boat MPG

[Billdc]

Has anyone converted fuel use to MPG? I installed a fuel flow sensor and finally got a chance to use it today. I set the display to MPG on my HDS5 and it seems like my best fuel rate was at 37-38 MPH@37K RPM I was reading 3.25 MPG. I have a 23' bowrider, about 5K lb, with the Volvo 5.7 GXi and duoprop. I am just wondering if this sounds about right compared to other boats of similar design.

 

[bullcity101]

Re: boat MPG

Sounds pretty darn good to me! 23' footer with 350ci. I know my buddies 26 bayliner with the mercruiser 350 averages about 2.3mpg.

 

[rallyart]

Re: boat MPG

That sounds in the normal range. You'll do best at about 1000 rpm where the hull can think it's displacement but what fun is that.
Also, you don't really want to know the MPG because cars are so vastly better it makes boating painful to think about.
If you go to boattest.com you can get some comparative charts.

 

[Philster]

Re: boat MPG

4 - 4.5 MPG @ 40 MPH (3800 rpm) for me, which is considered pretty damn good. I can get it up to 5 or 6 by slowing down.

 

[Mischief Managed]

Re: boat MPG

Has anyone converted fuel use to MPG? I installed a fuel flow sensor and finally got a chance to use it today. I set the display to MPG on my HDS5 and it seems like my best fuel rate was at 37-38 MPH@37K RPM I was reading 3.25 MPG. I have a 23' bowrider, about 5K lb, with the Volvo 5.7 GXi and duoprop. I am just wondering if this sounds about right compared to other boats of similar design.

My 25 footer is about 6000 lbs and gets 2.5 MPG at 3200 RPM/32 MPH. 3.25 is excellent for a 5000 lb boat, but you may want to verify the fuel flow is accurate before you set out on a long journey.

 

[LippCJ7]

Re: boat MPG

You do realize you have a boat right? sometimes I think boats are measured by GPM rather then MPG depending on my need for speed LOL

 

[Philster]

Re: boat MPG

I convert: 10 GPH @ 40 MPH = 4 MPG. In one hour, I travel 40 miles and burn 10 gallons. That is a gallon for every four miles traveled... or... 4 MPG.

GPH is nice to know, but if you are burning 10 GPH you need to know the speed to know the efficiency. 10 GPH @ 20 miles per hour is just 2 MPG.

MPG matters.

 

[Billdc]

Re: boat MPG

You do realize you have a boat right? sometimes I think boats are measured by GPM rather then MPG depending on my need for speed LOL

Yea, I know they use GPH and convert like Phil did, but it is just easier and more to the point for me to use MPG. I am just trying to find that sweet spot. And when I see numbers like 15-18GPH it just makes me think of throwing dollar bills overboard every 30 seconds, and I just can't enjoy myself. I still have to calibrate the fuel flow meter with a few runs and actual fuel used to confirm the mileage but I could not find much online. I looked at boat test and found similar numbers for the same size boat/motor. Thanks for all the help, except for Phil, I had no idea OB's got that kind of mileage.LOL.

 

[Philster]

Re: boat MPG

Sorry, newer direct injection O/B's get really good MPG. :redface:

No chunk of iron back there to lug around. But I don't have a great swim platform, if that helps ya feel better.

 

[bekosh]

Re: boat MPG

Just to make everyone feel better, I get 1.4 MPG with twin carb 350's.

 

[Philster]

Re: boat MPG

Normally, I relish in the misery of others, but...

Since your 700 total cubic inches of fuel hoggin' power just ramps up the demand, the supply side reacts by jacking up the price, so that isn't good. Although, on the bright side (for me anyway) you do your part to ensure the fuel in the tanks at assorted fuel docks is nice 'n' fresh.

 

[airdvr1227]

Re: boat MPG

Amen to that. I was feeling kind of bad about filling my 55 gallon tank when a guy pulled up in Tiara with a 340 gallon tank.

 

[MH Hawker]

Re: boat MPG

I did a little MPG test on mine yesterday and I got 4.5

 

[The Famous Grouse]

Re: boat MPG

This is where I've found a little GPS speedometer app for my Android phone has come in handy. Most of these apps will give you useful data like miles traveled and average speed. They also account for time when you are not in motion, so the average speed is a true moving average representation of actual "under power" time.

Even without a fuel flow meter, I was able to pretty accurately calculate my GPH and MPG by simply starting with a full tank and then refilling to find out how many gallons I've used.

My main concern was working out the safe range with a 10% fuel reserve, but these little apps provide some really useful data and the are more accurate than the in-dash speedometer.

Grouse

 

[bekosh]

Re: boat MPG

Here is a guy that is really doing his part to keep the fuel supplies fresh. 75 gallons per hour, per motor.
I wouldn't want to pay for fuel for this boat, but I sure would love to drive it.