D12 fuel consumotion

[hkikis]

Hello guys...
I am trying to make some miles in low rpm... 900!! Because I know the fuel consumption is very low. I am travelling with 9.5knots when the sea is very calm. My normal cruise is 1900rpm 25 knots

Anyone knows exactly fuel consumption at 900 and 1900 rpm?

 

[dustywings]

Will of course depend on which version of D12 and in what boat. I have the 715hp versions in my Squadron 58 and reckon at 900rpm I am burning about 29 lph, at 1900rpm about 170lph. The important bit is of course the litres per mile which at 900rpm is 3.12 and at 1900 is 7.14!

 

[hkikis]

I have sq55 715 engines so you told me exactly the numbers that I need!! Haha
Are you sure about 170? I thought that will be a little bit more... Do you have fuel consumption meter? I want to connect with my Sinbad the nemea cables to be able to see everything.

Also about 29 are you sure too? I thought around 40 from a table that I have see on internet. 29 is perfect!!

 

[Portofino]

I have fuel meters with MAN .
12.8 L inline 6 , 700 s .
with a smaller hull .
About 825 - 870 is D speed without pushing a bow wave .
looking at 15/18 L a side so 30 to 36 L/hr....same 9 knot ish ?

1900 would be in excess of 100 , say 105 per side so that’s 200 + guess I dont really go that high.

27;28 knots is easy to do at 1780 rpm around 90 or 180 L / hr is what I see .

its EDC but not Common rail , and as said different hull .

900 I think is a bit high ....but I don't know your g box ratio or prop pitch .

Mine are high pitch because the smaller boat 18 / 19 tons and 4.2 beam with the same 700 Hp or so can accommodate a bigger pitched prop .
Having said that with your wider beam extra 6 tons , bigger free board ( more aero drag in a headwind ) your props might be finer pitched so you need a bit more rpm ...hence the 900 instead of my 825 .

Btw the load for me @ theses 800 rpm levels is 55 % .@ 9 knots .


Its 78/80 % @ 28 knots 1780 ish . @28 knots .

If those squady 58 numbers 170 L/hr @1900 rpm are true it’s either a very efficient hull from a drag pov and the D12 s are fuel efficient, with that g box / prop set up .Not fast . ...just fuel efficient.

170 L / hr I,am looking at 1600 rpm , the turbo boost is low just getting going .Pissing around down at 22/23 knots with my bow high as the hull can’t generate enough lift at the stern to bring it down .