Fueleconomy 175-250 hp.

joakimhansson · 01 July 2006, 09:29

If you have a 250 on a rib and a 175-200 on another. If you will drive the same distance with both boats and the same speed. Most of the time will be cruising speed.

And if you don´t drive faster with the 250 than the 175-200. What will the difference in fueleconomy be?

(Do you understund?)

codprawn · 01 July 2006, 12:07

I think I know what you mean.

It all depends on throttle settings - if the 175 needs say 5000rpm to keep up with the 250 running at 4000rpm then prob the 250 will use less fuel.

Having said that so much depends on engines - props etc etc.

It seems to me most people with big RIBs get roughly the same sort of fuel economy no matter what big engine they are using.

Roy Smith · 01 July 2006, 22:16

We have a Yamaha 250 Four/stroke dose appox 1.25 lts to the mile at approx 5000 RPM

Roy Smith · 01 July 2006, 22:18

Just a thought next week weather permtting there is a cruise to Alderney
would be good to see what people are getting in the real world

MarkM · 02 July 2006, 10:25

I did a bit of a study on this for months.

On the back of the Scorpion 7,5 I had an Evinrude 150 Ficht. At 3750 rpm it did 50km/hr with 32 liter/hour. At 5000 rpm, 60km/hr, 53l/hr.

Later I changed to an Evinrude 250 DI:
At 3500rpm also 50km/hr with 32 l/hr.
At 4000rpm, 60km/hr, 40l/hr.

As you can see the 150 was too light for this boat. With the 250 at 60km/hr it's 13 liters per hour cheaper. At WOT it is not

85 l/hr, but with 98km/hr

.
I'm very happy with the change. Especially in the rough it takes less fuel to get over the waves or against the tide.

joakimhansson · 02 July 2006, 13:15

Yes

More expensive to buy but cheaper to drive. The noiselevel must be much better to....

Yes...now i can tell my girlfriend that we "need" a 250 on the rib.

MarkM · 02 July 2006, 14:22

With the 150 most of the time I was traveling in the 5000rpm range. Now with the 250 it's more the 3500 to 4000rpm range.
The orange line shows the range with an amount of fuel. The higher the figure, the further the distance you can travel with that amount of fuel. Ofcourse at 1000rpm you get very far but it takes ages; at around 4000rpm you travel very economically with a reasonably speed.

Hugh Jardon · 04 July 2006, 09:30

my opti 200 on the vipermax 6.5 seems to be working out superb with an overall average from the smartcraft of 4.4 miles per usa gal. on sat in pwilly we used 61 quid of fuel, this was the same as some smaller boats with 80 hp fourstokes and less than some boats with 115 fourstrokes. Brad used similar fuel with his 100 hp

really chuffed and my initial concerns about how much fuel we would use have gone away. And, it is probably fair to say that we dont exactly drive economically!! the new prop has increased my fuel mpg!!

very happy all round and would defo recommend an opti

floater · 04 July 2006, 17:33

god my engine must be using some fuel then as i used 35l on saturday and iknow that you went further as you went over to the islands at abersoch
30hp at 25mph 4800-5000rpm 35l on trip not sure of distance

Hugh Jardon · 04 July 2006, 17:41

Quote:

Originally Posted by floater

god my engine must be using some fuel then as i used 35l on saturday and iknow that you went further as you went over to the islands at abersoch
30hp at 25mph 4800-5000rpm 35l on trip not sure of distance

i filled mine to the brim on friday and then filled it to the brim again on sunday morning before we went out for a bit of a spin so that is an accurate fuel usage

our speed varied up to around 50 plus on both days with quite some time spent at the higher throttle settings

Alex-341 · 04 July 2006, 21:26

Yes i remember talking to you about that, were at WOT all he time pretty much. During the weekend we had her fully trimmed out at full power all the way, just touching 31 knots. This probably explains the poor fuel comsumption.

Whats sort of RPM were you at most of the time and WOT speed?

Mrs Jardon · 04 July 2006, 22:33

Quote:

Originally Posted by zodiac rover

Yes i remember talking to you about that, were at WOT all he time pretty much. During the weekend we had her fully trimmed out at full power all the way, just touching 31 knots. This probably explains the poor fuel comsumption.

Whats sort of RPM were you at most of the time and WOT speed?

for us wot is around 47knots / 53-54 mph at around 5400 rpm but i can not swear to the rpm as never looked close enough when zipping along. the speed most folks seems to be doing was around 40 -45 mph at the front and we spent a good bit of time going reasonably fast with spurts of wot. I guess we were cruising anywhere around 35-50 mph as we would change position in the pack. we would look for wakes to jump and play around which would cause us to change position quite a lot.

i think our economy is down to the engine reasonably effortlessly pushing the boat along. when on the plane and it has a planing pad it is very easy going. Some of the smaller engines were at wot most of the day i suspect and this is never a good economical approach.

so for me the day was even more enjoyable knowing we had only burnt a reasonably frugal amount of fuel as fuel consumption was a big concern of mine prior to the purchase of the engine. i was really pleased to return fuel consumption better than or equal to smaller 4 strokes.

i can honestly say i love my opti lots

using the mrs pc here

chris

Rogue Wave · 05 July 2006, 10:55

you do get a lo of bang for your buck with an Opti