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OT- Gas milage estimates on 23 foot center console boat ?

Milacron

Milacron

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Dec 15, 2000
Location
SC, USA
I'm talking moderate vee hull, not deep vee. Sort of a "bay boat" rather than "offshore" style...about 2,500 lbs without the motor. Powered by low hour 2005 vintage 150 HP Honda 4 stroke outboard. Some extra wind resistance from T Top.

Now don't gimme this "gallons per hour" and "it depends" BS cuz I'm about to specify the "it depends" part ;)..... calm seas, slack tide, and at cruising RPM. So, given all that...best case MPG ?

(ok, ok STATUTE miles and USA gallons ! Now, who will be the first to start yakking about prop pitch and outboard trim and how clean the bottom is and ... )
 
Milacron said:
I'm talking moderate vee hull, not deep vee. Sort of a "bay boat" rather than "offshore" style...about 2,500 lbs without the motor. Powered by low hour 2005 vintage 150 HP Honda 4 stroke outboard. Some extra wind resistance from T Top.

Now don't gimme this "gallons per hour" and "it depends" BS cuz I'm about to specify the "it depends" part ;)..... calm seas, slack tide, and at cruising RPM. So, given all that...best case MPG ?

(ok, ok STATUTE miles and USA gallons ! Now, who will be the first to start yakking about prop pitch and outboard trim and how clean the bottom is and ... )
Click to expand...

You probably need to restate that to GPM (US gallons per mile).
 
gas miles

Oooh Milicron; the natives are getting snarky aren't they? :<) BTW, why a T-Top? Over here, a soft-top is necessary due to the moisture we receive. Wayne.
 
Best case guesstimate based on experience with a 24ft CC/ 150hp and a
19ft bass boat/150hp would be approx. 4 mpg. Wow, so thats a dollar a mile to ride.



On this topic. I know a 4 stroke is quieter, but is it any more efficient?
 
JL Sargent said:
On this topic. I know a 4 stroke is quieter, but is it any more efficient?
Click to expand...
Actually a 4 stroke outboard engine is not quieter...except at idle speeds. It produces a more "pleasant" sound that "seems" quieter...but if measured with decibel meter the level is about the same with either.
 
Sorry Milacron, your scrupulous abhorrance of complications will not simplify your sistuation. Trim, hullform, sea state, load, prop pitch etc are all vital considerations in estimating fuel economy. In fact stating fuel economy in a boat or a plane without specifying operating conditions is almost meaningless.

The Honda 4 stroke outboard is a plus as is the relatively light weight, but what is cruising speed? For about with maybe a 20 ft water line length operating in diplacement speed (not on plane) you milage may be a trifle poorer than when in moderate plane. Generally the thrust needed to drive a boat goes up exponentially with speed but there are bumps and hollows in the curve.

Yes, I know you want a simple answer but there isn't one. I doubt if three owers of identical boats will get the same fuel economy for the same trip over the same conditions. The problem as you pose it is plain indetermnate.

I would hazard a guess of 5 to 7 miles per gallon at moderate planing speeds of maybe 15 statuate MPH but you might get quite a bit more or less because of the nasty conditions you insist we neglect.

On the other hand you can row and get better rmilage than that.
 
Forrest Addy said:
Sorry Milacron, your scrupulous abhorrance of complications will not simplify your sistuation. Trim, hullform, sea state, load, prop pitch etc are all vital considerations in estimating fuel economy. In fact stating fuel economy in a boat or a plane without specifying operating conditions is almost meaningless.

The Honda 4 stroke outboard is a plus as is the relatively light weight, but what is cruising speed? For about with maybe a 20 ft water line length operating in diplacement speed (not on plane) you milage may be a trifle poorer than when in moderate plane. Generally the thrust needed to drive a boat goes up exponentially with speed but there are bumps and hollows in the curve.

Yes, I know you want a simple answer but there isn't one. I doubt if three owers of identical boats will get the same fuel economy for the same trip over the same conditions. The problem as you pose it is plain indetermnate.
Click to expand...
As there are thousands of boats out there identical, or nearly so, to the one I described, there actually is a simple answer to this question. And having owned many boats over the years from 17 to 40 feet, I've experienced relatively stable mpg figures, so it its an easily "known" figure if you happen to have a boat like that already. Which is what I'm after..not "theoretical" MPG but simply what some others with similar boats/outboards have actually experienced.

Cruising speed does not need to be precisely defined, as it is simply the most efficient speed when you are on plane (assuming a planing hull of course)...whatever that turns out to be.

But I've never owned a moderate Vee this length with 4 stroke outboard, so just curious how much better on gas it might be than previous 23 deep vee with 2 stroke outboard. (Which got 2.4 mpg under conditions described) But of course you couldn't resist the opportunity to "show us what you know" even if it's of zero informative help in this case :rolleyes5:
 
Almost the Naked Truth
By JAMES S. COLLINS. The Washington Post (1877-1954). Washington, D.C.: Mar 6, 1929. p. 15 (1 page):
His attitude recalls the advice of J. Pierpont Morgan, the elder, once gave a friend who told him he was thinking of buying a yacht.
"I am wondering if I can afford a yacht," he told Morgan. "How much would it cost to maintain one?"
"No man who asks himself that question can afford to own a yacht," replied the master of the Corsair.
 
Milacron:
The Honda engine will get you 6-7 MPG on the boat you described - at the rpms you intend to cruise. I worked at a marina two summers and the Honda engines won my vote as the most economical and most reliable.
 
"As there are thousands of boats out there identical, or nearly so, to the one I described, there actually is a simple answer to this question. And having owned many boats over the years from 17 to 40 feet, I've experienced relatively stable mpg figures, so it its an easily "known" figure if you happen to have a boat like that already. Which is what I'm after..not "theoretical" MPG but simply what some others with similar boats/outboards have actually experienced.

Cruising speed does not need to be precisely defined, as it is simply the most efficient speed when you are on plane (assuming a planing hull of course)...whatever that turns out to be.

But I've never owned a moderate Vee this length with 4 stroke outboard, so just curious how much better on gas it might be than previous 23 deep vee with 2 stroke outboard. (Which got 2.4 mpg under conditions described) But of course you couldn't resist the opportunity to "show us what you know" even if it's of zero informative help in this case :rolleyes5:"

So why did you even post if you already knew the answer? It's well known that four cycle engines have better fuel economy than two cycle other things being equal so that should tell you something. Also, there's not that much difference in hydrodynamic drag and windage between deep V and shallow V hull forms so fuel economy of one would would be withn a close order of magnitude of the other. Surely a man of your confidence could extrapolate the needed data from his experence without setting epistomoplogical traps for those who desire only to be helpful :ack2: :willy_nilly: :crazy: :toetap: :Yawn: :rolleyes5: :D.
 
Forrest Addy said:
" So why did you even post if you already knew the answer? It's well known that four cycle engines have better fuel economy than two cycle other things being equal so that should tell you something. Also, there's not that much difference in hydrodynamic drag and windage between deep V and shallow V hull forms so fuel economy of one would would be withn a close order of magnitude of the other. Surely a man of your confidence could extrapolate the needed data from his experence without setting epistomoplogical traps for those who desire only to be helpful
Click to expand...

1. I posted because, while I had some idea of what the mpg might be, I wanted to hear from those with actual experience to see what their figure actually was in the real world. FWIW, before I posted I would have guessed about 4-5 mpg, close to what Sea Farmer predicted. But I'm now hoping stuball is correct ! ;)

2. Re "well known 4 cycles better fuel econmony"...uh, yes of course...which is why I want to know what it is ! Can't believe the advertising hype ya know.

3. Re deep V vs shallow V getting simiilar mpg.... well, that's just flat out wrong in my experience.
 
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