D12-800 775hp Fuel consumption

CLOUD9

CLOUD9

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Apologies, I know there are lots of fuel consumption questions, (Ive not managed to look at them all) and Ive also not managed to ask Princess if they have any test or sea trial data yet.
In anticipation of finally getting my hands on the boat... Im planning some trips for the summer. Real-world consumption experience would be really useful in anything similar to a Princess 58 Flybridge 26 tonnes 2 x D12 800 775HP

Im currently working on the Volvo Data Sheet.
Assuming 22 knots at 1900rpm (a bit of a guess as I didn't pay enough attention on the delivery trip with the skipper..)
1900rpm = 85 l/hr each x 2 = 170 l/hr
22/170 = 0.13 nm/l or
22/37.5 = 0.59 nm/gallon

Tanks hold 2818 litres/620 gal:
20% reserve = 564 litres/120 gal

So Range = 2254l x 0.13nm/l = 293 nm

(or 500gal x 0.59nm/gal = 295nm)

Does the panel think that this looks about right??

Thanks for any help.
Rick
 
CLOUD9 said:
Apologies, I know there are lots of fuel consumption questions, (Ive not managed to look at them all) and Ive also not managed to ask Princess if they have any test or sea trial data yet.
In anticipation of finally getting my hands on the boat... Im planning some trips for the summer. Real-world consumption experience would be really useful in anything similar to a Princess 58 Flybridge 26 tonnes 2 x D12 800 775HP

Im currently working on the Volvo Data Sheet.
Assuming 22 knots at 1900rpm (a bit of a guess as I didn't pay enough attention on the delivery trip with the skipper..)
1900rpm = 85 l/hr each x 2 = 170 l/hr
22/170 = 0.13 nm/l or
22/37.5 = 0.59 nm/gallon

Tanks hold 2818 litres/620 gal:
20% reserve = 564 litres/120 gal

So Range = 2254l x 0.13nm/l = 293 nm

(or 500gal x 0.59nm/gal = 295nm)

Does the panel think that this looks about right??

Thanks for any help.
Rick
Click to expand...
Rick I had those engines in a Sq58 (2009 model) from new, with 2800 litre tank and also 26 tonnes. I'd say your figures are good, though I'd have to check bag in my old log book to be sure (I have it somewhere...). I had electronic fuel monitoring on the dash.
I used to do Mahon-Antibes (268nm by GPS) with no worries and a bit less than 1/4 tank showing on the gauge on arrival
If I find the old log book I'll update, but your figures look good to me. Basically I used to work on 300nm range, after which you might have some more miles in the tank but it gets a bit worrying.
All this at 20 knots planning speed cruising
 
CLOUD9 said:
In anticipation of finally getting my hands on the boat... Im planning some trips for the summer. Real-world consumption experience would be really useful in anything similar to a Princess 58 Flybridge 26 tonnes 2 x D12 800 775HP

Im currently working on the Volvo Data Sheet.
Assuming 22 knots at 1900rpm (a bit of a guess as I didn't pay enough attention on the delivery trip with the skipper..)
1900rpm = 85 l/hr each x 2 = 170 l/hr
22/170 = 0.13 nm/l or
22/37.5 = 0.59 nm/gallon

Tanks hold 2818 litres/620 gal:
20% reserve = 564 litres/120 gal

So Range = 2254l x 0.13nm/l = 293 nm

(or 500gal x 0.59nm/gal = 295nm)

Does the panel think that this looks about right??

Thanks for any help.
Rick
Click to expand...


Slight drift, sorry - but is your new boat on a hammerhead at Swanwick, by any chance?
 
jfm said:
Rick I had those engines in a Sq58 (2009 model) from new, with 2800 litre tank and also 26 tonnes. I'd say your figures are good, though I'd have to check bag in my old log book to be sure (I have it somewhere...). I had electronic fuel monitoring on the dash.
I used to do Mahon-Antibes (268nm by GPS) with no worries and a bit less than 1/4 tank showing on the gauge on arrival
If I find the old log book I'll update, but your figures look good to me. Basically I used to work on 300nm range, after which you might have some more miles in the tank but it gets a bit worrying.
All this at 20 knots planning speed cruising
Click to expand...

Thanks JFM thats really helpful. I dont even know if CLOUD9 has the electronic fuel monitoring. It may well have if it was standard Volvo gear in 2007, or maybe not if something special?
 
CLOUD9 said:
Might be.... Ooos asking??

Yes Jimmy, the name will hopefully be applied tomorrow and all will be revealed. Are you visiting Swanwick, or is your location actually Brighton/Antibes/Swanwick? Im there tomorrow.
Click to expand...

I went past this morning, delivering Vega from Brighton to RK Marine. I'll be back in the yard at RK Marine first thing tomorrow morning from about 8am.
 
jimmy_the_builder said:
I went past this morning, delivering Vega from Brighton to RK Marine. I'll be back in the yard at RK Marine first thing tomorrow morning from about 8am.
Click to expand...

Ive just worked out (I think) that you get Vega onto the transport tomorrow. I will look out for you, but it may be all over by the time I get down to Swanwick. Hope all goes well.
 
CLOUD9 said:
Thanks JFM thats really helpful. I dont even know if CLOUD9 has the electronic fuel monitoring. It may well have if it was standard Volvo gear in 2007, or maybe not if something special?
Click to expand...
Unlocking the fuel data is a £1000 Volvo upgrade (see recent threads) and you can then have litres-per-mile readout on your MFDs. The data is fantastic to have, though Volvo's charge for it is eye watering. As a first check, press repeatedly the buttons on the tachos and see if the LCD shows a value for litres per hour. If it does, then you probably have the upgrade already installed
 
CLOUD9 said:
Apologies, I know there are lots of fuel consumption questions, (Ive not managed to look at them all) and Ive also not managed to ask Princess if they have any test or sea trial data yet.
In anticipation of finally getting my hands on the boat... Im planning some trips for the summer. Real-world consumption experience would be really useful in anything similar to a Princess 58 Flybridge 26 tonnes 2 x D12 800 775HP

Im currently working on the Volvo Data Sheet.
Assuming 22 knots at 1900rpm (a bit of a guess as I didn't pay enough attention on the delivery trip with the skipper..)
1900rpm = 85 l/hr each x 2 = 170 l/hr
22/170 = 0.13 nm/l or
22/37.5 = 0.59 nm/gallon

Tanks hold 2818 litres/620 gal:
20% reserve = 564 litres/120 gal

So Range = 2254l x 0.13nm/l = 293 nm

(or 500gal x 0.59nm/gal = 295nm)

Does the panel think that this looks about right??

Thanks for any help.
Rick
Click to expand...

I have the identical hull and almost identical engines, but to be honest I've never worked out my fuel consumption that closely. The MB&Y test on the Princess 60, which is virtually the same size and weight, but with D13-900 engines suggests that fuel consumption doesn't vary much between 1800 and 2200 RPM at about 0.53 MPG, and that will be with spotless hull and sterngear, so it may be better to work on an average of 0.5 MPG to allow for a bit of fouling. Obviously it will deteriorate rapidly if you get more significant prop fouling.
 
Thanks Nick. Always better to be slightly over cautious with these things.
All being well Im taking the boat back to Torquay this week and will top the tanks back up to get an accurate calculation. Its just under 100nm so should get a reasonable idea. Im very much hoping that the Volvo fuel display has been unlocked as JFM has described. Looking at the D12 graph again, on the face of it they are burning 70% more fuel at 2200rpm than at 1800rpm. If the P60 manages much the same consumption (in nm/gal) across that rev range then I guess there is a disproportionate increase in speed/hull efficiency.
 
It seems to vary between hulls, but some planing boats do see very little difference in fuel consumption (in mpg) between fast and slow cruising speeds. Jrudge reported this to be the case with his Squadron 65. I guess it's because the hull lifts further out the water at higher speeds, so wetted surface area reduces as speed increases, thus overall friction doesn't change that much?
 
I skipper a SQ 58 most weeks we get slightly better than that 1700 revs gives us 21 knots and 135 litres an hour we also have the Volvo upgrade. The trip fuel is really useful and it's amazing how much you can save with a small throttle reduction. Enjoy the boat!
 
Handy feature, I created a table of rpm vs speed vs fuel burn and found my boat achieves same 1.72mpg from 2800-3000rpm with speed of 17-20 knots in that range. So I know I get an extra 3 knots for free :D

Also handy to keep track of hull fouling, I was surprised to see +10lph on my single D6-370 last trip out at 3000rpm. I went around boat cleaning growth from waterline last weekend, I'll see if that makes any difference - or it will be time for another lift and scrub.

Anders
 
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