24' - 28' Best Range Fuel Economy
- Thread starter cymru
- Start date
trophywife
Crew Member
I can run 11gph at 24 mph in my boat=300 zuki on 26 aluminium and that is great mileage as far a outboards gasser.. My honda 225 was 12.5 at 24...
my buddy darren in a grady 25 with a 300 yanmar burns 7.5-8 gph at 24 mph cruze..
my buddy darren in a grady 25 with a 300 yanmar burns 7.5-8 gph at 24 mph cruze..
How about this puzzle...
Boat A is a displacement hull diesel and gets, what most would regard as good fuel economy, let's say 5 GPH at 10 knots, while Boat B uses gas, is not displacement and burns gas at twice the rate, 10 GPH, but at 20 knots. So, take both boats on a 100 nautical mile run, Boat A uses 50 gallons and Boat B uses 50 gallons. They get the same fuel economy! Also, Boat B is less able to out run a storm.
Boat A is a displacement hull diesel and gets, what most would regard as good fuel economy, let's say 5 GPH at 10 knots, while Boat B uses gas, is not displacement and burns gas at twice the rate, 10 GPH, but at 20 knots. So, take both boats on a 100 nautical mile run, Boat A uses 50 gallons and Boat B uses 50 gallons. They get the same fuel economy! Also, Boat B is less able to out run a storm.
Saxe Point
Well-Known Member
Your puzzle perfectly illustrates that GPH doesn't say anything about economy, unless you also talk about speed and distance. Miles (or nautical miles) per gallon is what you want to know if fuel economy is the question. Some displacement hulls will get you great mileage, like 8 MPG. A typical heavy deep V hull in the 20-25 foot range, a Grady White for example, will often be in the 2 or less MPG range. Similar sized aluminums, but still deep V's will do a little better. Less deadrise and weight (Arima, C Dory, Tolman Skiff) will give dramatic improvements and get you 4 MPG or slightly more, which for planing hulls of 20 feet or so is considered excellent. These are gas numbers; diesel will be better.
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daddystoy
Well-Known Member
Just to add to what Saxe Point said is that you have to add speed into the equation as well. Like Cymru's puzzle says, you need to know speed as well to make all things equal. MPG at what speed? If you get great distance and fuel burn at a low speed it is going to take you longer to go the same distance as a boat travelling faster burning more fuel, meaning you are going to burn more fuel to go the same distance. So what is the total fuel burn? And yes, if you can go the same distance in half the time (maybe with a similar fuel burn) I'll take that any day! Oh yeah and for what its worth even a gas guzzler gets decent fuel burn at idle, like was mentioned put the hammer down and look out!!
Magspec
Member
Yep i nmea'd our honda 225 into gps so i can find that sweet spot (fuel economy, engine temp, etc) but havent got it on a good run yet will know better next year when we scoot across great slave lake and head out to the west coast. But i think defiently worth the price having all the info on gps screen if you have a system that can do it.
Gray Escape
Member
Our 26' foot boat weighs 7600lb dry, powered by a 496 MAG 375 hp Mercruiser with duo-prop.
Cruises at 26 knots (30 mph) at 3500rpm, burning 15 gph.
Translates to 2 mpg or 1.86 nmpg.
Could do somewhat better with a diesel driveline, (approx 11-12 gph), however at a premium of approx $20-30K.
Well worth the savings on a commercial boat but hardly worth the premium on a recreational sport fisher in my opinion, especially when diesel is now priced higher than Premium gas.
My 496 can run on 87 octane.
Nice get up and go when you need it too, especially off shore WCVI.
Cruises at 26 knots (30 mph) at 3500rpm, burning 15 gph.
Translates to 2 mpg or 1.86 nmpg.
Could do somewhat better with a diesel driveline, (approx 11-12 gph), however at a premium of approx $20-30K.
Well worth the savings on a commercial boat but hardly worth the premium on a recreational sport fisher in my opinion, especially when diesel is now priced higher than Premium gas.
My 496 can run on 87 octane.
Nice get up and go when you need it too, especially off shore WCVI.
J-GLOBAL
Well-Known Member
I'm not sure this is correct. At GPH it is correct, but at MPG it doesn't matter, the only difference is the amount of time to get there (not the amount of fuel burned).
At 2 Miles per Gallon at any speed, no matter how fast you burn that gallon and traverse those two miles, you have still burnt a gallon and gone 2 miles.
My Kingfisher 2825 with Yamaha 350 according to the gauge the best I can do on plane is 2.3 MPG at around 28 KPH. Moving up to 40KPH the MPG drops to about 1.1.
Right, in either case, GPH or MPG, what is essential to know is the speed. Speed is crucial to the equation!
So, is it right to assume that--to make a big generalization--it is not good to have a super low GPH or a high MPG, since this means a low speed; instead it is best to have a moderate GPH or MPG and a decent speed.
Red Monster
Well-Known Member
The first two numbers are the most important: 6 GPH @ about 14mph = 2.3 MPG
In two hours you would burn 12 gallons and the rate would remain 2.3 MPG
If you want to save money, you travel at the speed that provides the highest MPG.
The math is simple. The units can get a bit complicated.
Is that an imperial gallon or a US gallon? Maybe we should use lites?
Knots or miles?
MPG or GPM?
In two hours you would burn 12 gallons and the rate would remain 2.3 MPG
If you want to save money, you travel at the speed that provides the highest MPG.
The math is simple. The units can get a bit complicated.
Is that an imperial gallon or a US gallon? Maybe we should use lites?
Knots or miles?
MPG or GPM?
Sr SQ
Well-Known Member
2.8mpg......you suck
I would kill to see those numbers
With my 200 optis on my 24 searay 2.1mpg is the best Ive seen so far but I am still trying different props.
Saxe Point
Well-Known Member
Double your mileage with one of these: http://www.glacierboats.com
Aces
Well-Known Member
2.8mpg......you suck
I would kill to see those numbers
With my 200 optis on my 24 searay 2.1mpg is the best Ive seen so far but I am still trying different props.
Those 135's are the only 3 star V6 2 stroke outboards that Mercury produces i believe. That boat gets 15% better mileage than the Grady Gulfstream with twin 150's that i used to own. I tried 4 different prop setups before i ended up with the 4 blades. I forget what the pitch is and my boat is in Port right now so i can't check. I run at 3900 rpm to get my max performance.
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