280 - 300 Sedan performance data 1991-1993 model

[Dusty Bilges]

I also note that it took 5.2 hours to burn 88 gallons of gas for a sixty-mile trip. That's 17 gph. That's about 12 mph. That's about 1.4 gallons per mile. Seems high, but there was a hell of a headwind coming back which didn't generate any seas as there was not much fetch, but every boat is a sailboat, and we have a lot of exposure. I suppose running with the bow too high or too low didn't help.

[bud37]

If you are saying you were doing 12mph for the trip then you were just pushing water ( engines working hard )....what I mean is that the efficient speed ( hull speed ) for a boat that size would be around 6 mph...then the next efficient spot as far as mpg is concerned is with the boat on plane....maybe around 16 + mph and trimmed out.

You really should see something around 1mpg or just a bit less.Clean bottom and running gear is a given.

[Dusty Bilges]

Thanks, Bud. Actually there were times when I was about six knots going up and down a river which was part of the trip, and times when I was on the open lake going well over 20 knots. You finally gave me the answer I was looking for, to wit, "around 15+ mph" for most efficient speed." This weekend I'll experiment some more. By the way, my boat is on Rainy Lake, and the cruise was through Voyageurs National Park from its westernmost boundary all the way east to where it ends, the Kettle Falls Hotel (formerly a 1903 whorehouse for the lumberjacks) accessible only by boat or seaplane.

[Craig_B]

[Cooler]

Just FYI - I have 350XL Crusaders in my Mariner, with V drives. My most efficient cruise speed is right at 3000RPM, which gives me 18 to 19MPH, and burning 17GPH. If I speed up to 3400RPM, then I burn 24 GPH at 22 to 23 MPH. er

[Dusty Bilges]

Very interesting. Thanks, Cooler. I did the math on your numbers, so at 3,000 rpm it would take 1.2 hours to go 23 miles instead of 1 hour at 3,400 rpms, and you'd burn about four gallons less to get there 12 minutes later and have a little quieter cruise.

[Cooler]

Dusty - I actually burn about 7 gallons less between those 2 rpm levels. I'll take an extra 12 min to get there. It's like earning $2 a minute. er