Re: [omc-boats] Gas consumption

From: lib1@...
Date: Wed, 17 Aug 2005 03:16:02 -0600

Hi Scott,

This is a timely question as so many factors can affect a boat's fuel consumption. We saw gas selling for $3.49 a gallon for 91 Octane at the marina last weekend. But in the greater scheme of our family's annual fuel budget, boating is a drop in the bucket. Just remember, as the EPA folks are so fond of saying, "your mileage may vary."

I'm going to throw out a rough estimate that I've observed is true for my 16-ft I/O boat and see if others agree. I don't have a FloScan fuel flow meter, so this is just from observational experience. Down on Lake Powell it's not too difficult to be over 100 miles away from the nearest marina, so I've keep a pretty close eye on fuel management.

In a typical, stop-and-go, day of skiing, crusing, docking, trolling we take about 6 hrs to go through 16-gallons. But based on an economical, steady-state cruise, in average "smooth" water, of say 25 mph, where she's "on plane," but not turning too many RPM; my boat goes thru about 16 gallons in give-or-take 4 hours. That means an estimated range of "about" 100 miles, or 4 gph, or 6.25 mpg. My guess is the 6 mpg figure would be fairly average across the OMC boat line for "crusing" speeds. The only factory data I could come across was the 1970 Evinrude catalog, which quoted a "cruising range" of 144 miles on the 24-gallon tank of the economical 120 Sport Fisherman, (which was based on the 19-ft Rogue hull).

Not so surprisingly, my 307 Chevy V8 is getting better fuel mileage than my Buick V6 did, because it is typically turning 25% less RPM for a given speed. The torque of the V8 can "loaf" along at 2750 RPM where the V6 was buzzin' @... 3600 RPM. And rpm's are the enemy of good fuel economy. My guess is if you measured the fuel consumption at close to WOT it would more than double the fuel consumed, meaning your range would drop to about 60 miles and you'd go through 10 gph or less than 4 mpg.

BTW, if you really want to know the low-down on what fuel is going through your tank; the CruzPro people make a really nifty, programmable fuel guage, as an alternative to fuel flow meters. It has the following abilities:

Fuel Remaining
Trip Fuel Used
Total Fuel Used (Required to fill the tank)
Fuel Consumption Rate
Time to Go (before you run out of fuel)
Alarms: Settable Low and High


Lee Shuster
Salt Lake City

  ----- Original Message -----
  From: Scott E. Veazie
  To: omc-boats@...
  Sent: Tuesday, August 16, 2005 10:22 PM
  Subject: [omc-boats] Gas consumption

  I was wondering if anyone keeps track of their gas consumption at certain speeds (cruising at 20mph) and the gallons per hour consumption. I haven't really paid much attention, any one else checked theirs?


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Received on Wednesday, 17 August 2005

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