capnsensible
Well-known member
I have been looking for a fuel consumption/revs curve for these engines for some time with a notable lack of success. Can anyone point me in the right direction?? Fitted to a Sunseeker. Many thanks.
MAN 850 Fuel Graph
- Thread starter capnsensible
- Start date
PowerYachtBlog
Well-known member
i think that will be impossible unless you get a boat report with these graphs
still the consumption per revs rate of the normal engine graphs holds always true
what you will need to do is calculate the speed yourself
also seeing the engine and I imagine the boat to be a bit old (over 10 years old) I suggest you go on and calculate with the engine graphs, as it is normal for the engines to loose some peaks in performance
still if this engine is MAN 820 it is one of the most beautiful engines out there
still the consumption per revs rate of the normal engine graphs holds always true
what you will need to do is calculate the speed yourself
also seeing the engine and I imagine the boat to be a bit old (over 10 years old) I suggest you go on and calculate with the engine graphs, as it is normal for the engines to loose some peaks in performance
still if this engine is MAN 820 it is one of the most beautiful engines out there
volvopaul
Well-known member
These engines use a horrendous amount of fuel being a v8 and 12000cc, though totally unstressed at 680hp no doubt they will be getting nearer 1000hp from the same block I would think by now with edc and common rail fuel systems etc.
I would think you will use 40 gallons per hour at a modest cruise speed say 20 knots 1/2 mile per gallon rule of thumb.
Nearly bought an old carribean 52 once with one knackered 680man in it other one was ok but swmbo at that time put the stops on it, she is nolonger my present swmbo.
I now have another one who obeys me, well most of the time anyway.!.
I would think you will use 40 gallons per hour at a modest cruise speed say 20 knots 1/2 mile per gallon rule of thumb.
Nearly bought an old carribean 52 once with one knackered 680man in it other one was ok but swmbo at that time put the stops on it, she is nolonger my present swmbo.
I now have another one who obeys me, well most of the time anyway.!.
capnsensible
Well-known member
Cheers, yes, we fetched the boat to the Canaries last September from Majorca and indeed at a cruising speed of about 19 knots I figured on 200l odd per hour. I am interested in the consumption at lower speed ranges when we are jilling along at 6 knots or so doing a bit of fishing (dont laugh) and at the top end when we are wizzing back for kick off (although this can wait till August!) I once ran a 47 foot boat that had a most excellent graph for a pair of Caterpillar engines and found it very useful but have been unable to find anything for MAN.
djefabs
Member
Have a look at this, it might help. I have MAN D2848LE4 680 hp engines in my Squadron and am very pleased with them. Approx 9 ltrs/ nm at 1900/2000rpm gives 22/24 knots.
http://www.man-mec.com/2848_specs.htm
Derek
http://www.man-mec.com/2848_specs.htm
Derek
Hurricane
Well-known member
I know it is a totally different engine (straight 6 although they are 12000cc) but we have a pair of Volvo D12s (EDC) rated at the same sort of output (675hp each)
Crusing at a similar speed to Derek (djefabs) of 22 to 24 knots we use about 7.2 litres per nautical mile on a 51 foot 20 ton Sealine flybridge.
Sometimes we do as you are saying - cruise at a much slower (displacement) speed. Good if you cant make the a "tidal gate" and want to "chill out" and take your time until the next high water etc. We dont go quite as slow as you are saying - about 8/9 knots - this relates to about 850 RPM (engines peak at about 2300 RPM and cruise at about 2000 RPM). At this slower speed we only burn between 2 and 3 litres per nautical mile giving us a range of over 600 miles.
Crusing at a similar speed to Derek (djefabs) of 22 to 24 knots we use about 7.2 litres per nautical mile on a 51 foot 20 ton Sealine flybridge.
Sometimes we do as you are saying - cruise at a much slower (displacement) speed. Good if you cant make the a "tidal gate" and want to "chill out" and take your time until the next high water etc. We dont go quite as slow as you are saying - about 8/9 knots - this relates to about 850 RPM (engines peak at about 2300 RPM and cruise at about 2000 RPM). At this slower speed we only burn between 2 and 3 litres per nautical mile giving us a range of over 600 miles.