fuel consumption

[rourkeh]

Hoping for some real time info from another owner.
Trying to find info on the fuel burn rate for a 1982 hatt 61 cmy with 1271ti engines.
Any other owners of 61's have that info please.

 

[RonNP]

I have a 63CPMY
Fuel consumption is between 0.7 and 0.8 mpg going at 9 to 10 kts, around 1100 to 1300 rpms with one generator going. Both engines are 12V71TI rated at 673 hp.

 

[Wow57pro]

I have a 63CPMYFuel consumption is between 0.7 and 0.8 mpg going at 9 to 10 kts, around 1100 to 1300 rpms with one generator going. Both engines are 12V71TI rated at 673 hp.

63CPMY with 12-71 TI’s. 40 gph at 1900 rpm and 15 knots.

 

[Wow57pro]

I have a 63CPMYFuel consumption is between 0.7 and 0.8 mpg going at 9 to 10 kts, around 1100 to 1300 rpms with one generator going. Both engines are 12V71TI rated at 673 hp.

63 CMY with 12-71 TI’s. 40 gph at 1900 rpm, 15 kts with one 20 kw running. Numbers from a trip 2 weeks ago, Jupiter to West End.

 

[rourkeh]

That is very encouraging news. I am getting ready to go home to St Maarten from the Dominican Republic where I just bought this boat. I was figuring it would take a lot more fuel to go 360 NM at around 13 knots, say maybe 40gph. From the numbers you guys are quoting it will be a lot less. I do not trust the flowscan system on here as I do not know if it is working correctly.
Thanks a lot for the feedback folks.

 

[Pascal]

13 kts is just about the absolute worst speed you can run pretty much any boat at. Doesn’t mattwr if it’s 50,60, or 80... doesn’t matter if you have 1271, 892s, C32s. 20% above hull speed means 2.5 times more fuel

On a 63, at 13 kts you will burn the same you would at 18kts on plane but going much slower

Throttle back to 9.5 kts and you should burn about 12 to 14gph combined. Do the math compared to 40GPH at 13kte...

 

[SKYCHENEY]

13kts is not the sweet spot. You'll probably find that its either 10kts for slow cruise or push it up on plane at 17kts or so.

 

[Briankinley2004]

This chart is pretty accurate if you go to the "old engines" at the top. I have the same boat and it is reflective of mine. You should get similar results on the 1000 RPM or less. Once you go above hull speed for your boat it will probably vary some from the chart depending on the design. As mentioned about 1300 RPM is probably a bad area to operate in for fuel consumption purposes. Notice 1500 RM vs 2250 is same "MPG" fuel burn yet more than twice the speed. Hell on the engines either way. I prefer to run mine at 1000 rpm's and turn up to 1800 for 20 minutes eery 4-6 hrs.

 

[riverrandy]

Just love this chart!!!

With about 300 more HP, and the 5 blade you have really made some interesting changes. To me the more efficient (Re. less slip) props tell the real story. Original top end of 2200 RPM is what I would see as fast cruise at almost 5 more knots, and a bit more range. So Cool! I am curious why there is so much more slip at lower RPM with five blades?

This better efficiency speaks volumes to ZF's idea to retrofit counter rotational props on the end of straight shaft inboards. Man would that be the bomb...or rather the torpedo

 

[rourkeh]

OK..
So it looks like I am going either 9 knots or 15 knots plus.
Thanks for the fuel chart, excellent information.

 

[doc g]

18 gph at 10knots, 1150 rpm , 650 hp 1271 ti in a heavy (112K) 61 cpmy.10- 10.5 K is the sweet spot for that boat just enough to lift the bow up and keep enough water running over the stabilizer fins to be comfy. I posted a chart years ago here....Pat

 

[Play'N Hooky Too]

View attachment 32585

....

May I ask what is source for this chart? Are they available for other models/ configurations?

Thanks
-Alan

 

[racclarkson@gmail.com]

I have the same boat and motors as Brian. 9.5 knots is my most efficient slow cruise. I can double that speed if I quadruple the burn rate. When do you have to be there?

 

[rourkeh]

No big rush to get home but the weather looks good Monday and Tuesday to get across the Mona Passage. The last time I crossed the Mona I had to go and I got the snot kicked out of me and only made 2.5 knots the whole way. No chance of a repeat.