Fuel usage

[bartdog]

Went out recently on Lake Coniston on my 3.4m Quicksilver SIB using a Yam 3hp Malta I came by, instead of the Tohatsu 9.8. Ran out of fuel after about 3-4 miles which surprised me as I thought it would have lasted longer.

Could someone please tell me the rough fuel calculator I have seen on here sometimes. I have tried searching but to no avail.

[Max...]

There is a rule of thumb about 10% of HP in gallons per hour at WOT but I have never found it that accurate.

In all types of use from river pootling to 3/4 throttle cruising to wave jumping antics and everything inbetween I have found my 15 Merc averages between 1.8 and 2.6 NM per litre and I generally work on 2 NM a litre.

On a week's mixed river/sea boating in Devon earlier this month we did 122 NM with 64 litres over 21 hrs moving.

= 1.9 NM per litre or 3 litres an hour.

[bartdog]

Cheers for the reply Max. Does WOT stand for wide open throttle ??

[Max...]

Yes, correct.

[Landlockedpirate]

Im guessing you would have been pretty much WOTall the time ? Its a lot more economical if you drop it back to 3/4 throttle.

But the main reason you ran out of fuel is the tiny integral tank, its less than 3 litres.

[bartdog]

Yes you are right, pretty much WOT all the time

[bartdog]

The motor was purchased mainly for freshwater trolling where it wont be run too hard and only me in the boat instead of two of us. Will give it another try at reduced speed and load just out of interest.
Will remember to take plenty of spare fuel also....rowing a SIB isn't fun