Mileage results

M

Mike_J

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C Dory Year
2011
C Dory Model
22 Cruiser
Hull Identification Number
CMC22005A1111
Vessel Name
Natural C-lection
Now that I have done a few trips with my CD22 (twin Yamaha 50 HP outboards) I seem to be getting between 3 and 3.5 mpg (actually between 1.25 and 1.55 l/km!) over a few trips. The combine average is 3.3 mpg over 242 km (150 miles)
You can see the trip information on my blog at: http://naturalc-lection.blogspot.ca/
This seems a lot less than the stats reported at http://www.c-dory.com/boats/classic/cruiser-22/ , but I am curious if my results are typical. I have not made an effort to keep to hull speed or anything - basically 90% throttle or so when we wanted to get somewhere and hull speed or less when trolling or sightseeing...
 
Mike,

You're mileage is the same as what I get with twin Yamaha 50's on a Cape Cruiser Venture 23 (a slightly different hull from yours). Twice I have done trips of about 2,000 miles with a very heavily loaded boat traveling in a wide range of weather and water conditions. Speed varied with conditions and whim, but most of my cruising was at 20 - 24 mph. On each trip I used about 600 gallons. My calculated MPG for both trips was 3.3, rounded to the nearest 10th.

If I just want to cruise at hull speed with one engine, I can get double that MPG. If I insist on going WOT, I'll be down on the low side of 3.0. If wind and wave conditions are really bad, all bets are off. I know in Clarence Strait I've been at about 2.0 as I picked my way through bad water.

You can experiment with props, foils, loading, speed and engine trim. There's lots of discussion in various threads. You may find things you can do to slightly increase your mileage, but based on my own real world experience over several years, I think your mileage is certainly in the ballpark.
 
It was precisely one year ago that my wife Betty and I were in the San Juans; we miss it and are envious of your cruising grounds. Also, that was a nice blog.

While we don't have a CD 22, we have her cousin the Marinaut 215. Do you have a fuel flow meter to determine the optimum RPM settings for your engine throttle. We find in our boat, that if we operate at inefficient settings, our fuel efficiency can drop nearly 15 percent or more. Engines usually have an optimum RPM setting for maximum efficiency. Our Honda BF115's optimum is, for example, 3,500 RPM. Other factors for diminished fuel efficiency are wind, tides, seas, and uneven weight distribution -- particularly when too much weight is at the stern. I'm sure CD 22 owners will chime in with relevant information, but in my opinion, that's excellent mileage. My brother-in-law has a 23 foot Parker with a 350 HP engine, and his optimum mileage as shown on the fuel flow meter is 2.2 MPG. Incidentally, the mileage we get for real (total miles divided by number of gallons expended) is approximately 10 - 12 percent less then what is shown on the fuel flow meter.

Rich
 
I have a C22 with twins Honda 40's. They are carburated not fuel injection, and so far we seem to be getting 5.5 mpg , that is smg not kmg.
I run at 4500 as I was told that that was best for my boat.
Jerry
 
As per other discussions on this subject--the data given on the web site or Boat Test.com is a new boat--very light, waxed bottom, little fuel, no water and no extra gear. Weight, Wegiht and Weight, plus bottom paint etc all make a little difference in MPG.

The 3.3 to 3.5 is a fairly normal figure with a boat in cruising configuration. Some of use even do worse at Lake Powell, with loaded boats and the elevation of 3700 feet ( or a little less)
 
Thanks all - wanted to check if I was in "the realistic range".
 
Mike j,

I have twin, carbed, yami 40's and we are pretty close to the same. I am not very good at that kind of tracking because I run over a pretty wide range of throttle. I do not have fuel flow management off the engines or a flow scan but from my calculations I figure about what you are getting. I tend to not use the distance measure as much as the time and go fuel per hour when I calculate. I'm comfortable with about 100 miles between fuel fills, when I have had to stretch it out. I usually carry the bottom half of the tank full for my normal cruising in the home area though. (About had a heart attack, :oops: when I went fishing with a friend and we left the dock with about 5 gal per tank, :shock: and then spent several hours trolling on the kicker, and came back with about 4 gals per tank left.) :mrgreen: :lol: :thup

Harvey
SleepyC :moon

JC_Lately_SleepyC_Flat_Blue_055.highlight.jpg
 
On a cc 23 venture hull We get consistantly 4.2 - 4.4 and more if we slow down this is with a f115 yamaha with 800 hrs 13 by 15 pitch s/s prop this is non cruise ready light boat[/i]
 
I have a C-Dory 22 with twin Yamaha 50s. I was loaded with supplies for a 5 day trip from Kitimat to Butedale, Hiekish Narrows, Kynoch Inlet, Culpepper Lagoon, Klemtu, Alexander Inlet, Bishop Bay back to Kitimat (had to refuel in Klemtu). I was by myself and left with 60 US gallons of fuel and a full water tank and here is what I got:

Used 88 US gallons = 333 liters = 313 nm = 360 statute miles = 580 km
 
Fuel consumption figures for above mentioned trip:

4.09 statute miles/U.S. gallon
3.56 nautical miles/U.S. gallon
1.74 kilometers/liter
 
Thanks Kevin. Your numbers seem a bit better than mine. Perhaps I am too heavily loaded most of the time. usually have at least one other passenger.
 
Mike, looking at your blog maps (which I love) you are spending a lot of time at speed. When you go above hull speed - about 5 knots, you really consume the gas. When I hold mine to 1900 RPM which gives me 4.9-5.5 kts depending on wind & tide, I get about 7 mpg. When I crank it up to 4500 RPM which gives me 17 - 20 kts/h, it drops to the 3 to 3.5 mpg.

From your maps you are doing half to 3/4 of your time at close to 20 kts.

Chuck
 
Thanks Chuck, that is very true. I tend to go WOT to get from A to B and then go slow to fish or sightsee. One of these days I will try to do a trip at under 2000 rpm and see how the mileage is.
Today we had it going at 27 knots, which I am sure used some fuel!
 
If you are careful with trim, limit speed to the high teens/low 20s, and don't bring too much gear, you can get very close to 4 mpg. I get it all the time with my twin honda 45s - not that 4 is anything to shout about.....
 
It is when you think of the big go fast and deep vee hulls for whom the equation is 4gal/mile.
 
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