366 fuel consumption

[Pcmcguire]

Getting ready to move new to me 366 with Volvo penta 8.1s. Can anyone give me fuel consumption rates and most fuel efficient operating speed?

[bud37]

Have a look at this.....not far off imo....just play with it a bit.

https://www.boat-fuel-economy.com/volvo ... us-gallons

[Pcmcguire]

So 34gph per engine or 68gph. That does seem about right at WOT but hoping to get some feedback on rates at less than full throttle.

[Cooler]

Click on the engine list, and the tach will show various RPM stops. Might be a little conservative for a 366, but reasonbly close. er

[bud37]

Fred please delete this, not sure what happened with this.

[bud37]

Source of the post So 34gph per engine or 68gph. That does seem about right at WOT but hoping to get some feedback on rates at less than full throttle.

It is interactive.
Just click on the plus or minus under the tach and you can go up or down a few hundred rpm at a time....it shows gph in the window for one engine...make sure to pick your HP engine first.

[buster53]

I have a 356 with 8.1 Crusaders, so very close to what you have. Wish I had hard numbers to give you but I don’t…only have a feel for it. If you want long range cruising, hull speed or less, so in the 7 to 7-1/2 knot range, will give you close to double the range over18-20 knots. I find running in the 3000-3100 RPM range to be a very comfortable speed and economy, about 18-19 knots and it is just a guess on my part, but I think I am getting a little less than 1 mpg, maybe .8 MPG. This is of course, assuming you have a nice clean bottom and running gear. Doesn’t take much growth to mess with those numbers.

[Alanna Mo Cree]

I made a chart based on https://www.boat-fuel-economy.com/new/v ... nta-375-hp and the actual speeds I was seeing on my 360. The range and endurance numbers are based on 75% of 280 gallons. None of the numbers account for generator usage. This is the raw data I captured:

Code: Select all

RPM    GPH   Speed  MPG  Range  End.
 600   2.16   3.2   1.5   311   97
1000   4      5.7   1.4   299   53
1500   6.8    7.4   1.1   229   31
2000  13.4    9.2   0.7   144   16
2500  20.6   11.2   0.5   114   10
3000  23     17.4   0.8   159    9
3500  29.4   24     0.8   171    7
3800  32.7   27.5   0.8   177    6
4000  36     30     0.8   175    6
4500  49.4   33.3   0.7   142    4

Once I get true fuel flow data I'll be able to confirm if we really do get better economy going faster at 3800RPM than the 3000-3500RPM that seems like it should be better. We typically cruise at 1500-1700RPM, but we're not in any hurry to get anywhere.

[bud37]

Remember those interactive charts are based on hp used at x rpm therefore fuel useage to support that HP.

In real use there will be many other factors at play, for example, tides, currents, wind, sea state, canvas/boat design. So the guide numbers in the link are just that, a guide to get an idea.

Remember the accepted rule for safe fuel reserve on board.....1/3 out, 1/3 back and 1/3 in reserve....try to plan your trips accordingly.

[buster53]

Source of the post I made a chart based on https://www.boat-fuel-economy.com/new/v ... nta-375-hp and the actual speeds I was seeing on my 360. The range and endurance numbers are based on 75% of 280 gallons. None of the numbers account for generator usage. This is the raw data I captured:

Code: Select all

RPM    GPH   Speed  MPG  Range  End.
 600   2.16   3.2   1.5   311   97
1000   4      5.7   1.4   299   53
1500   6.8    7.4   1.1   229   31
2000  13.4    9.2   0.7   144   16
2500  20.6   11.2   0.5   114   10
3000  23     17.4   0.8   159    9
3500  29.4   24     0.8   171    7
3800  32.7   27.5   0.8   177    6
4000  36     30     0.8   175    6
4500  49.4   33.3   0.7   142    4

Once I get true fuel flow data I'll be able to confirm if we really do get better economy going faster at 3800RPM than the 3000-3500RPM that seems like it should be better. We typically cruise at 1500-1700RPM, but we're not in any hurry to get anywhere.

Thanks for this. It confirms the gut feeling I have had for my 356 with 8.1’s.