Cost of Fuel at Full Speed (WOT), at 3500 RPM (Cruising Speed) and at 2500 RPM (a Comfortable Slow S

Eagle 1

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How many dollars per mile do you spend at full speed (WOT), at 3500 RPM (Cruising Speed) and at 2500 RPM (Slow Speed)?

Have you ever wondered what the fuel costs are to run your boat engine?

http://www.yamahaoutboards.com/owner-resources/performance-bulletins

Based upon the Yamaha Performance Bulletin measurements from the above website, and using an estimate of $5.00 per gallon as an average cost of gasoline, I have estimated what the fuel costs should be for full speed (at WOT), cruising  speed (at 3500 RPM), and a comfortable slow speed (at 2500 RPM) for Yamaha 250 HP engines, Yamaha 200 HP engines, and Yamaha 150 HP engine respectively.  (The 250 HP and the 200 HP Yamaha engines were each mounted on separate 2375 GCWs, while the 150 HP engine was mounted on a 2275 RLi.)

If my calculations are correct:

The Yamaha 250 HP (on a 2375 GCW) will cost you about $107.50 per hour at a full speed of 44.6 MPH (at 6000 RPM using 21.5 GPH); and will cost you about $29 per hour at a 3500 MPH (a cruising speed of 20.8 MPH using 5.8 GPH); and will cost you only $19.50 per hour at a 2500 RPM (a slow comfortable speed of 12 MPH using only 3.9 GPH).

The Yamaha 200 HP (on a 2375 GCW) will cost you about $92 per hour at a full speed of 40.0 MPH (at 5800 RPM using 18.4 GPH); and will cost you about $26 per hour at a cruising speed of 21.5 MPH (at 3500 RPM using 5.2 GPH); and will cost you only $15.50 per hour at 2500 RPM (a comfortable a slow speed of 11.7 MPH using only 3.1 GPH).

The Yamaha 150 HP (on a 2275 RLi) will cost you $78 per hour at a full speed of 37.6 MPH (at 5700 RPM using 15.6 GPH); and will cost you  $25.50 per hour at a cruising speed of 20.8 MPH (at 3500 RPM using 5.1 GPH); and will cost you only $13.50 per hour at 2500 RPM (a slow speed of 11.3 MPH using only 2.7 GPH).

Since my wife and I are 62 and 59 respectively we will be content to run our boat slowly at about 10 MPH just to enjoy the beauty of nature and to see the sights.  I estimate this will cost me about $12.50 per hour at 10 MPH at about 2300 RPM using about 2.5 GPH at $5 per gallon.

For me, next year I will have a  2014  year Bennington  2375 GCW model with a  150  HP engine.   

At WOT I expect to go about  37  MPH at  5800  RPM.   According to the Yamaha Performance Bulletin (Y.P.B.) I will probably use up about  15.7  GPH at WOT.  Multiplying this same  15.7  GPH times $5 per gallon means it will cost me about  $78  dollars per hour to run my boat at full speed for a whole hour; and this same  $78  per hour DIVIDED BY 37 MPH means it will cost me about  $2.10  dollars per mile for every mile I run my boat at full speed.  (I’ve never run my boat at full speed for an entire hour.  Who does that?)

At 3500 RPM I will probably run about  19  MPH and according to the YPB I will probably use up about  5.2  GPH at 3500 RPM.  Multiplying this same  5.2  GPH times $5 per gallon means it will cost me about  $26  dollars per hour to run my boat at cruising speed for a whole hour;  and this same  $26  dollars per hour DIVIDED BY 19 MPH means it will cost me about  $1.37  dollars per mile to run my boat continuously at cruising speed.

At 2500 RPM I will probably run about  11  MPH and according to the YPB I will probably use up about  2.7  GPH at 2500 RPM.   Multiplying this same  2.7  GPH  times $5 per gallon means it will cost me about  $13.50  dollars per hour to run my boat at a slow comfortable speed for a whole hour; and this same  $13.50  dollars per hour DIVIDED BY  11  MPH  means it will cost me about $1.25  dollars per mile to run my boat continuously at a slow comfortable speed.

[SIZE=11pt]Summarizing[/SIZE]

[SIZE=11pt]For my future 150 HP Yamaha (on my future 2014 2375 GCW), [/SIZE]

[SIZE=11pt]these are the estimates of my fuel costs:[/SIZE]

[SIZE=11pt]at about 11 MPH (2500 RPM) it will cost me about $1.25/mile;  ($13.50/hour)[/SIZE]

[SIZE=11pt]at about 19 MPH (3500 RPM) it will cost me about $1.30/mile;  ($26/hour)[/SIZE]

[SIZE=11pt]at about 30 MPH (4800 RPM), it will cost me about $1.67/mile;  ($50/hour)[/SIZE]

[SIZE=11pt]at about 37 MPH (5800 RPM), it will cost me about $1.75/mile.  ($78/hour)[/SIZE]

Please consider providing your best estimate of what you think it costs you to run your boat’s engine at WOT, at 3500 RPM (cruising speed) and at 2500 RPM (a slow comfortable speed) by using what you know about your own boat speed and simultaneous engine RPMs.  If you don’t know your engine’s GPH fuel efficiency, you may be able to estimate this from the Yamaha Performance Bulletin. If a lot of owners enter their data, I think we will see some very interesting (and very expensive) results.  

By the way:  

($5 per gallon) times the (# of Gallons per hour) = (your fuel cost in Dollars per hour)

If you wish to participate and submit your results, you can use the following template to record your results if you want:

I have a  ________  year Bennington  ______________  model with a ________ HP engine.   

At WOT I go about _________ MPH at _________ RPM.   According to the Yamaha Performance Bulletin (Y.P.B.) I will probably use up about  _______  GPH at WOT.  Multiplying this same  _______  GPH  times $5 per gallon means it will cost me about  $__________ dollars per hour to run my boat at full speed for a whole hour; and this same $_________ dollars per hour DIVIDED BY ___________ MPH means it will cost me about  $___________  dollars per mile for every mile I run my boat at full speed.

At 3500 RPM I probably run about  ________  MPH and according to the YPB I probably use up about  _________  GPH.  Multiplying this same  _______  GPH times $5 per gallon means it will cost me about  $_________  dollars per hour to run my boat at cruising speed for a whole hour; and this same $_________ dollars per hour DIVIDED BY ___________ MPH  means it will cost me about  $___________  dollars per mile to run my boat continuously at cruising speed.

At 2500 RPM I probably run about  __________  MPH and according to the YPB I probably use up about  _________  GPH.  Multiplying this same _______  GPH times $5 per gallon means it will cost me about  $__________  dollars per hour to run my boat as a slow comfortable speed for a whole hour; and this same $_________ dollars per hour DIVIDED BY ___________ MPH means it will cost me about $___________  dollars per mile to run my boat continuously at a slow, comfortable speed.

DAVID
 
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ct0218

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Wow David, a lot of calculating there! Based on your numbers, my operating costs will be just slightly higher than yours since my 2550 will be almost 2 ft longer and 300+ lbs heavier. I know that wind can greatly affect speed, mileage and performance numbers, and that helps me some on my primary lake. We don't seem to get a lot of wind on Fontana, maybe because of the mountains all around the lake that tend to block it. Anyway, if mine performs at, say 90-95% of what you computed, I'll be happy.
 

Bamaman

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Eagle:  Your numbers are very interesting, however there is a little that's missed running in the real world.  I'm with you that I seldom run at full throttle for very long on my 24SSLX with a F150 motor.

And if you get below 3000 rpm's, and you're going to easily fall off a plane.  I'm your age, but we're just not ready to settle into boring slow rides for very long.

I usually cruise @ 3000-3500 rpm's at a comfortable pace getting about 4.5 mpg.  (I think in terms of mpg rather than gph.)  We made a 125 mile run the length of Pickwick and back in August, and it was a great day.

With gasoline costing $1.00 per gallon more on the water, I'm not beyond hauling $3.05 gasoline in Jerry Cans to save money.  Saving money always makes me feel good--or allows me to run that much farther.
 
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BigKahuna

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When it comes to going to the lake on a gorgeous day to spend time w/my family/friends and cruise or hang out at our favorite coves/sandbars around the lake............... Or if the kids (grown up kids) want to ski, wakeboard or tube......................if the boat needs gas......................Fill it up!!!!!!!!!! Never really thought about what it costs to run it, just run it!!!!!!!!!!!!!!!!! Ha! 
 

SEMPERFI8387

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This topic is the ONLY reason I'm happy with our 20HP restricted lake. If I run full throttle ALL DAY LONG , I barely put a dent in our tank. Ok, maybe 5-6 gallons. On a heavy use weekend I'm lucky to burn 5 gallons. I don't think I burned 25 gallons this year, we just sat on the cove more often.

I have to laugh when I look at the GPH on our motor on the Yammi Perf. Bulletins.

Gas can get to $20 gallon, I don't care, as long as I have enough to get to a cove or the island, I'm happy ......
 

Eagle 1

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SemperFi,

I just found you at Lake Marburg on the Map.  I also looked at some pictures of your lake on Google Images.  Very Pretty.  1275 acres.  26 miles of shoreline.  Nice.  When I was about 6 years old, my father took me to Green Lake in Wisconsin, which as you may know, is a small lake of similar size, having about 1320 acres.  It was the first time I'd ever been boating on a lake and I loved it.  The size of the lake helps to answer my question about the 20 HP restriction.  I presume you occasionally beach your pontoon boat at the west end of Long Island and enjoy one of the two coves immediately south of the Route 216 Bridge (as opposed to the larger area of the lake somewhat southwest of Route 216).  Am I correct, or am I way off?  And, given the 20 HP restriction, how fast can your boat go?  

My previous boat was a SeaRay 210 with a 210 HP stern drive and during the years I owned it (1996 though 2006) I didn't  care at all what I spent on fuel.  My opinions about fuel were identical to those expressed by Daril (above).  In fact, what Daril said sounds exactly like what I have said to myself and to many others, many times.   I will always believe that the pleasure of boating can be so great that the fuel costs really don't matter.  Back then, I always had the money, and the prices didn't matter.

That being said, I'll be retiring in 4 years at age 66 and so most of my future boating will be done while my wife and I are on a fixed income.  Since I won't have as much spending money in the future, when I was first wondering what size engine I should buy for our future boating on a fixed income, I blogged on the Internet and asked for opinions.  One of the bloggers was 70 years old and he said he thought that after several years of paying fuel expenses for my 150 HP engine, that I would wish I had purchased the 115 HP instead of the 150 HP and that eventually I might wish I had even purchased a 90 HP.   That kind of blog answer made a lot of sense coming from someone who evidently had a lifetime love of boating as great as my love for boating was, so I had to take his answer seriously.  My guess is that if you took a survey of boaters in their prime earning years and compared them to boaters on a fixed income, that their perspectives about fuel costs might be somewhat different.   

David 

Daril,

More power to you.  I hope you never reach a place in life where you feel the need to restrict your boating pleasure just because of your wallet.  Currently I am in the same situation as you are and I don't care about the fuel expense at all.  But I am at a transition point in my life, and within 5 to 10 years, I expect fuel costs will mean a lot more to me then than they do now.

David 
 
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Rockie69

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Maybe Bennington will come out with a solar powered pontoon in 5 to 10 years. How awesome would that be. A full day on the lake at wide open throttle, pulling the kids! AND NOT HAVING TO STOP TO FUEL UP!
 

Eagle 1

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Jared,

And just think of how QUIET a solar powered engine might be.  Full speed, with nearly complete engine silence, hearing only the water splashing against our boat and the wind in our ears.  Sounds like heaven (literally).  

David
 

highpond

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Hi All;

I've been all around boats my whole life. I owned my first at 17. I've had sail boats, the last 30', I've had power, the last 34' :wub:  with a pair of 454 Mercs. If gas was a concern  it was with the 34'. A weekend was 200 gal. and gas was then in the high $2.00 per gal. When we filled we ordered by the gallon and not but how much. All that boating was done out of Onset, MA. Cape Cod Bay and Nantucket Sound. Now I'm retired, :D   moved to SC and own a Benny. with a 50 Merc. I still order gas by the gallon. 4 & 5 at a time for the jerry jugs. Spend the day on the lake and arrive home knowing the wallet is still intact. (you do have to watch pleasure spending) How things have changed. By the way with 2 of us on board the merc. can get up to 5k RPM and give me 19MPH. But most of our running is in the 20 to 2500 range.

Life is beautiful :)
 

Eagle 1

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Highpond,

I agree entirely.  I've owned a sailboat and 4 powerboats (2 outboards ad 2 stern drives).  I'm only 62 years old and at this point I still don't have to watch my fuel budget, but I'm only on the water maybe 10 to 25 days each year max.  I look forward to my golden years of retirement on Lake Norman even though I will have to watch my pleasure spending carefully, because once I'm retired at Lake Norman, I can be on the lake every day for 6 months straight (180 days) and if I were to boat 180 days a year, then the fuel bills would destroy my finances.  My guess is that the temptation is great to boat more frequently when you are retired, but that this temptation is balanced by the frequently fixed income.

David
 
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highpond

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David

Fixed income is sometimes a problem The Months with 5 weeks between checks can kill you. We live nearby Lake Bowen in northern SC so we trailer down a couple of times a week. It's a mediam size lake so it doesn't take much to go from end to end. We anchor in one area that is quiet during the week but forget weekends TOO busy! We like to go out to Lake Keowe but now your talking 15 gallons of gas, (130 miles round trip over route 11) for the SUV (yup that's 9 MPG) plus maybe another 10-12 for the boat. @$3.10 a galion $75 to $80.00. But we love it. so you make do.
 

Bamaman

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I recently saw a video of the dashboard (speedometer and tachometer) with a 115 hp on the same boat I have.  I could tell that there's a significant difference in performance between the two.  My F150 is a good motor for compromise on any boat capable of handling that much power. 

I had my 24SSLX running 42 mph GPS three weeks ago @ 6200 rpms.  40 mph is about the point of no return on a tritoon, and 30 mph is the point of no return on a twin toon boat.  Above those speeds, and it takes much more horsepower to get them substantially faster.

I'm fortunate that we just back out of our boathouse, and we're out and running on big water.  If gas prices get too high for this young retire, I can go 1/2 mile into the middle of the river channel and just float for hours.  Every once in awhile, I may have to start it up and move 1/2 mile upwind.  It's easy to get by on a gallon for the afternoon if need be.  With a pontoon/tritoon, you can make anything out of your day on the lake, including making your boat the center of "Party Central."
 

Eagle 1

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I agree, Bamaman, that a Yamaha F150 is a great compromise for power and economy, which is why my future 2375GCW will come with an F150.  I'm guessing that my boat will be about 500 lbs. or more heavier than yours and I don't expect to reach 42 MPH, but probably just 37 MPH.  The Yamaha Performance Bulletin also confirms that once you've reached 40 MPH, it seems to take a lot more horsepower to make your boat go significantly faster.  And as far as your third point goes, party on!

David
 

ct0218

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I went with a150 for exactly the same reason. My Tracker bass boat that runs 46 mph WOT with a 90 Merc, but I run at 4000 rpm and 30 mph 95% of the time. I guess I have more time than money, and usually I'm in no big hurry. Beautiful scenery, and an occasional deer, bear, bobcat or turkey to watch on the shore. I boat during the week, not on weekends, and running slower gives me better mpg to go more often. I considered the 200hp I-4 Yamaha, but with a 6 yr warranty on the 150, and 3 year on the 200--and $4000 difference in cost, it was a no brainer for me.
 

lakeliving

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I went with the 200 i4 and negotiated in an extra warranty. Not going to be hitting full throttle every time out but when I want it, it's there!!
 

kaydano

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"One of the bloggers was 70 years old and he said he thought that after several years of paying fuel expenses for my 150 HP engine, that I would wish I had purchased the 115 HP instead of the 150 HP and that eventually I might wish I had even purchased a 90 HP."

I looked back on my own personal records, and that statement posted above is dead wrong.

I had a 115HP and traded it for a 150HP.  The 150HP uses LESS gas than the 115HP did.  LESS.  To go the same MPH, the 115HP has to work a lot harder than the 150HP...

Here's the data for my two motors running on the same boat with a light load.  Note that both my motors were Mercury four strokes, but I would guess the Yamaha's are similar.  The 115HP numbers were with my Spitfire prop.  It dropped my max speed down to around 32 MPH from 35 MPH with the black max.  Max speed with my 150HP is ~42 MPH.

MPH.....115HP RPM.....150HP RPM.....115HP GPH....150HP GPH

7.5......2500...........1700.........1.7 Gal......1.8 Gal

12.......3500...........2250.........2.9 Gal......2.4 Gal

20.......4500...........3000.........5.0 Gal......3.6 Gal

24.......5000...........3600.........6.9 Gal......5.3 Gal

30.......6000...........4250.........9.9 Gal......7.5 Gal

As you can see, at any given speed the 150HP uses less gas.  That said, the max fuel burn rate on the 115HP is about 10 Gallons per Hour while the 150HP can burn 14 Gallons per Hour at WOT.  If you have the discipline to not run full throttle all the time, the larger motor is easier on gas.  I would be curious to see numbers like this on the 200 and up...

Your post made me go look back on the last 50 hours of motor time on my old 115HP, and my average burn rate was 3.3 Gallons per hour.  This includes running at idle speed in the marina, the occasional WOT, pulling tubes, slow cruising, etc.  Everything is rolled in together.  The last 50 hours of motor time on my bigger 150HP had an average burn rate of just 3.7 Gallons per hour.  The slight increase is because I use that extra horsepower when pulling tubes, and the numbers reflect this.  But THAT is the reason (tubing performance) why I traded up on the motor in the first place.  Apples to apples, or MPH to MPH, the 150HP uses less gas because it doesn't breath as hard.  But I do make use of the extra HP pulling tubes.  The 115HP was at WOT almost 100% of the time when pulling a tube, and it just wasn't enough.  The 150HP runs at around 4500 RPMs pulling a tube (if memory serves), but because I pull them faster with the 150HP than was possible with the 115HP, I assume that is why my gas consumption increased, but note the increase is barely noticeable!  I am very happy with the decision to trade up to the 150HP, and the gas consumption just ends up being icing on the cake.  Going into the trade, I figured the 150HP would use a LOT more gas, but it's just not true.  A pleasant surprise. 

So, the next time someone says a bigger motor just burns more gas, take it with a grain of salt.  It WILL burn more gas at WOT, but then again, you will go a lot faster.  But who goes WOT all the time?  If you just plan on cruising at a certain MPH most of the time, the 150HP will use less gas than the 115HP.  Andy's comment above on the extra HP hits the nail right on the head:  "when I want it, it's there!!"

By the way, I see I spent over $900 on gas last summer...  Semper, I thought you'd like hearing that one.
 
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lakeliving

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Good data there Dan. I'll be curious to see how the 200 does vs the 115. We're almost in the same boat with wanting more performance...on second thought we are in the same boat 24ssl!!!
 

kaydano

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I am VERY curious to hear your performance numbers with that 200HP!

But, that could end up showing me my PADS was just in remission.  It will be VERY costly for me if PADS comes back with a vengeance, as my 24SLL with Express tube is max out at 150HP. 

I'd have to get a whole new boat...
 
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kaydano

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Hey Link - Let me know if my fuel burn info comes in hand convincing your wife to get a 150...
 

Eagle 1

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Way to go, Kaydano.  It is always best to get data from the same boat using the same propeller!   Excellent presentation.

I guess the 70 year old boater I quoted may have been wrong.

David
 
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