Fuel efficiency

[552Evo]

So I had a morning on the water chasing dinner today and for the first time ever I had a look at the "fuel" options on the Vessel View system.
My boats got a Merc 150 4 stroke.
So from memory,
WOT @ 5800rpm was about 38knts using 56 litres/hour.
@ 26knts using 26 litres/hour
For me in the conditions today, 26knts was a comfortable speed getting from A to B, as I moved around a bit today.

I want to understand and not guess the fuel efficiency side of those figures. Sorry if it is obvious to to some but this time today my head is mush after working till midnight last night then up at 3am to catch the tide at 5:30 and I'm still going at 9 pm. Boat home and cleaned up in time for the Boss to get home at 5pm then a leisurely 2 hour drive to "get away" for the night.
So at 26 knots per hour, using 26 litres per hour, does that equate to 1 litre of fuel to 1 nautical mile ?
If it does or doesn't, is that good bad or average ?

Thanks.


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[Cape Crusader]

Correct, but it's not knots per hour, it's just knots. I'd say thats about par for the setup
Cheers
Rod

[Marchy001]

I’d be happy with those figures. For my 5.9 vermont with a DF140 I was 1nm/L as you are. With a F225 it was .7-.8nm/L and now with a 175 Etec I’m usually around .8-.9nm/L.

[552Evo]

Thanks Rod and Marchy,


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[Force3]

At cruise (2017 yellowfin 6700 hard top) with 225HO G2 - 3250rpm, 43 kph (23.2 kn) I get 2.0 km/l or 1.1 nm/l. 4 POB and full fuel in calm conditions.

[Dignity]

EVO, you should do a run and test the boat at various revs, 500, 1000, 1500, 2000, 2500, etc until WOT, have someone write them down and you could be surprised at the results. Now if you decided to test a new prop do it all again and compare again. I usually graph the data and you will find that neither fuel consumption nor revs rise consistently. Also if you are doing it on calm water you will get different results if you are running with the wind or against, against usually gets better results as the boat acts like an aerofoil.

[ranmar850]

Does your VV give you the option of showing litres/NM or KM? These are your most meaningful figures. Litres/hr are only relevant to how many miles/KM ( I am of the personal opinion that kilometres do not exist the wet side of the high tide mark, but thats just me) you are doing in that hour. So stick with a km or nm per litre readout. This is how you find your sweet spot, and you'll also know how much more it is really costing you when you decide to go hammer down on flat water.
And with your merc, you also have the option of the Vessel View mobile. Before someone starts eyerolling and saying WTF do you want it on your phone for, it gives you a hard record of what you are actually doing, and can also see faulty codes. It's a bluetooth module which plugs into your system, I have one to go with my new 150, soon to be fitted. Hard numbers for the sea trial, if nothing else. See it here. https://www.mercurymarine.com/en/au/gauges-and-controls/gauges-displays/vesselview-mobile/

[552Evo]

Thanks Dignity yes I should do that recording of data. Will do.
Ranmar when I checked on Saturday the display said litres per hour. I'm not 100% sure I can change that setting, maybe there's another screen.
I like the idea of the mobile app.
So then I'll need a Bluetooth module for the Vessel View and another module for the Simrad, where does it end ha ha. By the time I get the modules there will be something else newer and better.
I've never paid too much attention to the VV to be honest. Half of the data fields are empty because they need additional sensors. I'll usually only pay attention in what it's got to show if there's something wrong.
What would be good is if you link it to the Simrad and it shows you litres per trip with distance covered or something like that.
Just on a side note though I think my next investment would/should be a decent transducer before I spend $$$ on extra Bluetooth modules.


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[scottar]

Shouldn't need the Fuel Data Memory module to get a fuel economy (distance/litre) readout if the NMEA2000 is hooked up. You will need it if you want to set up a virtual tank to show litres remaining.

[552Evo]

Thanks scottar, this module and nmea stuff is an unknown for me.
I can understand the need for a module to facilitate Bluetooth, but what does the nmea do ?
I thought it was like a network hub is that right ?
So I need a "fuel data memory module" to get all the fuel data ? This is getting crazy.
I've tried before to set up the fuel remaining on VV and it seems to me you've got to set it up every time you fill it and most of the time I would only use 23-30 litres so I don't bother. But if I had a virtual tank via an nmea then this would be easier ?



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[banksmister]

116774

Is that what you want it to do/ look like

116775

[552Evo]

Sorry banksmister, I can't see the image ?
Can anyone else ?


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[PixieAU]

Sorry banksmister, I can't see the image ?
Can anyone else ?


Sent from my iPad using TapatalkI can see the second image, not the first

[552Evo]

I can see it now.
That's the same screen I've got but I don't think I have the trim and fueltrip. I've got the trim as a bar graph on the main page only when I activate the trim. I'd like to have as many data fields functioning as possible - so is it just a matter of setting up something to get all the fuel and trim fields or are there sensors that need installing ?


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[scottar]

Thanks scottar, this module and nmea stuff is an unknown for me.
I can understand the need for a module to facilitate Bluetooth, but what does the nmea do ?
I thought it was like a network hub is that right ?
So I need a "fuel data memory module" to get all the fuel data ? This is getting crazy.
I've tried before to set up the fuel remaining on VV and it seems to me you've got to set it up every time you fill it and most of the time I would only use 23-30 litres so I don't bother. But if I had a virtual tank via an nmea then this would be easier ?



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If you want to use fuel data in the Simrad, NMEA2000 is the communication protocol (essentially it is canbus) that it uses to communicate with the engine. Not sure whether Merc provides this as standard with their smart gauge set ups or whether you require an interface.

Once it is all connected, the engine will send fuel flow data to the Simrad which it can display as flow/time or by using it's GPS it can calculate economy (flow/distance). What the Navico unit's don't have is the ability to set up a virtual tank all by themselves. They require a fuel data memory module. Essentially the module is the virtual tank - you tell it (by programming it with the Simrad display) how big your tank is, fill the tank up, tell it the tank is full and then the module deducts any flow indicated by the engine and calculates how many litres are left and sends this data to the Simrad. The set up does require that you either tell it when you add fuel by either adding however many litres you add or by telling it you have filled the tank.

[552Evo]

Thanks scottar that information and explanation is gold, I'll try to contact Merc or my local dealer and ask if I need a interface for the nmea and the Simrad. And I'll investigate the fuel data memory module for the Simrad for the virtual tank.
I'd better start saving me thinks.
Thanks again it's all that much clearer now.


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[Jason Green]

Hi all
In my opinion actual nm travelled are completely different from a fishing trip then what the gauges will tell you because when you are planning a trip you don’t factor in the extra travel due to swell etc to get there
I always get completely different readings on how far I travel from the SafeTrx app then the Yamaha gauges tell me so my fuel economy really does not match my planned trip
But I always have plenty up my sleeve so I don’t have to annoy some poor volunteer in the middle of the night to come rescue me lol
My gauges tell me I have used more than I have been like that from the start and I like it that way
That’s my 2 bobs worth




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[Dignity]

Hi all
In my opinion actual nm travelled are completely different from a fishing trip then what the gauges will tell you because when you are planning a trip you don’t factor in the extra travel due to swell etc to get there
I always get completely different readings on how far I travel from the SafeTrx app then the Yamaha gauges tell me so my fuel economy really does not match my planned trip
But I always have plenty up my sleeve so I don’t have to annoy some poor volunteer in the middle of the night to come rescue me lol
My gauges tell me I have used more than I have been like that from the start and I like it that way
That’s my 2 bobs worth




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With the gauges I've struggled to work out exactly how far I've travelled, can't use the GPS as it includes drifts, even all that swaying backwards and forwards at anchor of a night. How does the Yammy gauge calculate distance, is it some pressure device through that tiny little hole in the leading edge of the gear case. I guess I prefer to have more fuel left over but I will still go with best estimate, one trip I did I supposedly used 345 litres leaving 15 litres in the tank but when I completely drained the tank 55 litres came out. Now if I'd known that I would have opened the throttle on the last 60km across Hervey Bay which would have made Mojoes happier as he slowed down to accomodation me. I know fuel usage is a little different to distance travelled but on my calculations before and during the trip the gauges were telling me what I'd worked out. Like you Jason, I prefer to have more than what the gauges are telling me. You been out lately?
Sam

[scottar]

The yamaha gauge can take speed from either water pressure or gps depending on set up. It also automatically deducts 10% as a reserve I think.

[Dignity]

The yamaha gauge can take speed from either water pressure or gps depending on set up. It also automatically deducts 10% as a reserve I think.

Scott, my gauges are from water pressure then as I don't have it connected to the GPS, yes the gauge is setup so that you tell it the tank size and it only shows 90% ie in my case a 200 litre tank shows 180 litres.

[swof63]

If you have a recent simrad unit, it should be able to run the full current VesselView software. You then need the vesselview link to bridge the smart craft data to nmea for the simrad. I know my vesselview 702 is a cutdown simrad Nss 7 evo2 ( has Gps but no sounder ) I think the new 703 is a full simrad unit. In the vesselview link doco it says you can run the full mercury vesselview software on various lowrance and simrad displays.
The fuel management on the 702 seems pretty accurate and displays flow rates and economy and trip fuel. I know my Garmin seems to get engine data from the link as well and also displays fuel data.


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[Moonlighter]

Hi all
In my opinion actual nm travelled are completely different from a fishing trip then what the gauges will tell you because when you are planning a trip you don’t factor in the extra travel due to swell etc to get there
I always get completely different readings on how far I travel from the SafeTrx app then the Yamaha gauges tell me so my fuel economy really does not match my planned trip
But I always have plenty up my sleeve so I don’t have to annoy some poor volunteer in the middle of the night to come rescue me lol
My gauges tell me I have used more than I have been like that from the start and I like it that way
That’s my 2 bobs worth
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I have my Suzuki DF115 networked to my Lowrance and Simrad displays.

After the initial connection some years ago, I had to calibrate the fuel flow and now, fuel used data is incredibly accurate. Within 1-2%.

The Simrads now have Merc and Suzuki engine data integration. Google will provide further info. Basically you get a dashboard customised to the data output by your brand motor.

http://ww2.simrad-yachting.com/en-GB/Products/Engine-Management-and-Networking/Mercury-VesselView-Link-en-gb.aspx


Also, my Simrad GO7xse has a neat feature called Trip Intel.

https://m.youtube.com/watch?v=U83TJEuLbvk

Each time shortly after I launch, I get a message pop up asking me if I want to start a new trip or continue the last trip.

Each trip is then individually logged on a record, and I can call it up and see for each trip, the date, distance travelled, trip time in hrs and minutes, avrage speed, and fuel used. There are also overall stats that give me average fuel economy. Very neat stuff, and very accurate.

[shakey55]

I’ve a 2000 model Johnson 115 (2 stroke). I wish I could have a gauge that showed my fuel usage.

I’ll just have to wait until I upgrade one day.


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[scottar]

Scott, my gauges are from water pressure then as I don't have it connected to the GPS, yes the gauge is setup so that you tell it the tank size and it only shows 90% ie in my case a 200 litre tank shows 180 litres.

There are a few different series of the Yamaha gauges Sam. Some use an in line fuel flow sender and some use the Yamaha canbus data. If you have Command Link series gauges, connecting to a NMEA2000 plotter or network is quite often a quick and easy exercise - just a cable in a lot of cases. If it pre dates Command Link it can't be done and if it is the latest Command Link Plus the literature advises an interface is required - although it advises one is required for Command Link which I know to not be the case - I haven't come across any Command Link Plus to dig any further into it.

[Dignity]

Scott, I wish I could understand your last post but when it comes to all of this stuff I am totally lost. For interest sake I will try and find out what my gauges are and take it from there. I don't think there is an inline sensor unless it's in the motor.

[scottar]

I’ve a 2000 model Johnson 115 (2 stroke). I wish I could have a gauge that showed my fuel usage.

I’ll just have to wait until I upgrade one day.


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You can but it needs to run on an impeller type sender - some of which are accurate and reliable, some not so much. Unfortunately the reliability and accuracy seems to be determined by luck of the draw - not a particular brand or model. The cost is also up there a bit if you need a full gauge/sender/memory module if required/NMEA2000 backbone set up. If it is just the sender and backbone kit to work with an existing NMEA2000 device - namely a Garmin as these have the fuel management software built in (no extra memory module required) it's not so bad.

[scottar]

Scott, I wish I could understand your last post but when it comes to all of this stuff I am totally lost. For interest sake I will try and find out what my gauges are and take it from there. I don't think there is an inline sensor unless it's in the motor.

Post up a pic of the gauges from the front and the rear and I'll see what I can nut out.

[robcam]

[QUOTE=552Evo;1640315]Thanks scottar that information and explanation is gold, I'll try to contact Merc or my local dealer and ask if I need a interface for the nmea and the Simrad. And I'll investigate the fuel data memory module for the Simrad for the virtual tank.
I'd better start saving me thinks.
Thanks again it's all that much clearer now.

Evo, not sure if you have this sorted yet but my 2c for what it`s worth. I have the same motor as you connected to lowrance units. The vessel view gauges act as the interface and have an nmea port on the back that you just need to connect to your backbone. Look up nmea starter kit on lowrance site if you don`t have backbone yet. I have the data set up as overlay on the chart as attached.

[552Evo]

Thanks robcam, no nothing sorted yet. After reading all the information in this thread I’ve established I’d better do 2 things.
1-save up.
2- despite all the information I’ve read, I’d better go see and talk to a knowledgeable retailer that can help.
It seems depending on where you look on the www there are different ways to do this stuff too.
I’m not going to be networking a bunch of stuff I’m mainly keen to sort out fuel usage one way or another. Really it’s a catch 22 because It seems to me from what I’ve read a fuel talk level sensor is not so accurate and I gather “fuel used” using one of the vessel view network options may be the way to go but it’s not straight forward either way.
At the end of the he day anyone in control of a boat wants to retain a fuel buffer (eg 30% capacity) and not run the tank down to 5 litres left.
So a simple level sensor may be the simplest gauge of that.


Saltwater fishing, boat mad but has a job that gets in the way.

[shakey55]

You can but it needs to run on an impeller type sender - some of which are accurate and reliable, some not so much. Unfortunately the reliability and accuracy seems to be determined by luck of the draw - not a particular brand or model. The cost is also up there a bit if you need a full gauge/sender/memory module if required/NMEA2000 backbone set up. If it is just the sender and backbone kit to work with an existing NMEA2000 device - namely a Garmin as these have the fuel management software built in (no extra memory module required) it's not so bad.

I was of the belief my motor is to old to run on NMEA

I’ll just stick with the normal fuel gauge and try and get a rough idea from fuel used to distance travelled

Thanks


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[Chimo]

Part 1
With older gear without backbone setup the triducer on my Furuno (old) gives a reasonable indication of distance traveled given that you allow for tides and current (already some errors) and when you add in the question mark about how full the tank was (based on the angle of the boat hull when you poured fuel in) and then add in the hours run (off your watch or the hour meter s;with two motors) you can guesstimate the fuel you used.

Part 2
To be sure, to be sure (Irish consideration) when you return to home port, you then add a known quantity of ULP91 through a filter funnel (to catch water and other gunk) and see how close your guesstimate was in part one above was.

The above methodology takes into consideration the questionable readings given by the fuel sender and gauge, how high or low the bow was when you last filled the tank and the myriad other factors like wind and tide and current and the speeds you ran at during the "cruise"

My fuel usage / economy is a range rather than a precise number and if in doubt I just carry a few extra drums.

Lifes too short to stuff a mushroom so as they say in Qld "Don't you worry about that!"

PS the other method is ti use a dip stick but too hard on the Vag.

[Smithy]

Sam,

on my older Lowrance plotter I can set a threshold speed for my distance log. Make it 3knots or something then all of your drifting won't count in the distance log of your plotter.

[scottar]

I was of the belief my motor is to old to run on NMEA

I’ll just stick with the normal fuel gauge and try and get a rough idea from fuel used to distance travelled

Thanks


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Yes - your motor is too old but you can run an in line fuel flow sender like these

https://buy.garmin.com/en-AU/AU/p/11561

Navico also make one if you use lowrance or Simrad. You also need a compatible NMEA2000 display if you don't already have one and a backbone starter kit. If you need to buy all of it it gets pricey but I guess it depends on just how badly you want the info

[shakey55]

Yes - your motor is too old but you can run an in line fuel flow sender like these

https://buy.garmin.com/en-AU/AU/p/11561

Navico also make one if you use lowrance or Simrad. You also need a compatible NMEA2000 display if you don't already have one and a backbone starter kit. If you need to buy all of it it gets pricey but I guess it depends on just how badly you want the info

I have a Garmin 75

For all the bother and money, I think I’ll just do some rough sums and work it out.

Thanks for the info my friend


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