fuel consumption question

zip · 10 February 2013, 23:39

i am considering purchasing a 28 foot zodiac 850 pro with twin Yamaha 4 stroke 150s.
the boat probably weighs around 3000 pounds.

anyone have an idea on what fuel consumption would be at cruise, which i imagine would be somewhere around 25 knots?

Chris · 10 February 2013, 23:57

Quote:

Originally Posted by zip

i am considering purchasing a 28 foot zodiac 850 pro with twin Yamaha 4 stroke 150s.
the boat probably weighs around 3000 pounds.

anyone have an idea on what fuel consumption would be at cruise, which i imagine would be somewhere around 25 knots?

2 litres per mile would be guess.

Doug Stormforce · 11 February 2013, 00:52

About 33l/hr at WOP (Wide Open Throttle) on each engine (so 66l/hr)

Improving to about 24/hr on each engine at cruise speed

I suspect cruise speed may be marginally lower than you expect

zip · 11 February 2013, 01:47

chris, and doug,

great info, thanks.

a little surprised that my cruise is not going to be at least 25. I cruise at 20 on my 14 footer, and it only has a 50hp.

ncp · 11 February 2013, 06:44

My only reference is a friends H733 with twin Yamaha 150 HPDIs. Shorter hull, heavier construction. He'll get anywhere from 1.7 to 2.4 mpg.

GordyP · 11 February 2013, 09:10

Different engines, however with the twin 150 etecs I get a cruise of just over 30 knots and use about 10 gallons an hour or approx 1.8 l / mile.

willk · 11 February 2013, 09:39

Zip, I did some training on a 28 footer with twin Suzuki 150s. She had a cruise speed of aroundabouts what you expect for yours and topped out around 38/39knots if lightly loaded (but was quite a heavy craft, having superstructure). If I recall correctly, she was returning a bit under 2L/Nm at cruise. Video of her below:

Red Bay Powerboating - YouTube

smitty477 · 11 February 2013, 12:37

Yamaha performance bulletins can be a good general source of information as long as you keep in mind your situation will vary some. Below is the Zodiac 850 with twin 150 Yamaha 4 strokes.

Hope this helps

http://www.yamahaoutboards.com/sites...-t-f150txr.pdf

Chris · 11 February 2013, 23:02

Quote:

Originally Posted by smitty477

Yamaha performance bulletins can be a good general source of information as long as you keep in mind your situation will vary some. Below is the Zodiac 850 with twin 150 Yamaha 4 strokes.

Hope this helps

http://www.yamahaoutboards.com/sites...-t-f150txr.pdf

That looks pretty close to what you could expect, close to 120 litres per hour flat out that's pretty scary but at cruising speeds of 30mph 45 litres per hour, so about 1.5 litres per mile which is pretty respetable for 300 HP puhing an 8 meter boat.

smitty477 · 11 February 2013, 23:49

We have twin Yamaha 150's on a 24' Rib and can do a bit better than that burn at most crusing speeds with 4 blade props.I would guess a lot has to do with the exact boat and loading but cruisng speeds can be much more than 25 knots.
Hope this helps

zip · 13 February 2013, 13:17

Great information, thanks.

I'm no request rock scientist, but it appears the faster you go, the more fuel you use. I will definitely hit WOT, but won't keep it there for long.

smitty477 · 13 February 2013, 13:23

"I'm no request rock scientist, but it appears the faster you go, the more fuel you use."

Use the graphs and look carefully at where the gap between the speed and fuel use is the largest.
FWIW - I find that anywhere between 3,000 rpms and near 4,800 rpms gives a very good fuel use per mile travelled.
That leaves a large choice of cruising speeds up to the captain.
Hope this helps