8V71ti's fuel consumption

[Genesis]

Yep. Slow down 2kts and your burn will be cut in half per mile.

Try it - you'll see....

I'm willing to pay in the form of 0.5nmpg of burn to go 18kts (and I do), but not to do 11 or 12. If that's the price of 11 or 12kts I'll slow down to 8 or 9 and burn half that much per mile.

 

[Geoff58yf]

Thanks guys
On our run Aug 7th (about 6hrs) Ill try backing off a little and see how we do. Ill record the speeds and burn and report back.
Geoff.

 

[first230sl]

Murry,
Our Kemosabe is a '78 58yf with 871/ti's. I agree with you that getting my burdened beast up on plane is wishful thinking.

Geoff - thanks for this. Listening to some people with 53s and looking at some of the remarkable claims in Yachtworld had me geginning to worry whether I had one of my props on backwards

Your experience is very much like mine, except I am probably slightly faster than you are - I may be a bit lighter and my props are over, rather than under. Here is what I recorded during one test run:

RPM : Knots

900 : 7.2
1000 : 7.7
1100 : 8.1
1200 : 8.7
1300 : 9.5
1400 : 10.1
1500 : 10.6
1600 : 11.1
1700 : 11.7
1800 : 12.4
1900 : 13.1
2000 : 13.9
MAX : 15.4 (port at 2190 RMP, stbd at 2130 rpm)

And as I say - I never get on plane. My fiel burn at 1500 is roughly 15 US gallons per hour, but I'll know better today as I am going to fill up after a 25 hour run.

Take care - and thanks for setting my mind at ease.

Murray

 

[Pascal]

reading this discussion, i feel better about my decision to get Naturals...

Murray, you'd definitely save a lot of fuel slowing down a knot or so if you can keep the engines warms... you're also almost 200rpm short at WOT, that's pretty significant. I am too...

 

[MikeP]

Here are the speed figures for our '80 53MY/8V71Tis taken at the beginning of the season with 1/2 fuel (around 350 gal) and 1/3 water (around 100gal). It is GPS two-way speed, NOT speed through the water.

Rpm/knots

Idle/5
750/6
1000/7
1250/9
1500/10
1750/11
2000/14
2150/16
2300/18

She won't hit the 18 or even the 16 now... (650 gal fuel/ 280 gal water)