posted 09-06-2011 01:11 PM ET (US)        

I'll go first. This is based on the last 100 miles logged (via gps) on the boat.

posted 09-06-2011 04:55 PM ET (US)            

Boat continuously get 3.0 nmpg in good weather. Rarely use canvas.

posted 09-06-2011 09:15 PM ET (US)            

I consistently get 3 MPG or better as well.

posted 09-07-2011 08:01 AM ET (US)            

LHG and Martyn, do you happen to have overall average fuel economy figures as apposed to "at cruise"?

Toshbig, can you extrapolate fuel economy from the numbers you posted?

Jimh, is your figure of 3 mpg an overall average including "Unfavorable winds, waves, and non-optimum boat speed"?

posted 09-07-2011 11:15 AM ET (US)            

It appears the 22's with newer engines get around 3 MPG or a little better while the older engines get about 2 to 2.5 MPG.

Looks like the 25's are getting between 1.5 MPG to 2 MPG.

It would also be nice to get MPG comparisons of Whaler Drives to notched transoms.

posted 09-07-2011 11:52 AM ET (US)            

Important to note the this boat can obtain and balance a large amount of weight. The gas tank is 1000L so weight in fuel alone is substantial. Its doesn't seem to affect its balance and performance data at cruise. One thing I have noticed with a full tank is that it does push through the waves more and I have noticed in rough sea I can keep the speed up a bit and not feel what I would normally feel with much less gas. I am thinking I save a bit due to not shifting speeds with a 8000 pounds to lift back up on plane constantly.

I would say 1.8-2 mpg is average and honest. The lower speeds with this particular boat (21-23) are interesting and I think would achieve better? The haul being nearly 10 feet and more like 28-30 feet long tends to keep its bow down even at lower speeds rather than most which stick up at those speeds and gives most unfavorable gas milage. My meters are showing impressive numbers I just have not set the boat at this speed and bothered to measure my data because of a need to get to where I need to be.

At higher speeds more like 35ish the engines rpm are still down at around 4000rpm and overall I would say slightly less mpg then 1.8 my guess without data probably around 1.4. After this point it just gets worse fun but not economical at all.

Martyn

posted 09-07-2011 05:57 PM ET (US)            

The older two-cycle motors are reasonably fuel efficient at their optimum fast cruise. They are not as fuel efficient as a modern motor, but they are not terrible, either. However, what one finds out is that you really don't spend all your time at cruising speed, or at least not as much as you think.

For my REVENGE 22 the long-term average MPG with a classic two-cycle engine was 1.8-MPG. The improvement to 3.0-MPG with a modern motor is very substantial. It is a 1.2-MPG improvement from 1.8-MPG, or an improvement of 67-percent.

posted 09-08-2011 08:50 AM ET (US)            

At cruise (about 32 mph / 4200 rpm's) I can generally get 2.6 - 2.7 mpg

posted 09-08-2011 09:44 AM ET (US)            

This method is in opposition to the method were the distance is estimated by looking at a chart and the fuel use is derived from how much gas you buy at the fuel dock. Both of those measurements tend to be subject to inaccuracy.

The average fuel economy is influenced by the average boat speed, and the faster we go the worse the fuel economy. This is the opposite of many of the boats with older motors, who will tend to always want to go fast, at their optimum cruising speed, because their motors run most efficiently in that relatively narrow speed band. My motor has quite a wide range of planing speed where it is efficient.

In my case I think I have worked out the most fuel efficiency I can in the boat set-up for my type of use. The only options for me to save more fuel would be to change boats to something that was lighter and had a hull surface optimized for efficiency. There may be some savings in a different motor if I went with a naturally aspirated four-cycle engine of moderate horsepower. That might add a few more percent improvement.

posted 09-08-2011 09:49 AM ET (US)            

"On another note, given the small data set we have so far and considering that your boat has a Whaler Drive, it would appear that you obtain the best overall fuel economy among the reporting 22 foot hulls."

posted 09-08-2011 03:39 PM ET (US)            

http://smg.photobucket.com/albums/v395/jimp/Kelsey%20J/ Glacier%20Bay%20Cruise%202005/?start=all

The best the boat has gotten is 3.2 nmpg (that's nautical, not statute). With the 19" MiragePlus propeller we continually cruise at +29 knots at 3,750 RPM and the Merc SmartCraft gauges show anywhere from 9.3-9.7 gph.

posted 09-11-2011 05:51 PM ET (US)            

I have verified this many, many times by calculating the GPS measured boat speed divided by the FloScan measured rate of fuel consumption.

Additionally, I have measued this fuel economy by dividing the miles traveled between Seattle, WA and Neah Bay, WA by the number of gallons of fuel used, on two occasions as well as countless trips between Seattle, WA and Bainbridge Island, WA.

The catch? The motor speed must be kept between 4000 and 4500 RPM to the greatest extent possible to achieve this optimal fuel economy. At 4200 RPM my boat is doing about 35 MPH (30 knots).

posted 09-13-2011 08:53 PM ET (US)            

Tom - I apologize, as I re-read your post and realized that you didn't report "at cruise" specifically as others in this thread have.

I may be investing in a fuel flow meter over the winter to provide a more accurate "real time" measure of my economy and dial in the cruise speeds and maximizing time run at the most efficient speeds, but my cruising usually involves other boaters and very scenic locations that I may not have seen before, so slow speed operation is often necessary, or desired. That and the fact that I don't have a fuel flow meter means I have to rely on an "overall" economy figure derived from careful measure of distance (via gps) and fuel used (by starting with a full tank and finishing with a full tank).

posted 09-14-2011 08:01 AM ET (US)            

Exactly what the boat speed will be when the engine BSFC peaks depends on the boat, the load, and the engine. For boats with plenty of horsepower, for example for Tom Clark's REVENGE 25 with 300-HP in the form of twin engines, the speed at which best fuel economy occurs may be a rather fast planing speed. Tom reports his best fuel economy occurs around 35-MPH.

On boats with more modest power, for example on my REVENGE 22 W-T Whaler Drive with 225-HP, the optimum boat speed for best fuel economy may be slower. Mine was around 28-MPH.

And for boats with really high power, such as L H G's OUTRAGE 25 with 400-HP, I don't have a good feel for fuel economy because I have never seen any actual measurements of fuel economy from L H G. He does not have any way to measure his fuel economy at various speeds. If you do not have a fuel flow sensor you cannot measure fuel consumption in real time. Without measured data we have nothing to compare.

It would be unusual, in my opinion, that the optimum boat speed for fuel economy on a moderate v-hull boat like a Boston Whaler would be as low as 21 to 23-MPH. It is my experience that the 22 to 27-foot Boston Whaler hulls are not easily maintained on plane at those speeds. The hulls are just coming onto plane at 21-MPH. They like to run faster to stay on plane. Because of that, I would be surprised to see that a series of careful and accurate measurements showed that 21 to 23-MPH was the peak of fuel economy for a 22 to 27-foot Boston Whaler hull.

I do not believe for a moment L H G assertions that OMC two-cycle engines are all fuel hogs compared to Mercury two-cycle engines. That is just another example of L H G's brand blindness, and appears to be based not on actual measurements or well-controlled comparison testing but on faith.

posted 09-14-2011 06:17 PM ET (US)         

As an example, I have found the tank mounted, direct reading fuel gauges that Whaler in these used in these Outrages give EXCELLENT repeatable accuracy. Maybe you disagree with that finding.

I have also found that NOAA marine charts are highly accurate on distance measurements and scale accuracy, if you have a good ruler to measure what they are showing you!

With that in mind, I recently ADDED 20 gallons of fuel to my 25 Outrage with twin 200 Mercs, the boat indicated in a prior post, in the Traverse City, MI Municipal Marina.
I noted exactly where the fuel gauge was reading prior to the addition. Mills full canvas set, providing additional wind drag.

We then ran the boat, non-stop, up to Irish Boat Shop's (a Whaler Dealership) Ferry Street Marina in Charlevoix MI, at times running in seas as high as 6' with 20-25 knot cross winds. Some no-wake idling was also involved out of Traverse City and from the Charlevoix Channel entrance through Round Lake. I always idle on only one engine. Cruising speed out on the big Lake was between 25 and 28 MPH (per GPS), and about 2500-2800 RPM's on the tachs. This is not the most efficient running speed for my 25, but that is what we had to do under those conditions.

On arrival back at our slip, with boat still in the water, looking at the floor fuel gauge, I noted that I had not quite used all of the 20 gallons I had added, but it was close. I also figured, from the Chart, that we had run pretty close to 50 statue miles, but not as the crow flies obviously.

So, for this trip, I figured the Merc 200 EFI's fuel economy for these various speed averaged, at 2.5 MPG. Maybe it was somewhere between 2.4 - 2.7 MPG, who cares, but 2.5 is a good enough figure for me to rely on when cruising in reasonably decent weather.

posted 09-15-2011 09:30 AM ET (US)            

quote:

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Boats, no matter how fabulously cared for, cannot tell you their fuel economy at various speeds by themselves.

---

While this is true, its relevance to newt's specific request in this thread is minimal. Newt has requested "average fuel economy" and Larry, with his "fabulously cared for" boats has provided exactly that.

I can think of no more accurate measure of average fuel economy as expressed in MPG than one provided by dividing miles traveled by gallons used. Matter of fact, MPG is the very result of that equation.

posted 09-15-2011 02:27 PM ET (US)         

As a matter of fact, I was going to say that I have found fuel flow sensors to not be that accurate, at least on my Cadillac STS. I can't imagine marine ones are any better. It consistently gives me wrong readings when I measure MPG the old fashioned way, the way our grandfather's did it, which is still THE MOST ACCURATE way.

Fill the tank, drive a distance on your trip until you need gas again, fill the tank back up, divide miles traveled by gallons used. No fuel flow sensor is that accurate.

posted 09-15-2011 03:03 PM ET (US)            

Jim I don't agree with your statemnet unless it was YOUR meter that we are discussing. If ANYONE on the blue planet has his flow meter dialed in to the very drop of fuel it would be you. I bet most people however take them out of the box and reley on the its accuracy without doing much or any calibration....same goes for compasses by the way people.

posted 09-16-2011 08:58 AM ET (US)            

Distance deduced from pacing off lines on a chart is not likely to be as accurate as distance recorded by a GPS receiver on the vessel which tracked the course line.

Fuel used deduced by relying on a fuel tank level float gauge as a precision indicator is not likely to be as accurate as fuel consumption measured with a flow sensor or other fuel flow device.

Modern instrumentation can greatly increase the accuracy of fuel tank level float sensors by using a calibration process. The mechanical dial indicator on a Boston Whaler fuel tank is not calibrated. In fact, L H G himself presented a procedure for calibration of his fuel tank level float gauge which involved carefully filling of the tank and recording of the fuel at various levels. However, in this regard, I doubt that the repeatable accuracy of the fuel tank float and the dial calibration of the gauge can match the accuracy of good flow sensors or other fuel flow measurement techniques.

posted 09-16-2011 11:33 AM ET (US)            

Jim-I am amazed that you would push the envelope to leave only .3gals in your tank. I freak when the light comes on.

LHG-I bought a new to me 24 Baja and ran it for a few weeks before season ended in NJ. The day I pulled the boat it was literally 3-5' in the bay blowing way more than small craft and NOBODY in sight for my 20 min run. In the spring I filled it up and the gauge read 1/4+. It took 97.3gals in a 100 gal tank. I NEVER went by a gauge again, I almost lost the boat that day as NO anchor would have held if I ran out of fuel. Make sure you know your gauge people!

posted 09-16-2011 11:43 AM ET (US)            

For a very rough example:
For a 10 mile trip (11.5 statute) at 10 knots (11.5 mph) with no current, you travel 10 miles (11.5 statute)through the water. 1 hour. The chart & GPS say you covered 10 miles (11.5 statute).

For a 10 mile trip (11.5 mph) against a 1 knot (1.15 mph) current at 10 knots (11.5 mph), you travel 11 miles (12.65 statute) THROUGH THE WATER. 1 hour 9 minutes. The chart & GPS say you covered 10 miles (11.5 statute)

For a 10 mile trip (11.5 statute) with a 1 knot (1.15 mph) current, you travel 9 nautical miles (10.35 statute) THROUGH THE WATER. 54 minutes. The chart & GPS say you covered 10 miles (11.5 statute).

Regardless, one trip doesn't necessarily define you mpg. I swithched props at the start of the season, from a MiragePlus 19" to a MiragePlus 17", and increased my cruising RPMs from 3,750 to 4,200 RPMs and my cruising spreed from 29.3 knots (33.7 mph) to 30 knots (34.5 mph). My SmartCraft gauge tells me I used about 99 gallons of fuel for the season (the Kelsey J is now under a tarp, winterized and we're on to the next project of remodeling the kitchen and dining rom, UGH!). I covered aproximately 290 miles (333.5 statute) and ended with about 2.93 nmpg (3.37 mpg).

As L H G stated on the 14th at 6:17 PM "good enough" is the answer". Overall, this summer, 2.9 nmpg is "good enough". A bit worse with the 17" than the 19", but the 2003 225 Optimax is WAY better than the 1989 225 carbed Johnson (roughly 50% better).

And yes, I use nautical miles and knots because I grew up that way and my charts are in nautical miles. Conversion 1 nautical mile = 1.15 atatute miles.

posted 09-17-2011 09:38 AM ET (US)            

Jim's observation of a 50-percent improvement in fuel economy when changing from a classic two-cycle to a modern engine is in the same ballpark as mine; I observed about a 67-percent improvement.

Even a process which has some error can produce an accurate measurement if the error is random and if the measurements are made over and over. A truly random error will tend to cancel itself if enough measurements are made. A classic example is the measurement of the height of Mount Everest. The height of Mount Everest was measured by a survey party who began from sea level and worked inland. They made thousands and thousands of measurements of elevation. The error in their measurement process was random, and it did not produce a significant error in the final outcome. Some climbers took a precision GPS to Mount Everest. The elevation obtained was within a few feet of the traditional value from the survey 100-years earlier.

The problem I see with boaters and their boat fuel economy is that there is not a random error. The people making the measurements often have a tendency to influence the direction of the error or imprecision in a favorable way. The measurements made by devices like a GPS receiver for distance and a fuel flow sensor for fuel flow are typically impartial, and they are not disposed to be biased.

posted 09-17-2011 10:32 AM ET (US)            

Correct.

I wrote it wrong. What I meant by "covering more ground" was referring to speed. Could have said "covering more ground (or less) "at the greater (or less} speed in the same amount of time." Or something like that. And GPS does get the distance right over the bottom.

Anyway, a 1-knot current at 20 knots can give you roughly a 5% error. At higher speeds, there is less impact.

And with normal cruising/dayboat mode with the 19" MiragePlus I was up to 3.2 nmpg (about 3.68 mpg) and a roughly 63% increase over the old 225. Needless to say, the new engines are a lot better than the old.

posted 09-17-2011 11:59 AM ET (US)            

I think you are right the 4000rpm seems to make a huge difference for these engines as well the way a bigger boat operates with them. There really was not to much in between the low speeds at 23mph and the 28-30 mph range. Its like another gear in a car.

posted 09-17-2011 04:12 PM ET (US)            

quote:

---

I consistently get 2.5 MPG at cruise, running about 30 MPH at 2800 RPM.

---

Then the story changes...

quote:

---

I recently ADDED 20 gallons of fuel to my 25 Outrage...I noted exactly where the fuel gauge was reading prior to the addition.

...

On arrival back at our slip, with boat still in the water, looking at the floor fuel gauge, I noted that I had not quite used all of the 20 gallons I had added, but it was close. I also figured, from the Chart, that we had run pretty close to 50 statue miles...So, for this trip, I figured the Merc 200 EFI's fuel economy for these various speed averaged, at 2.5 MPG.

---

I don't believe that finding a spot on the tank indicator is as accurate as filling the tank to full to measure economy. Granted, neither method is as accurate as using a fuel flow meter, but Larry doesn't like them; however, he does agree with me about filling the tank to full to get an accurate measure of fuel used.

quote:

---

As a matter of fact, I was going to say that I have found fuel flow sensors to not be that accurate, at least on my Cadillac STS. I can't imagine marine ones are any better. It consistently gives me wrong readings when I measure MPG the old fashioned way, the way our grandfather's did it, which is still THE MOST ACCURATE way.

Fill the tank, drive a distance on your trip until you need gas again, fill the tank back up, divide miles traveled by gallons used. No fuel flow sensor is that accurate.

---

I'm glad that L H G agrees with me on the second most accurate way to measure overall fuel economy, however, I believe his original post above defends my position that he reported "at cruise" economy. Given the information I had, that was an accurate assessment.

I find it difficult to believe that normally aspirated 2-stroke Mercury and OMC motors deliver vastly different fuel economy figures. I think we're seeing the difference that comes from propeller selection, motor mounting method, operational differences (speed, conditions, etc) and variations in the quality of data reported (and that includes mine, however, I provided my data collection method in my original post).

posted 09-17-2011 04:28 PM ET (US)            

However, measuring how much fuel has been used leaves open many chances for error. As the owner of a 25 foot Whaler I can tell you that the 140 gallon tank's float gauge is a poor tool to use to figure out when 20 gallons has been used.

I use a calibrated FloScan fuel flow meter in my boat and it's accuracy is superb. I always fill my tank full...at the same gas station...with the boat parked in front of the same pump...pointed in the same direction. I usually put 110-125 gallons aboard and the FloScan totalizer never varies from the amount of gas I pump by more than a gallon, many times it is within a few tenths of a gallon.

posted 09-17-2011 04:37 PM ET (US)            

I too do not believe there is as profound a difference in fuel economy between twenty year old OMC outboard motors and twenty year old Mercury outboard motors as the data presented so far suggets. Propeller selection, motor mounting height, cruise speed and trim all come into play to achieve optimal fuel economy and many here would do well to study the subject in greater depth. Too many older Whalers are simply not well set up.

posted 09-17-2011 05:25 PM ET (US)            

I have had the beast for about two seasons and I am still in a learning curb with it. If one wants to get real technical with data it will take along time to perfect.

posted 09-18-2011 10:49 AM ET (US)            

Back in the dark ages when I ran old technology outboards, I used to cruise at their "happy" speed. Happy speed was when your engine quieted down and the hull ran flat with a nice flat wake...you could hear it and feel it. Today with 4 strokes that is not really possible as they are always happy and quiet. Can't speak for DFI's. I think the EFI is part of it as well as there is no transitions from low speed to high speed jets, etc. Basically I cruise at 41-4200 @ 25-26mph in the Revenge as it seems happy there and from what I have read, should be a good spot to be at.

posted 09-18-2011 02:22 PM ET (US)            

I have a hard time cruising under 30 mph if I have the opportunity to cruise faster. Well, I suppose I'm not cruising when I'm going faster.... :-)

posted 09-19-2011 10:27 PM ET (US)            

My boat has more than three times the horsepower of your Whaler. My boat weighs more than three times the weight of your Whaler. So it seems logical that it would take three times as much energy to move it a given distance.

posted 09-20-2011 12:49 AM ET (US)            

How many hours on your 21 year old motors?

posted 09-25-2011 04:11 PM ET (US)            

Devices like a FLO-SCAN seem particularly well suited for older two-cycle engine fuel measurement because the older engines still have substantial fuel low at lower engine speeds. I found that I could NOT get accurate fuel flow readings with a fuel flow sensor at low engine speeds because my direct fuel-injection engine used very little fuel at those speeds, typically less than 0.2-GPH flow. The turbine sensor was not very accurate at those flow rates, and tended to indicate a fuel flow that was lower than actual.

At higher fuel flow rates, such as reported for twin engines of 225-HP running at 4,000-RPM, the fuel flow rate should be large enough that a device like a FLO-SCAN is in a measuring range where it can be very accurate.

I am surprised that twin 225-HP engines running at 4,000-RPM only consume a total of 12-GPH. If we use a figure for brake specific fuel consumption of 0.5-lbs/HP-hour, this implies that a flow of 12-GPH would be producing

12-gallons x 6.25-lbs/1-gallon x 1-HR-hour/0.5-lbs = 150-HP

posted 09-25-2011 04:25 PM ET (US)            

quote:

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...[The wieght is ]...

---

Jim -- The word is spelled weight not wieght[/b]. Since you love correcting trivial errors and then broadcasting the corrections to the world, I am sure you appreciate my bringing this mistake to your attention and sharing it with everybody.

posted 09-26-2011 01:05 PM ET (US)            

1. You cannot compare motors on an RPM to RPM basis. An Optimax redlines at 5750. A Suzuki 225 redlines at 6100. Go look at the Mercury test reports. At 4000 RPM the fuel burn ranges from 10 to 11 GPH. I bet that a Suzuki 225 probably needs to spin close to 4500 RPM to produce the same speed the Optimax does at 4000 RPM. At 4500 RPM a Suzuki is burning 11 GPH.

2. I guarantee that a 1993 Johnson Ocean Runner 225 does not burn 8 GPH at 4000 RPM. Try more like 13.

posted 09-26-2011 02:20 PM ET (US)            

Now comparing my 225 to the Optis, my 225 got 3mpg at cruise. I can't see how twin 225 Optis would almost double my efficiency with 2.8-2.9 and hence why I said maybe 150's. For a pair of twin 225's to fetch 2.9mpg they would need to burn 11GPH for the PAIR...not going to happen at 4k like martyn said above, he needs to double that 11gph. My 225 was on a Kevlar hulled 20' Hydrasport that weighed 1/3 his weight. So with DFI's he is getting about 1.5-1.6, my carbed would have been about 1.2 in twin setup on his rig.

posted 09-26-2011 02:46 PM ET (US)            

The old 25 Whaler Walkaround (wide-body) were setup mainly with 1989-90 twin Blackmax 175hp. It would be interesting to see what they got in MPG. The other owner had them before switching to these DFI's so maybe I can dig some data from him and share on this thread. Twin 225 modern DFI's are slightly on the larger side of what this boat is normally powered with. I'm not too surprised it can achieve these numbers. Its quite powerful setup which can be run a little faster back off and cruise gaining a little more efficiently at these speeds in the 30mph range. I was just running them way to conservatively most times. Lesson learned!

posted 09-26-2011 05:02 PM ET (US)            

Unfortunately, I cannot recommend the Offshore (VenSura) for your boat; there were the worst of all the propellers I have tested on My Revenge 25 with its twin Mercury 150s. No grip at all.

posted 09-26-2011 06:31 PM ET (US)            

800rpm 4.7mph 1.18mpg
1100rpm 6.1mph 1.02mpg
3300rpm 24.2mph 1.73mpg
3600rpm 29.0mph 1.74mpg
3700rpm 29.2mph 1.68mpg
3800rpm 31.2mph 1.73mpg
4000rpm 32.6mph 7.72mpg
4700rpm 38.9mph 1.16mpg

Running on one engine only:
800rpms 3.5mph 1.2mpg (I want to recheck this one)
1100rpms 4.8mph 2.1mpg
1200rpms 5.0mph 1.9mpg