Fuel Consumption D6 350's

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Can anyone tell me what sort of fuel consumption I can expect from VP D6 350's fitted to a Sealine S42? also any S42 owners out there who can recommend best cruising speeds for best fuel consumption.
Thanks for any feedback.

 

[Divemaster1]

...........also any S42 owners out there who can recommend best cruising speeds for best fuel consumption.[\QUOTE]

Not a S42 owner, but the absolutely most economical speed will be hull displacement speed at about 8 knots ... but that may not be what you are looking for...

I think the D6's calculate with about 190 gram per hp hr, so you ought to look at the load curve for the engine / boat to calculate the most efficient planning speed... but at WOT, I'd suspect these to go through roughly 77 L / Hr each.... Drop down to about 3000 RPM, and you should drop to about 50L each with a further 10L reduction if you drop to about 2800.... then it is a question what speed you get out of the boat at the variour RPM's

 

[Nautical]

Can't tell you for an S42 but on an Absolute 45 at 26 knts you will get 1.6 mpg or 34 LPH per engine. Bear in mind the ABS 45 is one of the most efficient hulls around so you might not quite achieve that but won't be far off I guess being that the S42 is a lighter boat.

On an ABS 41 you get 1.75 mpg at 26 knts which would be much the same size as an S42.

 

[PowerYachtBlog]

I found fuel graph on the Volvo site for the D6-370 what should be very similar
at 3000 rpm the D6-370 drinks 45 lph each engine
so might be a bit less for the 350 with the same rpm
at 2800 it is 38 lph
and at 2600 rpm is 33 rpm, 2400 rpm is 27 lph
the max rpm for the D6 370 is 3450 rpm
I imagine 2400 or max 2600 to be a planning speed for the S42
still dont be carried out in LPH figures as then you have to find the most efficient speed for the boat first, and the comfortable speed for you second