AD41 Consumption

[Max Chat]

Does anyone know what the consumption is of AD41's at cruising speed, approx 20 - 22 Knots? I'm looking to move to a Sealine Statesman 330, and just wanted to verify the numbers I'm being told by the broker.

 

[neale]

That boat is on drives so I would guess you would get around 2 - 2.5mpg at that speed.

 

[DAVIDO]

Our last boat was a 328 sealine with AD41s. The last good run we had down to Padstow from Penarth she used 3ltrs per mile. Hope that helps.

 

[neale]

Our last boat was a 328 sealine with AD41s. The last good run we had down to Padstow from Penarth she used 3ltrs per mile. Hope that helps.

That's 1.5mpg. Seems very low for a 32ft outdrive boat. Would expect that kind of figure from a shaft drive boat with AD41's.

 

[volvopaul]

2 mpg on a good day with clean bottom.

The best i ever got from a 31ft shaft drive corniche was 1.75mpg.

 

[Morpheous]

On a Sunseeker Portofino 31 with AD41 A's and DPE drives I get 2.75 mpg on average and cruise at 20 - 22 knots which works out at about 8gph I think. Goes down to 2 mpg at 30 knots, best seems to be about 18 knots which gives me 3 mpg or 6gph.

 

[PRH]

Shaft drive Corniche averaged over 4 years = 1.5mpg

 

[volvopaul]

Peter, the cornich I bought was from universal in 2005, spent most of its life at foulkes yard.

 

[mont]

2 x ad41b's, 22 knts, 3,200 rpm, medium loaded, light swell, little tabs and legs out to 0 or +1 then usually 2.3 mpg plus.
Modest sea, tabs down, legs in at -4 then usually 2 mpg max.
Or just in case:- off the plane or on the hump then start thinking more towards 1.5mpg.

 

[tamarind]

My fairline targa 33 with 41's burns about 8/10 GPH around 22 knots. Figures obviously depend on how clean the bottom and drives are.

 

[PRH]

Peter, the cornich I bought was from universal in 2005, spent most of its life at foulkes yard.

Bought mine from Eastbourne and kept it at Gosport - it is up for sale at Swanwick at the mo....

 

[neale]

There you go, I guess you have your answer. My original guess was about right but could go as low as 1.5mpg or as high as 2.75.

What were you told????

 

[Pendana]

As a rule of thumb, a direct injection diesel engine burns approx 0.21 litres per horsepower per hour at full chat. Reducing revs to a cruise level ( about -10%) should half the consumption.
So for a pair of AD41's 400hp*0.21 = 84 litres per hour at 3800 rpm.
Reduce to say 3200 rpm for cruise and consumption is about 42 litres per hour or about 9.3 gallons per hour.

Eddie

 

[PowerYachtBlog]

my 41s Ds 1993/94 used to drink about 45/50 LPH combined at 3000 rpm at 3100 used to be about 5 lph more, they start to drink more once you hear the turbo whistle at about 3200/3300
earlier 41s should drink about 5 lph per hour more

 

[poltergeist]

As a rule of thumb, a direct injection diesel engine burns approx 0.21 litres per horsepower per hour at full chat.

Eddie

Sorry for the slight thread hijack/drift, but is there a acknowledged burn rate for the newer common rail D Series engines per horsepower?

 

[Max Chat]

Thanks for the reply, really helped! Decision made, going for the Statesman 330...just need to find one now!

As a rule of thumb, a direct injection diesel engine burns approx 0.21 litres per horsepower per hour at full chat. Reducing revs to a cruise level ( about -10%) should half the consumption.
So for a pair of AD41's 400hp*0.21 = 84 litres per hour at 3800 rpm.
Reduce to say 3200 rpm for cruise and consumption is about 42 litres per hour or about 9.3 gallons per hour.

Eddie

 

[ulyden]

Fuel cons VP41

As a rule of thumb, a direct injection diesel engine burns approx 0.21 litres per horsepower per hour at full chat. Reducing revs to a cruise level ( about -10%) should half the consumption.
So for a pair of AD41's 400hp*0.21 = 84 litres per hour at 3800 rpm.
Reduce to say 3200 rpm for cruise and consumption is about 42 litres per hour or about 9.3 gallons per hour.

Eddie

For a big ship the propeller curve is defines as (speed/rated speed)^3
Power boats and planning hulls are using more (speed/rated speed )^2.5
above frude volume number 4.2.

I think the 41 engines are using more than 270g/kwh or 46l/h at 3800rpm
and correct propeller! If you reduce to max crusing speed 3600 the consumption is (3600/3800)^2.5 * full load consumption or ca 40liter/h
Reducing to 3200rpm the power is (3200/3800)^2.5 = 65% of full load.
With a constant spesific consumption that means 30l/h

Most of the engines are using 230-240g/kwh at full load and 210-220g/kwh at part load (Propeller curve) To get closer use e faktor of 2.7 instead!
I have tested it on a lot of boat and engine tests!

Also remember that engine builder curves are included 5% tolerance!