Voyage consumption formula.

[Oceanride007]

Looking thru some old Marine Engineering notes, I found this interesting formula:

VFC1/VFC2 = (V1/V2)^2 x (Disp1/Disp2)^(2/3) x (Dist1/Dist2)
Where VFC is Voyage fuel consumption, V is velocity, Disp is Displacement, Dist is Distance
Its meant for similar ships or comparing a ship at loaded condition against a ballast voyage. Or just estimating how much fuel you need for a particular motored voyage


So on my 41 ft vessel with no sail assistance; if I used 5lt of fuel at 6 knots, and I have 250 litres on board how far can I go, at 7 knots 6 knots and 5 knots. And Leaving 20 % in reserve. Ignore change in disp.


Answer 176 miles at 7 knots, 240 at 6 knots, 345 miles at 5 knots.
Note: only works for =< than boat speed and would imagine fuel consumption is optimistic where the specific fuel consumption curve drops off.


Formula for Daily Fuel Consumption is:
DFC1/DFC2 = (V1/V2)^3 so at 4.7 knots my daily Fuel consumption would be decrease by a half, give or take.

[Meanderthal]

I wrote this down. Thanks! What textbook did that class use?

[Oceanride007]

Was actually class notes in Naval Architecture, only reference book mentioned in my notes is Reeds, Naval Architecture. Lots of interesting stuff on friction, model testing. Its all pretty closely related to Admiralty Co-efficient look it up in your favorite search engine.