Mac Mileage Knotage

[ALX357]

Being lake-bound, is my rationale for thinking in land-lubber miles, not even nautical miles.
No matter, I can do a calculation.

Can any MacX owner with a Merc 60 BigFoot 4-stroke motor tell me how many mpg at non-planing cruising speed is attained ? Probably thinking 5mph.

Anyone with the Merc 60 BigFoot 4-stroke on their X ?

[Catigale]

There was just a thread from Quebec on low speed cruising mpg....someone had a complete table of data. It might have been a 70 horse, but at low speed it will be really close to the 50 HP

[Retcoastie]

Stephen wrote;

at low speed it will be really close to the 50 mph

50 MPH -- low speed

Man, don't get in a hurry around me.

Ken

[K9Kampers]

That's gotta be a white hull then, eh!

[mallardjusted]

In case you don't get any bigfoot-specific estimates, I had copied some data from past posts where someone stated they got 7mpg at 7mph with a Honda 50 4-stroke, and someone claimed 11mpg at 7mph with a Suzuki 70 4-stroke.

Wind and current become much bigger issues at the slower speeds, though. Sometimes to the good, other times not!

[Chinook]

On our spring cruise in the Bahamas I kept good track of motoring time, distances, and fuel consumption. We were running a Nissan 50 TLDI, which is regarded as having good fuel efficiency in the low to mid speed range. We motored for a total distance of 800 nautical miles, at average speed of around 5 knots, with engine speeds typically between 2000 and 2500 rpm, and around 2200 rpm most of the time. Fuel usage averaged 6.7 nautical miles per gallon overall.

[Catigale]

I claim autocorrect FAIL!!

(fixed above)

[technicalman]

There was just a thread from Quebec on low speed cruising mpg....someone had a complete table of data. It might have been a 70 horse, but at low speed it will be really close to the 50 mpg

Must have been a Toyota Prius hybrid outboard.

[Phil M]

On our spring cruise in the Bahamas I kept good track of motoring time, distances, and fuel consumption. We were running a Nissan 50 TLDI, which is regarded as having good fuel efficiency in the low to mid speed range. We motored for a total distance of 800 nautical miles, at average speed of around 5 knots, with engine speeds typically between 2000 and 2500 rpm, and around 2200 rpm most of the time. Fuel usage averaged 6.7 nautical miles per gallon overall.

That is approximately 160 hours of motoring.
1) How many gas tanks did you keep on board for such a trip?
2) What kind of daily wind did you not have that you motored 160 hours?

Thanks for the calculation of 6.7 nmpg. I will round that off to 6 for my Honda. With my 12 gallon tank, I could plan for a safe 50 nautical miles of motoring before refuelling. (6 X 12 = 72) Plus I keep a small one-gallon spare gas tank for emergencies.

Phil M

[Chinook]

We carry a pair of 12 gallon gas tanks, plus two 5 gallon plastic jerry cans on a stern platform and a 2 gallon which sits under the steering seat. That 36 gallon capacity gives us more than 200 nm of motoring range. Wind conditions varied considerably, from too windy to be out there to nearly calm. We motored on some of the longer crossings, which ranged from 40nm to 80 nm in length. On many days we enjoyed 10 to 15 knots of steady wind from a favorable angle, which made for some excellent sailing. The decision on whether or not to sail depended on what kind of speed we could sustain, during the longer crossings, since I didn't want to be arriving at a destination late in the day, when it becomes hard to see the coral reefs. We generally sailed whenever the wind strength and direction permitted, and often motor sailed when our speed under sail was insufficient. We ended up logging 300nm under sail for the trip, and 800nm motoring. We ended up using 125 gallons of gas over the course of the cruise.

[Matt19020]

Here is the link from previous post about MPG:
http://www.macgregorsailors.com/forum/v ... =4&t=18671

Bottom chart shows speeds (click pic to enlarge) I hope this helps some

[Ixneigh]

I drove back to my mooring from indian key, about twenty miles against a brisk wind and chop and did it on 2.5 gallons at 5.5 knots. Engines an etec 60. Not bad as far as outboards go.

Ixneigh

[Semper Fi]

2006 26M with 50HP Honda 4-stroke (carb model), three crew, full ballast, loaded for 250 mile ICW cruise from Houma LA to Pensacola FL. These are approximate due to variation in speed and throttle due to traffic, bridges etc.
3500 RPM
8 mph
5MPG
1.7 GPH

We use the 1/3 rule when planning a cruise or passage
1/3 fuel capacity to reach destination
1/3 fuel capacity to return
1/3 reserved for unforseen fuel use (wind, current, unexpected detours etc.)

Semper Fi

[Phil M]

2006 26M with 50HP Honda 4-stroke (carb model), three crew, full ballast, loaded for 250 mile ICW cruise from Houma LA to Pensacola FL. These are approximate due to variation in speed and throttle due to traffic, bridges etc.
3500 RPM
8 mph
5MPG
1.7 GPH

We use the 1/3 rule when planning a cruise or passage
1/3 fuel capacity to reach destination
1/3 fuel capacity to return
1/3 reserved for unforseen fuel use (wind, current, unexpected detours etc.)

Semper Fi

Would 2500 rpm or 3000 rpm not give significantly better gas mileage? Although I vary between 2500-3000 rpm, 3500 may be worth the small decrease in mileage. What is your reasoning with the Honda 50?

Agreed, the 1/3 rule is a good standard to tuck away in the rulebook we keep stored in our memory.

Phil M

[technicalman]

I had no idea how much gas these 50+ hp outboards consumed. Ery informative. v