FUEL CONSUMPTION

[penpal]

Dear all, I have installed new 130 hp Ford Onan engines in my old Freeman 32. She is moored in Hythe. I have 55 gallon tanks for each of the two engines and I am trying to work out fuel consumption. My best calculations are coming out at 1.75 litres for each mile. Does this sound right? Has anyone got diesal engines of similar size? My boat is semi displacement, but I tend to not hammer her but travel at 10kn. Hope you can help

 

[Deleted User YDKXO]

Specific fuel consumption for diesel engines about 225g/Kwhr. So, say you're using 100hp = 75Kw @ 10knots, thats equivalent to 16875g/hr. SG of diesel = about 0.9 so thats 18.75litres/hr which @ 10knots = 1.875litres/nm
Yup your figure of 1.75litres/nm sounds about right then but actual fuel consumption will depend also on prop efficiency and other factors

 

[npf1]

Ive got a 115HP Perkins. Uses about 4 Litres per hour at cruising speed.

 

[Frontier]

Have Ford really named an engine Onan /forums/images/graemlins/ooo.gif

 

[fisherman]

Do you mean Otosan?
We reckon a broad rule of thumb is 1 gallon per 20 hp per hour.

 

[jhr]

Onan

Are they Ford? Onan are better known for their generators, presumably so-called because you don't need to hook up to get things going. /forums/images/graemlins/grin.gif

 

[nedmin]

Ive got a 135hp Perkins uses about 5litres/hr mix of tidal and canal at cruising speed