Technology and Operations
This forum is for discussing technological & operational matters pertaining to U-boats.
Re: U-boat diesel fuel consumption
Posted by:
Fritz Steiner
()
Date: November 08, 2007 05:31PM
Just found this site. Jukka, if you're trying to find a fuel consumption figure with the precision you've put on it, I'm afraid you won't succeed. In a laboratory with carefully measured fuel consumption at a specific load you might get a figure, but in actual application you'll never do it.
I was a US Navy diesel-electric submarine officer and twice served 15-momth tours of duty as Engineer Officer. I had Fairbanks-Morse 38D-8-1/8 diesels on the first boat and GM-248A diesels on the other. We used a fuel consumption rule of thumb which was "70/80/90." That meant 70 US gallons per hour at 80 percent load d 90 percent engine RPM. It worked just fine because that's the way we usually ran the engines on propusion.
For what it's worth, the F-Ms were much better engines than the GMs. It was virtually impossible to overload an FM. On the other hand the Jimmys were very sensitive and had to be loaded carefully, or they'd drop the load. In maneuvering situations where it was necessary to go from "Ahead" to "All Back Full" in a hurry that wasn't a desirable quality.
They were both rated at 1,600 HP, but the Jimmys were overrated, probably for wartime public relations reasons. Moms didn't want to think that their boys would go to war with engines that didn't have identical ratings.
I was a US Navy diesel-electric submarine officer and twice served 15-momth tours of duty as Engineer Officer. I had Fairbanks-Morse 38D-8-1/8 diesels on the first boat and GM-248A diesels on the other. We used a fuel consumption rule of thumb which was "70/80/90." That meant 70 US gallons per hour at 80 percent load d 90 percent engine RPM. It worked just fine because that's the way we usually ran the engines on propusion.
For what it's worth, the F-Ms were much better engines than the GMs. It was virtually impossible to overload an FM. On the other hand the Jimmys were very sensitive and had to be loaded carefully, or they'd drop the load. In maneuvering situations where it was necessary to go from "Ahead" to "All Back Full" in a hurry that wasn't a desirable quality.
They were both rated at 1,600 HP, but the Jimmys were overrated, probably for wartime public relations reasons. Moms didn't want to think that their boys would go to war with engines that didn't have identical ratings.
