miles per gallon question

[loghomer]

I own a 1976 24 ft Searay SRV,350 chevy engine, 255 hp merc. Boat weight is about 4000 lbs. Motor runs really good. However, I believe that I am getting only about 2 miles per gallon in 2-3 ft waves. Does this seam normal?? The trim tabs are up!!!Avg persons on board is 3-4.Any advice or ideas...Thanks Paul

 

[kayakndave]

Re: miles per gallon question

Sounds about right to me.....Boats are terrible on fuel economy. They have to work a hell of a lot harder than even the hardest driven automobile. It's the price we have to pay to have our toys...!

 

[beezee28]

Re: miles per gallon question

loghomer, that seems like half a gallon for 1 mile. Something not right...

 

[qystan]

Re: miles per gallon question

Loghomer<br /><br />I get about 2.4 miles (not Nautical Miles) to a gallon on my 24 ft Trophy (clocked with GPS and flowmeter) running at 24 Kts. This is the 'best' speed for the hull.<br /><br />As Kayakndave say, boats are not efficient. The noise you hear, the wake you create and wind in your hair are all produced by the engine and none of them goes into getting you moving. Cars don't have to create a wake.<br /><br />One thing is that drag is the greatest consumer of power (read as energy=fuel). In the drag equation it rises as a square of speed. Means if you double the speed, the drag goes up four time, triple it and it goes up 9 times. Moderating cruise speeds will go a long way for fuel economy, not to mention engine and parts wear.<br /><br />To provide some feel, in my boat, I get the following:<br /><br />24kts 11.5 Gal/hr Best speed <br />29kts 28 Gal/hr

 

[John Carpenter]

Re: miles per gallon question

In a very similar setup running on glass smooth water I got almost 3 mpg on a 220 mi. trip. I would say that what you are seeing is pretty normal for the conditions you describe. I ran that trip at about 3200 rpm for what it's worth.

 

[record hunter]

Re: miles per gallon question

have a 24ft 6 inch sea ray and burn 3 gallons an hour 305 chevy

 

[Scaaty]

Re: miles per gallon question

77 GM350 24' 5000lb Bayliner. 7 gals/hour at around 2400 rpm with all the people tossed overboard along with the junk that is stuffed in every corner and the hull clean! Miles per gallon is useless...tides in Puget Sound sometimes would have minus miles per gallon. Planes and boats use gallons per hour. Reason? Gallons per hour would be more of a constant regardless of waves, current, and the 87,000 barnacles hitching a ride. And the perfect oxymoron is boats and fuel economy! Stuff a big boat with people, junk, waves, and WOT will get ya 1/2 mile per gallon.

 

[Crazy]

Re: miles per gallon question

Ya I have a 22foot SRV SeaRay 351 ford 4 bbl at 25 mph calm to a little chop get's about 3.5 mpg . I tested it with a 6 gal portable gas tank ... unhooked the main fuel line and hooked up the 6 gal tank , and with my gps I know how many miles I went on 6 gal .

 

[rodbolt]

Re: miles per gallon question

ohhh I love it<br /> its like a custopmer complaing about the fuel bill for 3 225 mercs.<br /> boats eat fuel. not much to do other than keep it tuned,keep the bottom clean and the prop dressed. get rid of excess weight.<br /> my poor old boat just runs. it idles or turns 48-53 hundred anywhere I go. i just fill the tanks as they empty. if I checked the economy it would bum me out <br /> good luck and keep posting