load 30% in that rmp area) qsb works fine and the heat remains normal
This yars I cruised 2580nm, from time to time about 50nm i run fast 6 months period ...
Here in Finland fuel costs US $ 5.8 / gallon and slowly driving I can run at 6-5 nm / gal vs. 12-15kn 1.15 nm / gal, one of the reasons why I bought NT was the ultimate fuel economy vs. the boat size.
If runs quickly i drive that 80% charge for about 15kn, because of the same liters / nm for a period of 12-15 kn.
(sory my bad English)