Rough Estimate of GPH?

[keninaz]

My wife and I would like to purchase a used 20-24' Cuddy or Cabin Cruiser. Typically they seem to have a 5-5.7 L I/O installed in them. We want something we can spend a few nights on board to make the drive to the larger lakes worth it.
Primary use will be on freshwater lakes in AZ for fishing.
What kind of consumption of fuel will I be looking at assuming I stay at a decent speed with the secondaries of the 4 BBL carb not engaged?

 

[thumpar]

A guess for cruising speed (3000-3500RPM) would be 4-7GPH but that is just a guess. 20-24' doesn't sound like a big difference but it is. Some brands are heavier than others too so that will make a difference.

 

[redneck joe]

my old school 23', about 6k loaded gets 3 MPG at about 28 MPH with a 260 5.7 carb'd

 

[keninaz]

Thanks, that is about what I figured assuming the right prop is installed. I learned long ago not to run a boat at top speed unless the wallet is deep.
I had a 23' cuddy years ago with a 5.7 and it was very heavy. I found it was burning about 7-10 GPH with tides and such. Changed the prop and installed adjustable linkage on the 4 BBL rather than vacuum operated that got it down to 3-5 GPH at a decent cruise speed which was well below top speed on that boat.
Hey, at today's prices for fuel it all counts on the retirement budget!

 

[tpenfield]

If you get 3 mpg while cruising at 30 mph (which seems about right), then you would be using 10 gallons per hour while underway. I would think that your overall gph would be around 5 gph, considering trolling, idling, etc.

 

[MH Hawker]

The only way you will know is to fill the tank run at WOT a hour and refill

 

[bruceb58]

The Wellcraft in my sig get''s slightly less than 3MPG at cruise. I have a fuel flow meter integrated into my GPS so I know exactly what I get at all times.

 

[phiny1134]

My 23' cuddy with a 7.4l gets a little less than 3 MPG at cruise, which puts me at around 10 gallons per hour. This site http://www.boat-fuel-economy.com/mercury-mercruiser-3.0-181-fuel-consumption-us-gallons is another resource that will help you get a ball park figure on fuel burn rate for different engines. Of course your mileage may vary. Good luck on your future boating!

 

[keninaz]

TNX for the information. That link is pretty nice too.