Fuel consumption at low enginge speeds

[markosy]

I have a Fletcher Faro fitted with a 70 HP Tohatsu 2 stroke EPTO outboard which I currently use on the locked section of the Thames. Running the engine at 1500-2000 rpm due to speed restrictions it uses approx 1 L per mile. I am planning a trip on the tidal section and enquire if the engine will use less fuel per mile at higher speeds and when the boat is on the plane

 

[DoubleVision]

Hi Mark. Your engine will use around 3 to5 gallons an hour at planing speeds I recon from experience--i`ll leave the maths to you.

 

[SkipperMarv]

I know it is a differnt league all together but a recent experience with a Fleming 55 will be a good example of fuel consumption at different speeds.

We left the Hamble for Falmouth and ran at 2000rpm/13kts for the trip and used 9litres per mile

We then ran Falmouth to Villamoura Marina in Portugal at 1300rpm/8kts and used 2.5litres per mile.

Quite a difference, so to answer your question you will use lots more fuel at planing speeds, but it is great fun on the plane.

Blow the fuel consumption, enjoy yourself, that is what boats are for

/forums/images/graemlins/grin.gif

 

[landlockedpirate]

Years ago we had a Fletcher 155 ski boat with a 90hp Yamaha on it. With mixed use throughout a full day at planing speeds we used to get about 4mpg. Your engine is smaller, but the boat heavier so i think it would be similar.

One reason it may be a lot worse is the speed limit on the higher tidal Thames, 8kts is a really bad speed for fuel consumption in a boat like yours.

Mark